Best CBD Oil for High Blood Pressure (Hypertension)

Knowing that CBD oil can help with blood pressure is a good start,but you also need to find the ideal product for your needs. In the search for the best CBD oil, pay attention to the following factors.

Certificates of Analysis from an Independent Lab

As mentioned earlier, most reputable CBD retailers offer certificates of analysis or similar documentation. You should always choose a company that has this information available and focus on those that offer independent testing from third-party companies. In-house testing is better than nothing but could come with an inherent bias. If a company has no testing on its products, then stay away. The products may be perfectly safe, but it may also have something to hide.


The dosage of the CBD should also play a role in your decision. If you are starting to take CBD oil for blood pressure, you should try a method like a tincture or drops which allows you to adjust the dose easily and deliver the exact dosage. Tinctures and liquids tend to make it easiest to adjust doses. If you were to use gummies or capsules, you would only be able to double or triple the dose, not increase it by fractions. If you prefer those methods, you could also try taking a capsule or gummy, then supplementing it with a bit of tincture.


You should consider the ingredients in your cannabidiol oil, as well. Many products will only have CBD extract and carrier oil. If you opt for capsules, gummies, or flavored options, there will be more ingredients. Ensure that there are no harmful ingredients. You should also opt for CBD from hemp grown without chemicals, as the residues may remain in the CBD extract.

THC Content

You also need to decide whether you want a CBD oil that contains THC. This depends on your local laws, whether you need to pass drug tests, or if you drive or operate heavy machinery, or what your preferences are.

Some Top CBD Oils for Blood Pressure

To get you started in your search, here are some of the top CBD oils for blood pressure on the market:

CBD Gel Capsules Product

Medterra CBD Gel Capsules: For those who prefer their CBD in capsules, this is a good option. You have a choice of 25 or 50 milligrams per capsule. The same company also offers tinctures and more.


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240mg Full Spectrum CBD Oil, High Grade Hemp Extract (50mg/ml) Product

NuLeaf Naturals 240-milligram Cannabidiol .17 fluid ounces: This is one of several concentrations from NuLeaf Naturals. As the lowest concentration, it is the company’s best option for those new to CBD oil. The product is lab-tested and fully organic. It is full-spectrum, so it contains THC in small quantities.


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750mg Lab Grade CBD Oil Product

Spruce 750-milligram Lab Grade CBD Oil: A full dropper of this CBD oil delivers 25 milligrams of full-spectrum CBD. The company also offers a higher-potency version.


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The Takeaway

CBD oil is a natural method of reducing your blood pressure, helping patients control hypertension. It is available in multiple forms and is non-psychoactive. You can supplement it with other lifestyle changes to avoid the harmful effects of pharmaceutical drugs. If you take CBD oil for blood pressure, be sure to monitor your blood pressure regularly to ensure you effectively manage your levels.

CBD oil has made headlines in recent years by offering a natural alternative to medications for a wide range of treatments. People use CBD for a range of benefits, from relieving pain to reducing the risk of seizures. Keep in mind that using CBD oil for blood pressure only helps those with high blood pressure. It would likely worsen the situation for those with lower blood pressure.

What to Know About CBD Oil

CBD oil contains CBD, cannabidiol, as its primary active ingredient. Cannabidiol is associated with the previously mentioned benefits, including controlling blood pressure.

Comparing CBD and THC

CBD comes from cannabis, and is naturally found in hemp plants. CBD is one of more than 100 cannabinoids that occur naturally within the plant. This compound is also commonly used to produce CBD hemp oil supplements. Hemp seed oil is produced by extracting the oil from the seeds of the hemp plant itself. This oil is abundant in nutrients, such as omega-3 and omega-6 fatty acids, making it ideal for digestion. Although some people refer to “hemp extract” as hemp oil, the term “hemp oil” is synonymous with the term “hemp seed oil.”

Chemical compounds in cannabis, called cannabinoids, have shown various potential benefits by activating the body’s endocannabinoid system. The medicinal efficacy of cannabis can be optimized by incorporating the various cannabinoids, flavonoids, and terpenes that are intrinsic components of cannabis plants.

CBD is non-psychoactive, contrasting with THC (tetrahydrocannabinol), another major cannabinoid. THC is the largest factor contributing to the high associated with using cannabis. By contrast, consuming CBD without any THC does not produce those effects.

This means that nearly everyone should be able to function as they normally do when taking CBD. The lack of high lets you continue with work, school, and other commitments without a decrease in performance. It also makes CBD oil safe to take, even for those who must pass regular or random drug tests.

Including or Excluding THC

Just keep in mind that for CBD oil to be non-psychoactive, it must not contain any THC. Products containing CBD isolates do not have THC, while full-spectrum CBD products will. Any product you buy should also state the percentage of THC, information which you can also get from its certificate of analysis.

Some people who use CBD oil as a natural remedy for blood pressure or other uses prefer small quantities of THC. This is due to the entourage effect, which means that THC and CBD working together produce stronger benefits than just CBD alone.

What to Know About Blood Pressure Problems

When it comes to blood pressure issues, CBD treats hypertension, which is elevated blood pressure.

Typical Onset

Most people have high blood pressure at some point in their lives. It is particularly common to occur over time, affecting people as they get older.

What Causes It

Multiple factors work together to create a risk of high blood pressure. Eating too much fat or salt can play an important role. Family genetics are also a significant risk factor.

