Benazepril is a prescription medication used primarily to treat high blood pressure. Sold under the brand name Lotensin, it belongs to a class of drugs called ACE inhibitors that work by relaxing blood vessels and reducing the workload on your heart. It’s FDA-approved for hypertension in adults and children aged 6 and older, and it’s also widely used off-label to protect kidney function in people with chronic kidney disease.
How Benazepril Lowers Blood Pressure
Your body has a built-in system for regulating blood pressure that involves a chain reaction of hormones. One key step in that chain is the conversion of a relatively inactive substance (angiotensin I) into a powerful one (angiotensin II) that tightens blood vessels and signals your kidneys to retain salt and water. Benazepril blocks the enzyme responsible for that conversion.
The result is twofold: your blood vessels relax, and your body holds onto less fluid. Both effects lower blood pressure. A single dose keeps working for about 24 hours, which is why most people take it once a day. The active form of the drug has an effective half-life of 10 to 11 hours, and steady blood levels are typically reached after two or three daily doses.
Protecting the Kidneys
Beyond blood pressure control, benazepril and other ACE inhibitors have a well-established role in slowing kidney damage. National Kidney Foundation guidelines recommend ACE inhibitors as preferred agents for both diabetic and nondiabetic kidney disease that involves protein leaking into the urine (proteinuria). In clinical trials, ACE inhibitors reduced protein loss by roughly 35% to 40%, a benefit that goes beyond what blood pressure reduction alone would explain.
The reason appears to be local: ACE inhibitors lower pressure inside the tiny filtering units of the kidney, not just in the bloodstream at large. That reduced internal pressure slows the scarring process that leads to progressive kidney failure. Guidelines support using ACE inhibitors for this purpose even in people whose blood pressure is otherwise normal.
Role in Heart Failure
ACE inhibitors as a class are a cornerstone of heart failure treatment, particularly when the heart’s pumping ability is reduced. A large network meta-analysis published in the American Heart Association’s journals found that ACE inhibitors alone were associated with roughly a 16% reduction in death compared to placebo. When combined with beta-blockers and a type of hormone-blocking drug, that reduction jumped to 56%. Newer combination regimens have pushed the benefit even further, but ACE inhibitors remain a foundational part of treatment for many patients with heart failure.
Common Side Effects
The most well-known side effect of ACE inhibitors, including benazepril, is a persistent dry cough. This happens because the same enzyme benazepril blocks is also involved in breaking down bradykinin, a substance that can irritate airways. The cough is harmless but can be annoying enough that some people switch to a different class of blood pressure medication. Reported rates of this cough vary widely across studies.
Other possible side effects include dizziness (especially when standing up quickly), elevated potassium levels, and, less commonly, swelling of the lips, face, or throat. That swelling, called angioedema, is rare but requires immediate medical attention.
Pregnancy Warning
Benazepril carries an FDA black box warning, the most serious category, regarding use during pregnancy. The drug can cause severe harm to a developing fetus, including kidney failure, underdeveloped lungs, skull abnormalities, and death. These risks are highest during the second and third trimesters. If you become pregnant while taking benazepril, it should be stopped as soon as possible.
Important Drug Interactions
Two interactions are especially worth knowing about. Common pain relievers like ibuprofen and naproxen (NSAIDs) can blunt benazepril’s blood pressure-lowering effect and, in some cases, worsen kidney function. This risk is higher in older adults, people who are dehydrated, or anyone with existing kidney problems. The effects are usually reversible, but kidney function should be monitored if you’re regularly using both.
Potassium is the other concern. Because benazepril causes your body to retain potassium, combining it with potassium supplements or potassium-sparing water pills can push levels dangerously high. Elevated potassium affects heart rhythm, so periodic blood tests are standard for anyone on benazepril.
Typical Dosing
For adults, the usual starting dose is 10 mg once daily, with a maintenance range of 20 to 40 mg per day taken as one dose or split into two. People already on a diuretic (water pill) typically start at 5 mg to avoid a sudden drop in blood pressure. The maximum evaluated dose is 80 mg per day, though experience at that level is limited.
For children 6 and older, the starting dose is weight-based at 0.2 mg per kilogram of body weight once daily, which can be increased up to 0.6 mg per kilogram (not exceeding 40 mg). Benazepril is not recommended for children under 6 or for children with significantly reduced kidney function.
Adults with reduced kidney function also start at a lower dose of 5 mg daily and can be increased as needed up to 40 mg, with closer monitoring of blood work along the way.