Key takeaways
Benazepril starts working within 30 minutes to an hour of taking your first dose.
The majority of the medication leaves your system within 24 hours and is totally processed within two days.
Several factors affect how long benazepril remains in the body, including age and kidney and liver function.
Benazepril is a common angiotensin-converting enzyme inhibitor (ACE inhibitor). It’s used to decrease high blood pressure, a condition that, when untreated, can damage the heart and arteries, increasing your risk of stroke, heart attacks, heart failure, kidney disease, and kidney failure. Also sold under the brand name Lotensin, it works by blocking a chemical that makes your blood vessels tighten. After you take your first dose, it starts working quickly, in just 30 minutes to one hour. Peak blood-pressure-lowering effects occur within two hours, though it may take a few days of use for your blood pressure readings to change. Most of a benazepril dose is processed out of your system within 24 hours, though trace amounts can remain for nearly two days. However, the timeline can vary depending on certain individual factors.
How long does benazepril stay in your system?
For healthy individuals who aren’t taking any other medications, benazepril is typically completely eliminated from the body within two days. The length of time a medication remains in your system depends on the half-life, or the time it takes for half of the drug to be processed. It’s common for medications to stay in your body for four half-lives, says Joyce Oen-Hsiao, MD, an associate professor of medicine at Yale School of Medicine and director of Cardiac Rehabilitation Services at Yale-New Haven Hospital Heart & Vascular Center.
“Benazepril has a half-life of 10 to 11 hours, so to be completely out of your system would take about 40 hours,” Dr. Oen-Hsiao said. “The majority of the benazepril, about 90%, is out of the system within 24 hours.”
After you take a benazepril dose, the drug begins working quickly—in just 30 minutes to an hour, Dr. Oen-Hsiao says. It becomes detectable in blood tests within one to two hours of taking the medication, though blood pressure readings may take a few days to lower.
Factors that influence how long benazepril stays in your system
It’s important to know how your body processes benazepril because it can affect how well the medication works, how often you take the medication, and when you are likely to experience side effects or drug interactions. Certain things can affect how quickly it leaves your body, including:
Kidney and liver function
Kidney and liver function play a significant role in how long benazepril remains in the system. “Since the liver is what metabolizes benazepril, poor liver function can cause higher levels of benazepril not metabolized to remain in the system,” Dr. Oen-Hsiao says. Your healthcare provider may need to adjust benazepril’s dosage if you have kidney problems or liver failure.
Age
How your body processes benazepril changes as you age. One study found that older individuals experience a slightly longer half-life. This means benazepril stays in the body longer at the same dosage.
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Side effects and risks of benazepril
As with any medication, there are potential side effects of taking benazepril, though the medication is often well-tolerated with minimal or no side effects. The most common side effects of benazepril are low blood pressure (hypotension), headaches, and a dry cough. Anywhere between 5% and 35% of individuals taking ACE inhibitors like benazepril experience a dry cough.
Other possible benazepril side effects include:
- Anxiety
- Asthma and bronchitis
- Changes in urination amount and frequency
- Decreased libido
- Dizziness
- Elevated potassium level (hyperkalemia)
- Gastrointestinal symptoms
- Hair loss
- Insomnia
- Lightheadedness and fainting
- Low blood counts
- Muscle pain and arthritis
- Sinusitis
Serious side effects may include allergic reactions, fainting, angioedema (swelling of the face, lips, tongue, throat, or fingers), abdominal pain, and severe skin rashes, blistering, peeling, or loosening of the skin (known as Stevens-Johnson Syndrome).
Some drug interactions that can impact the safety of taking benazepril include:
- Diuretics, such as furosemide, can reduce blood pressure too much (leading to dizziness) when taken with benazepril.
- Potassium-sparing diuretics, like spironolactone, can cause high potassium levels (hyperkalemia) that can affect cardiovascular and muscle function when coadministered with benazepril.
- Diabetes medications, such as insulin, can reduce a person’s blood sugar when taken with benazepril, leading to dizziness and fainting.
- Nonsteroidal antinflammatory drugs (NSAIDs), like ibuprofen, can reduce kidney function.