With high blood pressure, the walls of your arteries accumulate plaque, causing them to narrow. This can also cause weakening of crucial blood vessels. Those vessels can then clot, rupture, or leak, leading to heart attacks and other serious consequences.

Risks of High Blood Pressure

Having high blood pressure comes with an increased risk of multiple issues, like strokes, blood clots, heart attacks, and Alzheimer’s disease. High blood pressure can also increase the risk of aneurysms, narrowed or weakened kidney blood vessels that stop the kidneys from proper functioning, vision loss from torn or narrowed blood vessels in the eyes, difficulty with memory, dementia, and metabolic syndrome.

The last of these is a group of disorders related to the metabolism, with symptoms like low “good” cholesterol, high triglycerides, increased waist circumference, high insulin levels, and high blood pressure. Metabolic syndrome increases the risk of stroke, diabetes, and heart disease.

Lifestyle Changes to Reduce Blood Pressure

In addition to using CBD to reduce blood pressure, you can make some other simple lifestyle changes to minimize hypertension. Start by adjusting your diet to be healthier. Try to reduce your intake of fat, salt, and cholesterol, as this reduces plaque build-up in the arteries.

You should also make sure to exercise regularly, as this strengthens your heart. Even a daily half-hour walk can have a positive impact. Also, work to manage stress, as stress can worsen your heart health and increase your blood pressure.

Traditional Blood Pressure Medications and Their Side Effects

While there are many hypertension medications available, they all come with side effects. By contrast, taking CBD oil for blood pressure has minimal side effects.

The common Angiotensin II receptor blockers (known as ARBs), such as Diovan, dilate blood vessels to fight high blood pressure. Their potential side effects include skin rashes, joint and back pain, flu-like symptoms, nausea, headaches, and diarrhea.

Metoprolol beta-blockers are also common, including Toprol-XL and Lopressor. These slow the heart rate to help with hypertension and the risk of a heart attack. However, they can cause diarrhea, constipation, vomiting, fatigue, anxiety, depression, insomnia, shortness of breath, and decreased libido.

Finally, angiotensin-converting enzyme inhibitors (ACE inhibitors), including Vasotec and Benazepril, prevent narrowing of blood vessels. Their potential side effects include skin rash, dry cough, headaches, dizziness, and diarrhea.

The common theme is that the medications control blood pressure but at the cost of bringing a range of other problems.

By contrast, CBD has very minimal side effects with nearly everyone tolerating it well. The World Health Organization indicates it has a good safety profile.

How Safe is CBD with ACEIs and CCBs for Hypertension During Pregnancy?

Motherisk research in 2011 found that the use of angiotensin-converting enzyme inhibitors (ACEIs) to treat hypertension during a woman’s first trimester of pregnancy may be associated with a higher risk of miscarriage.  

ACEIs and angiotensin II receptor blockers (ARBs) could cause fetal renal damage in pregnancy. Because of conflicting reports in the literature, their safety after first-trimester exposure has been debated. Motherisk’s study results also suggest that ACEIs or ARBs are not primary human teratogens, although they may be related to an increased risk of miscarriage. 

According to the results of a study, CBD responses were reduced in those taking statins, hypoglycemic medications, and beta-blockers, but not those taking ACEIs or nonsteroidal anti-inflammatory drugs (NSAIDs). Meanwhile, calcium channel blockers (CCBs) have not been known to heighten the risk of fetal abnormality. The information available concerning the safety of CCBs during lactation is limited, although they cannot possibly pose a risk to the nursing infant.

Cannabis may increase heart rate, so it is beneficial to use in conjunction with beta-blockers, which are formulated to slow down a hypertensive’s heart rate. Also, beta-blockers signal the blood vessels to expand and open, which improves blood flow and the flow of cannabis through the bloodstream. The increased blood flow allows medications to work more effectively.

In a 2015 study, the hemp seed protein hydrolysates (HPHs) were tested for in vitro inhibitions of renin and ACE, two of the enzymes that regulate human blood pressure. Researchers concluded that an optimized combination of the fast-acting and longer-lasting HPHs could provide daily effective systolic blood pressure (SBP) reductions. Still, women should avoid the excessive use of cannabis during pregnancy as it may cause the fetus’s cognitive impairment and increase the risk of miscarriage. One should consult a medical professional before including CBD in her prenatal regimen.

High Blood Pressure and The Immune System

A regular dosing of the hormone angiotensin II would give mice hypertension. However, mixing a molecule called 2-HOBA into the mice’s drinking water causes a significant drop in their blood pressure and returns it to almost normal. Vascular biologist David Harrison of the Vanderbilt University School of Medicine in Nashville led the group of researchers who did the study on hypertensive mice. The results of their observation could pave the way towards employing an innovative approach to hypertension treatment.

2-HOBA, a molecule derived from buckwheat, influences the immune cells. Another vascular biologist, Tomasz Guzik of the University of Glasgow in the United Kingdom, explains that the immune system plays an unexpected but critical role in hypertension. Scientists believe that immune cells collaborate with long-recognized miscreants like stress and dietary salt to increase blood pressure. Further tests on 2-HOBA in humans are already in progress. Harrison possesses a patent on its 2-HOBA for hypertension. He is optimistic that full clinical trials would lead to the discovery of new treatments that could control the immune system.

