Benazepril: dosage, side effects, and interactions

If you’ve been diagnosed with high blood pressure, you may be prescribed benazepril.

Benazepril is an ACE inhibitor, a type of drug that keeps blood vessels dilated and relaxed. Think of your blood vessels like a highway. An ACE inhibitor like benazepril essentially converts a two-lane highway to an eight-lane, reducing traffic and letting your blood flow more freely.

ACE inhibitors also remove some of the fluid from your bloodstream, lowering your blood volume and further reducing blood pressure (Herman, 2020). 

Depending on your circumstances, benazepril may be prescribed alone or with other treatments. It’s common for drugs like this to be combined with other blood pressure medications as that’s usually more effective than just one drug on its own.

A typical starting dose for adults with high blood pressure is 5 mg per day (if prescribed along with a diuretic or water pill) or 10 mg per day without a diuretic. Combined treatment dosages are often lower to prevent the risk of developing low blood pressure, which can cause dizziness or even fainting. 

After starting treatment, a healthcare provider will likely monitor your response to the medication and increase the dosage or change treatment as needed. 

The dosage is typically the same in older patients but may be reduced to 5 mg daily if kidney problems exist. The kidneys are what process medications like benazepril and remove them from your body. If your kidneys aren’t working well, it can result in higher drug levels in the bloodstream than intended.

If there’s any concern about how well your kidneys are working, a healthcare professional can do a blood or urine test to check.

Keep in mind that it can take up to a week for the full effects of benazepril to appear. In addition to high blood pressure, it’s effective in treating congestive heart failure and reducing heart attack and stroke risk. Benazepril can also help with kidney problems related to diabetes and is sometimes used to treat or prevent migraine headaches. 

Benazepril is typically taken once or twice daily. What dosage you need depends on factors—like age or pre-existing health conditions—which we’ll get into more below.

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Generally, benazepril is considered to be a safe, effective, and well-tolerated drug. This medication comes as an oral tablet and is available in doses of 5 mg, 10 mg, 20 mg, and 40 mg.

It’s common for adults to start with a dose of either 5 or 10 mg once a day. However, those taking other medications (like diuretics, as we mentioned earlier) may start at a lower dose (FDA, 2014).

Once your body gets accustomed to the medication, you’ll usually take between 20 mg and 40 mg to keep blood pressure levels under control. Benazepril can be taken as a single dose or split into two equal doses per day. This medication hasn’t been deemed safe for children younger than six (FDA, 2014).

Do not take benazepril if you are pregnant or think you might be. Benazepril carries a black box warning from the U.S. Food and Drug Administration (FDA)—the most serious warning.This medication is toxic to a developing fetus and can cause severe injury or death. Stop taking benazepril immediately if you discover you’re pregnant (FDA, 2014).

If you have any of the following health problems, you may be at higher risk for adverse reactions taking benazepril:

• Heart disease 

• History of heart attacks

• Kidney disease

• Liver disease

• Angioedema 

The drug’s most common side effects include dry cough, dizziness, fatigue, headache, and nausea. 

Serious side effects are rare but can happen. Liver failure, angioedema (rapid swelling of the face and neck), low blood pressure, high potassium, and other severe allergic reactions have occurred while taking this medication (Dahal, 2020). 

Whether you’re taking benazepril on its own or with other blood pressure medications, it’s always a good idea to familiarize yourself with any potential drug interactions that could occur.

There are hundreds of medications or supplements benazepril is known to react with, but here are some of the most common ones known to interact with benazepril (FDA, 2014):

• Medications for diabetes: If you’re taking medications to treat diabetes (like insulin, for example), use caution when mixing with benazepril as the combination could cause hypoglycemia, or low blood sugar. 

• Medications that affect : Mixing benazepril with any medications or supplements containing potassium could lead to hyperkalemia, or high potassium levels in the blood.

• Diuretics: Diuretics, also called water pills, help reduce blood pressure by encouraging your body to get rid of water and salt. Combining diuretics with benazepril may also cause your blood pressure to drop too low. Your healthcare provider may recommend a lower dose of each if you’re taking both medications.

• Non-steroidal anti-inflammatory drugs (NSAIDs): Taking benazepril at the same time as NSAIDs may reduce the effectiveness of benazepril, and affect kidney function in certain patients. 

• Other drugs that block the renin-angiotensin system (RAAS): Benazepril is a RAAS inhibitor but there are also other medications in this class that can be used to treat high blood pressure. Using other RAAS inhibitors alongside benazepril increases the risk for reactions like low blood pressure, high blood potassium levels, and impaired kidney function.

• mTOR inhibitors: These medications are mainly used for treating cancer, and can trigger angioedema if combined with benazepril.

• Lithium: Lithium is commonly used to treat mood disorders. Use caution when taking benazepril, as ACE inhibitors can lead to lithium toxicity in the body.

• Gold: While not as common, benazepril can cause a nitritoid reaction (signs of this include facial flushing, hypotension, nausea, and vomiting) for people getting injectable gold therapy.

There’s no cure for high blood pressure, but with the proper medication and a heart-healthy lifestyle, you can manage this condition. By keeping up with exercise, eating a well-balanced diet, and cutting back on habits like smoking or alcohol use, you can protect yourself from more serious health problems in the future (Tsai, 2020).

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

April 08, 2021

Written by

Anna Brooks

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.