This is not a complete list of interactions. Always share a list of all over-the-counter medications and supplements you are taking with your pharmacist and provider.
You should not take benazepril at any time during pregnancy because it can cause fetal malformations, according to the U.S. Food and Drug Administration (FDA). However, a study found that benazepril is safe to take while breastfeeding because very little of the metabolized drug is excreted into human breast milk.
How long does it take for side effects to go away after stopping benazepril?
Side effects lessen as benazepril is processed out of your body, within two days of your last dose.
“Since benazepril as a rule has mild adverse effects with little risk in the way of lasting tissue damage or other outcomes, most side effects will dwindle in tandem with the declining blood concentration of the drug, also within a day or two of halting the doses and discontinuing a prescription,” explains J. Wes Ulm, MD, Ph.D., a biomedical data specialist with the National Institutes of Health.
Some side effects may take a little longer to completely diminish. For example, if you experience a dry cough, it will typically clear within one to four weeks after stopping benazepril, says Dr. Oen-Hsiao. “Acute kidney injury and hyperkalemia, if caught early, can resolve within a week of stopping the benazepril,” she says.
Tapering schedule and discontinuation
Despite the low risk of serious side effects, some patients may experience issues that could affect quality of life, including a persistent cough or dizziness. Others may find their health has improved to the point where they no longer need the medication.
Stopping the drug altogether, or “cold turkey,” can lead to complications, says Michael Chichak, MD, a general practitioner at MEDvidi. One of these complications is rebound hypertension, which is a sudden increase in blood pressure that can lead to health risks like a heart attack or stroke. Rather, your provider will decrease your dose gradually to avoid issues.
The typical schedule involves cutting the dose by half over three to five days until the dose is low enough to stop completely, Dr. Oen-Hsiao says. There are generally few withdrawal symptoms from stopping benazepril.
“There are some reports of anxiety, nausea or vomiting, and tremors,” Dr. Oen-Hsiao says. “However, these are not common. The medication is mostly out of the system within 24 hours, so any symptoms should improve by then.”
Benazepril alternatives
If a patient cannot tolerate benazepril, the most common alternative is another ACE inhibitor, such as quinapril, captopril, lisinopril, or enalapril. The second-line option is switching to an angiotensin receptor blocker (ARB), such as losartan or valsartan, Dr. Oen-Hsiao says.
ACE inhibitors lower blood pressure by blocking the angiotensin-converting enzyme (ACE). However, this enzyme also breaks down bradykinin, a substance that can cause a cough when it builds up. ARB medications block the action of angiotensin II, a hormone that constricts blood vessels without the bradykinin effects that cause a dry cough.
There are several other antihypertensive drugs available, including:
- Thiazide diuretics like hydrochlorothiazide
- Beta blockers such as atenolol, carvedilol, bisoprolol, or metoprolol
- Calcium-channel blockers like nifedipine and amlodipine
- Central agonists such as methyldopa and clonidine
- Other vasodilators like hydralazine and minoxidil
- Alpha 1-receptor blockers such as prazosin and doxazosin
If side effects interfere with everyday life, it’s important to talk to a healthcare provider, Dr. Oen-Hsiao says. Although most patients tolerate ACE inhibitors well, Dr. Oen-Hsiao always works with the patient to find a solution.
“In general, you were prescribed the medication for a reason,” she says. “The provider will be able to substitute a different medication to help with your medical conditions. Stopping the medication without consulting a healthcare provider could potentially cause medical harm, as the medical condition is no longer being treated.”
- ACE Inhibitor and Angiotensin Receptor Blocker Use During Pregnancy: Data From the ESC Registry Of Pregnancy and Cardiac Disease, The American Journal of Cardiology (2024)
- Angiotensin-converting enzyme inhibitor-induced cough: ACCP evidence-based clinical practice guidelines, National Library of Medicine (2006)
- Benazepril, National Library of Medicine (2024)
- Benazepril (oral route), Mayo Clinic
- Lotensin drug label, U.S. Food and Drug Administration
- Pharmacokinetics and pharmacodynamics of the ACE inhibitor benazepril hydrochloride in the elderly, European Journal of Clinical Pharmacology (1990)