High Blood Pressure and PTSD

A study examined the link between high blood pressure and Post-Traumatic Stress Disorder (PTSD). PTSD is an anxiety disorder that can transpire after exposure to a frightening experience or trauma in which grave physical harm ensued. Distressing events that may trigger PTSD include violent physical or emotional aggression, natural or human-made calamities, accidents, or military combat. Other anxiety disorders that may coexist with PTSD are panic disorder (PD), social anxiety disorder (SAD), obsessive-compulsive disorder (OCD), and specific phobia.

Research shows CB1 cannabinoid receptors in the body help deactivate the recollection of traumatic memories so that one can choose to ignore them. Lack of endocannabinoids like anandamides can induce symptoms of PTSD, such as anxiety and fear. PTSD triggers intense stress that keeps a person in a state of consciousness and tension, making it very difficult to sleep. Cannabis can curtail or prevent the frequent occurrence of nightmares in those who have PTSD. Study shows that CBD may be an effective treatment for PTSD.


How CBD Helps with Blood Pressure

Some people want to understand how CBD helps with blood pressure instead of just accepting the fact that it does. When you consume CBD oil, it dilates or widens your blood vessels. Wider blood vessels allow for the blood to flow through more easily, even if there is plaque build-up on your arterial walls. The result is a reduction in overall blood pressure. By helping with blood pressure, CBD can also improve overall heart health and improve the heart rate.

The National Institute on Alcohol Abuse and Alcoholism completed a study showing that the endocannabinoids, including cannabinoids, suppress heart contractility in those with hypertension. This leaves room open for treatments that target the endocannabinoid system, like CBD and other cannabinoids. Other research indicates that anandamide, which our body’s natural equivalent of THC, can relax blood vessels.

Recent Studies on CBD for Blood Pressure

Humans have used cannabis for at least centuries, if not thousands of years, to treat a range of conditions. In recent years, scientists have conducted studies to demonstrate the effectiveness of CBD and other cannabinoids for treating blood pressure and other conditions.

University of Nottingham Study (2017)

In 2017, the University of Nottingham’s Division of Medical Sciences & Graduate Entry Medicine conducted a study to test how CBD impacts blood pressure. The study found that giving healthy volunteers just a single dose of 600 mg of CBD in a randomized manner reduced blood pressure. The study concluded that CBD lowers the resting blood pressure, as well as the potential increase of blood pressure due to stress. The study did indicate that further research is necessary to connect the CBD’s ability to treat cardiovascular disease firmly.

25-Study Review (2017)

This in-depth review examined 25 previous studies that looked at the interactions between CBD oil and blood flow dynamics, known as hemodynamics. The conclusion was that more research is necessary, but it seems that CBD can be used to treat a range of cardiovascular disorders. The review specifically mentioned using CBD to treat hypertension, stroke, and myocardial infarction.

CBD Can Lower Cortisol (1993)

A 1993 study from the University of San Paolo in Brazil in 1993 showed a positive interaction between CBD and cortisol. For those unfamiliar with it, cortisol is the “stress hormone” that your body releases when stressed. High levels of cortisol can increase your blood pressure, which is why stress causes high blood pressure. This 1993 study found that taking CBD lowered the cortisol levels of subjects.

By lowering cortisol, CBD oil can keep blood pressure within the desired range, based on this study. The study also indicates the potential of CBD for relieving stress via regulating your body’s cortisol excretion.

How Much CBD to Take for Blood Pressure

Start Small

Although recommendations for dosing vary, the consensus is that you should start with a small dose and work your way up. This minimizes the risk of side effects and saves you money thanks to the smaller doses. If you need to, increase the dosage slowly. You should find your ideal dose shortly.

Look at the Product Instructions

To get an idea of the proper CBD dosing, read the label and other information that comes with the product. Many have dosage suggestions, although this is not always the case.

Example Suggestions

One common suggestion for dosing of CBD is to take 25 mg twice every day. Others suggest between 10 and 20 mg one or two times per day. This would be the starting point, and you can increase your dosage if you need to.

There is also a common suggestion of calculating your dosage based on your weight. With this method, you would start with between 1 and 6 milligrams of CBD for every 10 pounds you weigh. Choose whether you go with 1 milligram, 6 milligrams, or somewhere in between based on the severity of your hypertension. Start with the lower end of the spectrum and work up to the higher end if necessary.

How to Take CBD for Blood Pressure

You can choose from multiple methods of taking CBD oil as this cannabidiol oil is available in various forms, depending on your preferences.

Drops and Tinctures

One of the most common options for taking CBD oil for blood pressure is via drops or tinctures. You typically place a drop or two under your tongue, offering simple oral administration. Many people like this method because of the convenience associated with storing and traveling with the oil.

The bloodstream absorbs the CBD almost immediately, so you experience the relief within 30 to 60 minutes. The effects associated with this method can last four to six hours.

The biggest disadvantage of this method is the taste. Hemp frequently has earthy and natural flavors that are sometimes bitter. You may not like this flavor. You can overcome this with flavored tinctures, but those versions may contain chemicals that you do not want to consume.


Capsules offer a convenient method of consuming CBD for your blood pressure. Capsules come pre-dosed, so you do not have to worry about taking the right amount of cannabidiol. They are also highly convenient and easy to transport.

The effects when taking a capsule are slightly delayed since the capsule has to go through the digestive system before your bloodstream absorbs it. This can take 20 minutes to an hour, depending on your metabolism and what you have recently eaten. However, the results last longer, typically between 6 and 12 hours.


When most people think of cannabis edibles, they picture homemade items, but you can find pre-dosed CBD edibles with or without the THC content. These are most commonly found in the form of gummies, but you can find other options, as well. Each gummy, or another item, have a pre-dosed amount, taking out the guesswork.

Edibles are similar to CBD capsules but are in a different form. You have to wait about 20 minutes to an hour for the effects to begin, but then they last 6 to 12 hours. The gummies and other CBD edibles are highly transportable and convenient, as well.


For those who want to get the CBD oil into their system as quickly as possible, vapes are the best option. Vaping lets the CBD oil into your bloodstream via your lungs. This allows for quick absorption and feeling the effects within minutes.

The downside of vaping CBD oil is that the effects do not last as long. It lasts between 30 minutes and two hours. However, the good news is that when the dose begins to wear off, you can take a new one almost right away.

The other disadvantage of vaping CBD oil is the difficulty in calculating dosage. Your vape product tells you how much cannabidiol is in every inhale. The issue is that everyone inhales slightly differently. Luckily, you can overcome this with trial and error. Within a few uses of CBD vape oil, you should have a better idea of dosing.

Potential Side Effects of CBD

There are a few potential side effects of CBD, but they are uncommon. The side effects of CBD are much less common than the effects associated with most pharmaceutical medications, especially those treating high blood pressure.

Potential side effects include irritability, nausea, diarrhea, changes in weight, changes in appetite, and fatigue.

Consult Your Doctor First If You Currently Take Medications

If you are currently on any prescription medications, then you should talk to your doctor or pharmacist about potential drug interactions before you take CBD oil. CBD can interact with several types of medications, including antibiotics and antidepressants. To be safe, confirm with your doctor if CBD does not reduce the effectiveness of your current medications or interact with it to cause side effects. You should also talk to your doctor about whether CBD would impact other current medical conditions.

For example, if you take Coumadin, a blood thinner, CBD may increase the level of this medicine in your blood. Additionally, if you take any medication that should not be consumed with grapefruit, CBD may interact with it in the same way as grapefruit would. Both CBD and grapefruit interfere with the same specific enzymes involved in drug metabolism.

Long-Term Safety of CBD Oil for Blood Pressure

Because of the legal gray area regarding CBD, experts need to complete more research on the long-term effects associated with the use of CBD. There has not yet been enough time for researchers to conduct the ideal type of longitudinal studies. One study published in Pharmacology back in 1980 looked at cannabidiol consumption in epileptic patients and healthy volunteers. After a month of taking CBD daily, participants from neither category experienced any serious side effects, health issues, or indications of toxicity.

Recent research is still lacking in this respect. However, there do not seem to be any negative long-term effects of taking CBD oil so far.

Buy Your CBD Oil from a Reputable Source

While CBD oil is safe and you are unlikely to experience side effects, you should keep in mind that the FDA does not regulate it. Instead, the FDA treats it as a supplement.

This means that you are responsible for researching any CBD products you choose to use. Confirm that the company has a solid reputation and look for a certificate of analysis. The best CBD companies have third-party testing information for all of their products, complete with certificates of analysis. Most offer this information on their website in a readily accessible spot. Some may require you to email them for the analysis.

Always look at the certificate of analysis before buying a new product for the first time. This confirms that CBD oil is free from harmful substances, such as heavy metals. It also confirms the ingredients and the quantities of CBD and THC.

Other Health Benefits of CBD Oil

As mentioned, reducing blood pressure is far from the only benefit associated with CBD oil. Pain relief is among the most common, although CBD is also linked with controlling seizures and having anti-inflammatory properties. Here are some of the more important other benefits associated with cannabidiol.

Treating Seizures

CBD can help treat some of the worst types of seizure disorders that exist, including Lennox-Gastaut syndrome and Dravet syndrome, both of which affect children and do not normally respond to traditional medications for treating seizures.

Even the FDA recognizes the ability of CBD to treat seizure disorders. The first cannabis-derived medication it approved is Epidolex, which treats these conditions. That medication contains CBD.

Treating Anxiety and Depression

Those who suffer from anxiety experience relief with CBD. One study showed this effect on public speaking, and there is plenty of anecdotal evidence.

Treating Insomnia

Several different studies indicate that CBD can help those with insomnia fall asleep. It also shows promise with improving the quality of sleep.

Treating Pain

One of the most popular uses of CBD oil is its ability to reduce chronic pain. Animal studies, including one in the European Journal of Pain, show that topically applied CBD can reduce inflammation and pain from arthritis. Other studies show that CBD can reduce neuropathic and inflammatory pain. This is crucial as those are two of the hardest types of pain to treat.

Some countries approved Sativex, an oral spray with CBD and THC. This spray effectively treats the pain associated with multiple sclerosis.

Treating Symptoms Associated with Cancer

There is much overlap between the issues CBD can treat and the symptoms of cancer. As such, CBD does well at treating many symptoms associated with cancer. These include treating vomiting, pain, and nausea. It is particularly useful at relieving nausea from chemotherapy.

Treating Acne

There is also some evidence that CBD can reduce acne. Specifically, CBD reduces the inflammation associated with excessive sebum production. Since excessive production of sebum is a key cause of acne, this can reduce the condition.

Protecting the Brain

Some research indicates that cannabidiol has neuroprotective properties that can help it treat neurological disorders. This is a combination of its ability to treat epilepsy and the pain associated with multiple sclerosis. There is also some early research showing that CBD treatment improves sleep quality and quality of life in patients with Parkinson’s disease. Some test-tube research even indicates it may delay the progression of Alzheimer’s disease.

Preventing Diabetes

CBD successfully reduced inflammation in diabetic mice in one study. It also reduced the diabetes incidence, showing promise in treating diabetes in humans.

May Fight Cancer

Although the research is still very early, there are some signs that CBD may help fight the growth of cancer cells. This applies to both animal studies and test-tube studies. The animal studies specifically showed promise with treating cancer in the lungs, colon, brain, prostate, and breast.

Overcoming Substance Abuse

There is some evidence that using CBD can help those with addiction overcome their substance abuse. A study involving rats showed CBD reduced heroin-seeking behavior and reduced morphine dependence.

The Legality of CBD Oil

Because cannabidiol comes from the cannabis plant, it is natural to wonder whether it is legal. This is actually more complicated than it may seem at first since every state has its own requirements. In most parts of the United States, CBD is perfectly legal — or at least easy to get.

The caveat is that the federal government includes CBD with marijuana as a Substance I drug in terms of regulation. However, the government rarely enforces the law regarding CBD because of its benefits and its lack of psychoactive effects and side effects.

Even more confusing, regulations vary depending on if you have CBD from hemp than CBD from marijuana. The former is legal at the federal level, while the latter is not. Typically, if your CBD does not contain THC, it should be legal, although there are exceptions. CBD oil with less than 0.3 percent THC is also legal in many areas, as the hemp laws apply, not the marijuana laws.

To ensure you do not break any laws, you should spend a few minutes before buying CBD to confirm that it is legal in your state or jurisdiction. If your state only allows medical marijuana, get any documentation required for using CBD before you order it.

Toxic and Non-Toxic Causes of High Blood Pressure

High blood pressure or hypertension is a condition characterized by elevated blood pressure. Although this is frequently defined as a systolic blood pressure greater than 160 mmHg and diastolic blood pressure greater than 95 mmHg, such absolute figures must be interpreted in terms of age and ethnicity.

Toxic Causes of High Blood Pressure Specifics
Corticosteroids Androgens
Mineralocorticoids (including black liquorice)
Disulfram/ethanol interaction
Envenomations Scorpions and spiders (Lactrodectus species, Atrax species)
Human Recombinant Erythropoeitin
Metals Barium, Cadmium, Lead, Lithium, Mercury, Sodium, Thallium
Natural toxins ephedra alkaloids
Non-steroidal anti-inflammatory drugs
Selective serotonin-reuptake inhibitors
Sympathomimetics (includes pure alpha adrenoreceptor agonists) Amphetamines, Caffeine, Clonidine (early stages), Cocaine, Ephedrine, Epinephrine, Ergotamines, Levodopa, Metaraminol, Methoxamine, Monamine Oxidase Inhibitors, Norepinephrine, Oxymetazoline, Phencyclidine, Phenylephrine, Phenylpropanolamine, Pseudoephedrine, Tetrahydralozine
Withdrawal states
Coarctation of the aorta
Essential (idiopathic) hypertension
Hyperadrenergic states Agitation, exercise
Hypertensive disease of pregnancy
Raised intracranial pressure
Renal parenchymal hypertension
Renovascular hypertension


Treatment and Monitoring of Hypertension

Hypertension associated with chronic intoxications is usually mild and resolves with identification and removal of the offending agent. In the case of metal intoxications, specific therapy in the form of chelation may be indicated. Hypertension associated with the majority of acute intoxications is mild and requires no more than simple observation until it resolves.

Hypertension following acute overdose is usually of short duration (hours) and parallels the duration of other clinical features of the intoxication. The blood pressure should be frequently measured, especially during the early phases of the intoxication. In severe cases, especially where parenteral hypotensive agents are in use, continuous monitoring via an arterial line is ideal. Very frequent non-invasive blood pressure measurements are an alternative where such facilities are unavailable.

During the hypertensive period, the patient should be closely observed for evidence of the principal acute complications; aortic dissection, intracranial hemorrhage, left ventricular failure and myocardial infarction. Long-term complications from hypertension of toxic aetiology are rare but may include those resulting from intracranial hemorrhage, acute myocardial infarction and retinal hemorrhage.

Fatoumah Alabdulrazzaq, MD and Gideon Koren, MD, FRCPC, FACMT

July 2012



Many of my pregnant or lactating patients are taking calcium channel blockers (CCBs) for hypertension. How safe is maternal use of CCBs for fetuses and nursing infants?


Generally, CCBs have not been shown to increase teratogenic risk. Information regarding the safety of CCBs during lactation is limited, although they are not likely to pose a risk to the nursing infant.


Bon nombre de mes patientes enceintes ou qui allaitent prennent des inhibiteurs calciques (IC) pour l’hypertension. Dans quelle mesure l’utilisation maternelle des IC est-elle sécuritaire pour le fœtus et les nourrissons allaités?


En règle générale, il n’a pas été démontré que les IC présentaient un risque tératogène. Les renseignements concernant l’innocuité des IC durant l’allaitement sont limités, mais il est improbable qu’ils posent un risque pour le nourrisson allaité.

Calcium channel blockers (CCBs) are commonly used during pregnancy and lactation to treat hypertension, arrhythmia, and preeclampsia. They have also been used as tocolytic agents to prevent premature labour and its complications.

Population-based data from 5 health maintenance organizations in the United States were used to study the risks of perinatal complications and congenital defects among infants exposed in utero to CCBs or ß-blockers. Calcium channel blocker use in the third trimester was associated with increased risk of neonatal seizures, jaundice, and hematologic disorders (relative risk [RR] 3.6, 95% CI 1.3 to 10.4). The risk of neonatal convulsions was in part attributed to the placental transfer of CCBs, leading to a decrease in infants’ cellular calcium levels.1 There was no increase in risk of congenital anomalies in either group of infants. The risk of one or more malformations was not elevated in the group of infants exposed to CCBs (RR 0.96, 95% CI 0.47 to 1.97). 1

The Motherisk program reported no increased teratogenic risk of perinatal complications among 78 women exposed to CCBs in the first trimester. Maternal hypertension was the most important factor responsible for babies with low birth weights in this group. 2

The Swedish Medical Birth Register studied a cohort of 1418 pregnancies in which the mothers took anti-hypertensive drugs in early pregnancy; in 217 pregnancies, the mothers took CCBs. Three babies were born with congenital heart defects (RR 1.15). The study concluded that there was little drug specificity in the association between maternal use of antihypertensive drugs and increased risk of infant cardiovascular defects. 3

A Hungarian case-control study identified 22 865 infants with congenital abnormalities and 31 151 healthy population control babies between 1980 and 1996; 586 mothers had been exposed to CCBs during pregnancy compared with 907 mothers in the control group. The overall prevalence ratios for 17 congenital abnormalities varied between 1.1 and 1.4, and there was no significant increase in risk of congenital abnormalities. 4

All CCBs pass into the breast milk in small amounts. 5-7 Both LactMed (Drugs and Lactation Database) and the American Academy of Pediatrics conclude that this class of medications is compatible with breastfeeding. 8 It is advisable to follow up with any exposed infant for signs of hypotension.

Calcium channel blockers can be safely used during pregnancy and breastfeeding.

CAS # 92-52-4 C12H10 / C6H5C6H5
RTECS # DU8050000 Molecular mass: 154.2
UN # 3077

EC # 601-042-00-8

Physical properties:

Boiling point: 256°C
Melting point: 70°C
Relative density (water = 1): 1.04
Solubility in water: none
Vapour pressure, Pa at 71°C: 133
Relative vapour density (air = 1): 5.3
Relative density of the vapour/air-mixture at 20°C (air = 1): 1.0
Flash point: 113°C c.c
Auto-ignition temperature: 540°C
Explosive limits, vol% in air: 0.6 (at 111°C) – 5.8 (at 166°C)
Octanol/water partition coefficient as log Pow: 3.16/4.09

Biphenyl is combustible. No open flames should be in close proximity. Finely dispersed particles form explosive mixtures in air. Prevent deposition of dust; closed system, dust explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding).

Biphenyl can be absorbed into the body by inhalation and by ingestion. Prevent dispersion of dust. Avoid inhalation of fine dust and mist. Use local exhaust or breathing protection.

Protect the skin. Wear protective gloves. Remove contaminated clothes. Rinse and then wash skin with water and soap. Do not take working clothes home.

Biphenyl may cause redness and pain in the eyes. Prevention include safety goggles or eye protection in combination with breathing protection if powder. In case of contamination, first rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.

For spillage disposal, sweep spilled substance into sealable containers; if appropriate, moisten first to prevent dusting. Carefully collect remainder, then remove to a safe place. Personal protection: A/P2 filter respirator for organic vapour and harmful dust. Do not let this chemical enter the environment.

For safety storage, keep separated from food and feedstuffs, oxidants. For packaging and labelling, do not transport with food and feedstuffs.

Biphenyl can be absorbed into the body by inhalation and by ingestion. Physical dangers of Biphenyl include dust explosion possible if in powder or granular form, mixed with air. A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20°C. Chemical dangers of Biphenyl include how it reacts with oxidants. Effects of short-term exposure: The substance is irritating to the eyes and the respiratory tract. Effects of long-term exposure: The substance may have effects on the liver and nervous system, resulting in impaired functions.

Biphenyl may be hazardous to the environment; special attention should be given to water quality. Bioaccumulation of this chemical may occur along the food chain, for example in plants. It is strongly advised not to let the chemical enter into the environment because it persists in the environment.


Taking angiotensin-converting enzyme inhibitors during pregnancy – Is it safe?

Almundher Al-Maawali, MD, Asnat Walfisch, MD and Gideon Koren, MD, FRCPC, FACMT

January 2012



One of my 35-year-old pregnant patients has been treated with enalapril for primary hypertension. She learned she was pregnant at 11 weeks’ gestation. I read somewhere that angiotensin-converting enzyme (ACE) inhibitors can cause malformations. What advice do you give to Motherisk callers?


Most published studies have failed to show an effect of ACE inhibitors on congenital malformations. A recent systematic review and meta-analysis conducted by Motherisk does not suggest increased fetal risk of malformations. However, ACE inhibitors should be avoided in late pregnancy, as they might cause renal failure and acalvaria in the baby.


L’une de mes patientes enceintes âgée de 35 ans est traitée avec de l’énalapril pour une hypertension primaire. Elle a appris qu’elle était enceinte après 11 semaines de gestation. J’ai lu quelque part que les inhibiteurs de l’enzyme de conversion de l’angiotensine (ECA) peuvent causer des malformations. Quels conseils donnezvous à ceux qui posent des questions à ce sujet à Motherisk?

La plupart des études publiées n’ont pas réussi à révéler des effets attribuables aux inhibiteurs de l’ECA sur les malformations congénitales. Une récente synthèse critique et une méta-analyse réalisées par Motherisk n’indiquent pas qu’il puisse y avoir des risques fœtaux accrus de malformations. Toutefois, il faudrait éviter les inhibiteurs de l’ECA en fin de grossesse, car ils pourraient causer une insuffisance rénale et l’absence de voûte crânienne chez le bébé.


Essential hypertension is a common diagnosis among young women.1 Depending on the population studied, the incidence during pregnancy ranges from 0.5% to 3.0%.2 Different types of hypertensive disorders during pregnancy include chronic hypertension, gestational hypertension, and preeclampsia, accounting for most antenatal care provision.3 Risks to the mother include maternal death, stroke, heart failure, and pulmonary edema. The fetus is also at risk, and common fetal complications include intrauterine growth restriction, placental abruption, and prematurity.4

Angiotensin-converting enzyme (ACE) inhibitors are widely used as first-line therapy for chronic hypertension. They are frequently used in women of reproductive age; consequently, some women are bound to be taking ACE inhibitors at the time of conception, as more than half of all pregnancies are unplanned.4

Captopril, enalapril, and lisinopril cross the human placenta in pharmacologically significant amounts. It is conceivable that other ACE inhibitors have similar placental transfer.5,6

Animal studies

While the results of animal studies on the use of ACE inhibitors during pregnancy vary, most of them have failed to show increased malformation rates. However, animal data reveal increased morbidity and mortality in fetuses exposed to ACE inhibitors in utero. A prospective placebo-controlled study of baboons showed a significant increase in fetal death or fetal growth restriction (4 of 13) in the group treated with enalapril when compared with placebo (P < .05).7 Use of captopril in maternal sheep during late pregnancy caused low fetal blood pressure, and the risk of stillbirth was substantially elevated.8

First-trimester human exposure

Cooper and colleagues9 reported an increased risk of congenital malformations in fetuses exposed to ACE inhibitors during the first trimester. They studied a cohort of 29 507 infants who were enrolled in Tennessee Medicaid, who were born between 1985 and 2000, and for whom there was no evidence of maternal diabetes. Out of this cohort, 209 infants with exposure to ACE inhibitors in the first trimester were identified. The risk ratio for major congenital malformations was 2.71 (95% 1.72 to 4.27). It has been argued that these findings were affected by confounding and ascertainment biases. These include the inability to exclude women with undiagnosed or diet-controlled type 2 diabetes mellitus, no adjustment for prepregnancy body mass, which is a considerable predictor of risk of type 2 diabetes mellitus, and uncontrolled hypertension.10 In infants, maternal obesity is an independent risk factor for neural tube defects and cardiac malformations.11,12

Recently, Motherisk13 conducted a systematic review of the literature and meta-analysis evaluating the use of ACE inhibitors during the first trimester of pregnancy and their association with major congenital malformations. We identified 5 cohort studies for the meta-analysis and included 19 case reports, case series, or case-control studies in the descriptive part of the systematic review. The meta-analysis failed to demonstrate an increase in major malformations after use of ACE inhibitors or angiotensin II receptor blockers (ARBs) specifically, with no difference from exposure compared with other antihypertensive medications. The systematic review of the case reports and case series published in the past 25 years involved 424 pregnancies. These reports do not suggest a specific pattern of malformations.

Diav-Citrin et al recently studied 252 pregnancies exposed to ACE inhibitors and ARBs, 256 pregnancies exposed to other antihypertensive medications, and 495 control pregnancies from 2 teratology information services in Israel and Italy. They concluded that ACE inhibitors and ARBs are not major teratogens when used in the first trimester, and the risk of major congenital malformations was comparable between the groups (P = .95). In this study, women with known diabetes (both preexisting and gestational) were not excluded, and there was no adjustment for maternal body mass index.14

Serreau et al reported on 10 cases of pregnant women exposed to ARBs during early pregnancy. One out of the 8 fetuses exposed exclusively during the first trimester was reported to have craniofacial dysmorphia, clinodactyly, and tubular dysplasia.15

In a cohort retrospective review of 348 989 infants or fetuses from all pregnancies in Finland (N = 343 324), exposure of infants or fetuses to ACE inhibitors (n = 137) was associated with an increased risk of major congenital malformations, mostly cardiac. However, when adjusted for diabetes, the excess risk was nullified.16

Lennestål et al17 reported on a cohort of 1418 women from the Swedish Medical Birth Register who had used antihypertensive drugs in early pregnancy but who did not have diabetes. Cardiovascular defects occurred with an adjusted odds ratio of 2.59 (95% CI 1.92 to 3.51). However, the results were similar when the women had used ACE inhibitors or other antihypertensive drugs, without any clear drug specificity.

In France, data on 159 pregnancies with exposure to ACE inhibitors and 159 controls were obtained. Pregnancies with confirmed first-trimester exposure to ACE inhibitors were included. The rate of major malformations in live births or stillbirth was not different between the 2 groups (relative risk 1.5, 95% CI 0.3 to 6.5).18

Second and third trimesters

Second- and third-trimester exposure to ACE inhibitors is associated with oligohydramnios, hypocalvaria, anuria, renal failure, neonatal hypotension, and patent ductus arteriosus.1921 It is also associated with aortic arch obstructive malformations.22 Some of these infants exhibit severely impaired renal function and hypoplastic lungs owing to oligohydramnios, and they might progress to death or end-stage renal failure. The cause of these defects appears to be related to inhibitory effects on the renin-angiotensin-aldosterone system.23 The morbidity is estimated to be quite high; it is between 10% and 20% of infants exposed.4



Taking ACE inhibitors during pregnancy:Is it safe?

Savithiri Ratnapalan, MB BS, MRCP Gideon Koren, MD, FRCPC

June, 2002



A pregnant patient is taking enalapril for primary hypertension. How safe are angiotensin-converting enzyme inhibitors (ACEI) during pregnancy?


Evidence of whether ACEIs cause problems during the first trimester of pregnancy is reassuring. There is evidence that they cause severe renal and other problems during the second and third trimesters, however. These drugs should be avoided during pregnancy.


Une patiente enceinte prend de l’énalapril pour une hypertension primaire. Les inhibiteurs de l’enzyme de conversion de l’angiotensine (IECA) sont-ils sans risque durant la grossesse?


Les données probantes à savoir si les IECA causent des problèmes durant le premier trimestre de la grossesse sont rassurantes. Par ailleurs, il est démontré qu’ils causent de graves problèmes néphrologiques et d’autres problèmes durant le deuxième et le troisième trimestres. Ces médicaments devraient être évités durant la grossesse.


Incidence of chronic hypertension during pregnancy ranges from 0.5% to 3.0% depending on the population studied.1 Maternal and perinatal morbidity and mortality are generally not increased when patients have uncomplicated mild chronic hypertension. Risks to both mother and fetus increase dramatically, however, when pregnancy is complicated by severe uncontrolled hypertension or other risk factors, such as older maternal age, hypertension lasting more than 15 years, diabetes, renal disease, cardiac disease, or connective tissue disease.1 Some reported complications of uncontrolled hypertension during pregnancy are maternal death, stroke, heart failure, and pulmonary edema; common fetal complications are intrauterine growth restriction, abruption of the placenta, and prematurity and its adverse effects.1

Angiotensin-converting enzyme inhibitors are excellent antihypertensive agents with few side effects (Table 1). They are becoming widely used as first-line therapy for chronic hypertension in women of reproductive age. They are also used in treatment of renovascular hypertension, autoimmune diseases, and diabetes mellitus in this age group. Because 50% of all pregnancies are unplanned, some women are bound to be taking ACEIs at the time of conception.

Animal studies
Animal studies of rats and rabbits given ACEIs during organogenesis showed no increased incidence of major malformations in offspring. Animal data reveal, however, increased morbidity and mortality in fetuses exposed to ACEIs in utero. Decreased uteroplacental blood flow, low birth weight, hypotension, preterm delivery, and fetal death were noted.2 A prospective placebo-controlled study of baboons showed a significant increase in fetal death or fetal growth restriction (four of 13) in the group treated with enalapril compared with no instances among the controls.3

Placental transfer
Captopril, enalapril, and lisinopril have been shown to cross the human placenta in pharmacologically significant amounts; other ACEIs probably do the same.4-6 Once in a fetus, most ACEIs are excreted renally in their active form (when there is urine production) and could be recirculated through swallowed amniotic fluid.




Taking ACE inhibitors during early pregnancy

Joel G. Ray, MD MSc FRCPC, Marian J. Vermeulen, MHSc and Gideon Koren, MD FRCPC

September 2007



I knew that angiotensin-converting enzyme (ACE) inhibitors were risky to use during late pregnancy because they can cause renal shutdown in the fetus. Recently I heard of a study that claimed first-trimester exposure (when many patients still are unaware of their pregnancies) can also cause major malformations. Is this proven?


A recent study did suggest an increased risk of malformations after first-trimester exposure to ACE inhibitors among women treated for hypertension. We believe this study had serious limitations that preclude drawing any conclusions at present.


It is well accepted that angiotensin-converting enzyme (ACE) inhibitors are contraindicated during the second and third trimesters of pregnancy because of increased risk of fetal renal damage. First-trimester use, however, has not been linked to adverse fetal outcomes.

Cooper and colleagues conducted a study to assess the association between exposure to ACE inhibitors during the first trimester of pregnancy and risk of congenital malformations. 1 They followed a cohort of 29 507 infants from Tennessee Medicaid files who were born between 1985 and 2000 and whose mothers had no evidence of having had diabetes. The researchers identified 209 infants who had been exposed to ACE inhibitors during the first trimester only, 202 infants who had been exposed to other antihypertensive medications during the first trimester only, and 29 096 infants who had not been exposed to antihypertensive drugs. Infants who had been exposed to ACE inhibitors had a greater risk of major congenital malformations (risk ratio 2.71, 95% confidence interval [CI] 1.72 to 4.27) than did infants not exposed to antihypertensive medications. Being exposed to other antihypertensive medications did not result in an increased risk of major malformations (risk ratio 0.66, 95% CI 0.25 to 1.75). Infants exposed to ACE inhibitors were at increased risk of malformations of the cardiovascular system (risk ratio 3.72, 95% CI 1.89 to 7.30) and the central nervous system (risk ratio 4.39, 95% CI 1.37 to 14.02). The authors concluded that exposure to ACE inhibitors during the first trimester cannot be considered safe and should be avoided.

Clarence Swader

Clarence is a medical marijuana patient, writer, and hiking enthusiast who spends most of his time outdoors. He loves nature and is continuously trying to discover and write about its benefits for general health.
Clarence Swader

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