Drug Detail:Benazepril (Benazepril [ ben-ay-ze-pril ])
Drug Class: Angiotensin Converting Enzyme Inhibitors
1. How it works
- Benazepril is a medication that may be used to treat high blood pressure and other conditions related to the heart.
- Benazepril works by inhibiting an enzyme called angiotensin-converting enzyme. This enzyme is involved in the production of angiotensin II, a powerful vasoconstrictor (narrows arteries), which also stimulates the release of the hormone aldosterone from the adrenal glands (aldosterone increases blood pressure). By inhibiting this enzyme, benazepril opens up the arteries (vasodilates) and lowers blood pressure.
- Benazepril belongs to a group of medicines known as angiotensin-converting enzyme (ACE) inhibitors.
2. Upsides
- Benazepril may be used to lower blood pressure in people with high blood pressure (hypertension). Lowering blood pressure reduces the risk of fatal and nonfatal cardiac events, including strokes and heart attacks.
- May be used off-label for several other conditions, such as heart failure, non-ST-elevation, ST-elevation acute coronary syndrome, and stable coronary artery disease. Many of these uses are supported by national and international guidelines.
- Effective alone or in combination with other treatments for high blood pressure.
- ACE inhibitors, such as benazepril, are recommended by guidelines as one of the preferred agents for the initial management of hypertension. They may be preferred in hypertensive patients with heart failure, ischemic heart disease, diabetes mellitus, chronic kidney disease, cerebrovascular disease, or with a history of myocardial infarction (heart attack).
- May be given as a single dose once daily or split into two doses. Divided dosing of benazepril has been more effective at controlling pre-dose blood pressure.
- Approved to treat high blood pressure in children aged 6 years and older.
- A 2mg/mL oral suspension may be made by mixing 15 benazepril 20mg tablets in an amber bottle with 75mL of Ora-plus. Shake for two minutes then allow to stand for at least an hour, then shake again for at least one minute. Sweeten with 75mL Ora-Sweet and shake again. Put on the label "shake well" and "refrigerate". Stable for 30 days.
- May be taken with or without food.
- Available in a fixed combination preparation with either hydrochlorothiazide or amlodipine. Fixed combinations should not be used for initial therapy.
- Generic benazepril is available.
3. Downsides
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- A headache and cough are the most common side effects. The cough usually resolves on discontinuation of therapy and is a side effect common to all ACE inhibitors.
- Dizziness, tiredness, and postural hypotension (rapid lowering of blood pressure when going from a sitting or lying down position to standing) are also common.
- Occasionally, lowering of blood pressure may be excessive. The risk is higher in those on diuretic therapy or who are sodium-depleted or dehydrated.
- Rarely may cause angioedema of the face, lips, tongue, throat, and extremities. May occur at any time during treatment. Immediate discontinuation is warranted if angioedema is affecting breathing.
- Also rare is the development of blood disorders and kidney and liver failure.
- May increase blood potassium levels (hyperkalemia); the risk is higher in people with diabetes, poor kidney function, and in people using potassium-sparing diuretics or taking potassium supplements.
- May have less of a blood pressure-lowering effect in patients of African-American descent compared to those without this ethnicity. Also, the incidence of angioedema (skin reaction associated with head and neck swelling) is higher in African-American patients. These patients tend to respond better to monotherapy with calcium channel blockers or thiazide diuretics.
- Should not be used by women who are pregnant or at risk of pregnancy because it may cause injury or death to the developing fetus. Ensure women of childbearing age use adequate contraception to prevent pregnancy. If pregnancy inadvertently occurs, discontinue benazepril immediately.
- May not be suitable for some people such as those with previous hypersensitivity to benazepril and other ACE inhibitors, a history of angioedema, with diabetes who are also taking aliskiren, or within 36 hours of switching to or from a neprilysin inhibitor, such as sacubitril.
- Benazepril can interact with several other medications (including NSAIDs and lithium) - consult your prescribing doctor before taking any other medications including those brought over the counter.
- The dosage of benazepril may need to be reduced in people with kidney disease.
- During the initiation of benazepril, blood pressure should be monitored regularly (such as monthly), and the dosage of benazepril adjusted if needed. The usual starting dosage of benazepril is 10mg once a day in people not already receiving a diuretic or 5mg initially in people already receiving a diuretic.
- If adequate blood pressure control is not achieved with a single agent, such as benazepril, then either increase the dosage or add a second drug, such as a calcium channel blocker or thiazide diuretic, that has a demonstrated benefit and a complementary way of working. Most people require two drugs from different pharmacologic classes to achieve their BP goal.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
4. Tips
- May be taken with or without food.
- Usually administered once daily; however, can be administered twice daily if benazepril's blood pressure-lowering capabilities start to wear off too early.
- Treatments that lower blood pressure, such as benazepril, should always be part of a comprehensive cardiovascular risk reduction plan that also targets, if appropriate, cholesterol-lowering, diabetes risk reduction, exercise, weight loss, and smoking cessation.
- Report a sore throat or any signs or symptoms of angioedema (swelling of the face or throat, difficulty breathing) immediately to your doctor.
- Your doctor may require you to undergo regular monitoring (such as kidney and liver tests) while taking benazepril.
- May cause a fall in blood pressure that may be noticed as light-headedness; this usually goes away after a few days of therapy. However, if it persists, call your doctor and ask for advice; symptoms usually resolve with continued therapy. Ensure you do not become dehydrated.
- Do not use salt substitutes or supplements containing potassium without first consulting your doctor.
- Report any signs of a fever or a sore throat to your doctor who may carry out further tests to ensure it is not neutropenia (a decrease in white blood cells).
- Ensure you use adequate contraception or are abstaining from sex to avoid pregnancy while taking benazepril. If you inadvertently become pregnant while taking benazepril, contact your healthcare provider immediately.
5. Response and effectiveness
- Peak concentrations of benazepril are reached within half an hour to one hour of oral administration. Benazepril is metabolized to an active metabolite, benazeprilat, which also lowers blood pressure.
- Blood pressure-lowering effects are seen within an hour of oral administration with peak effects achieved between two and four hours after dosing. Blood pressure-lowering effects are maintained for at least 24 hours, although in some patients these effects may diminish towards the end of the 24 hours. It may take several weeks before optimal blood pressure-lowering effects are achieved.
- Abrupt withdrawal of benazepril has not resulted in an abrupt increase in blood pressure; however, as with most antihypertensive drugs, it is best to discontinue benazepril slowly.
6. Interactions
Medicines that interact with benazepril may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with benazepril. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Common medications that may interact with benazepril include:
- aliskiren
- allopurinol (may enhance the potential for allergic reactions)
- amifostine
- amphetamines
- antipsychotic agents (may enhance the blood pressure-lowering effect)
- aspirin
- azathioprine
- diuretics, such as furosemide or hydrochlothiazide
- duloxetine
- ferric gluconate
- gold injections for arthritis (sodium aurothiomalate)
- grass pollen allergen extract
- heparin
- levodopa
- lithium
- mTOR inhibitors (such as everolimus, sirolimus, or temsirolimus)
- NSAIDs, such as ibuprofen, diclofenac, and naproxen (may result in deterioration of renal function; the effects are usually reversible)
- other ACE inhibitors (such as captopril or lisinopril) or ARBs (such as candesartan or irbesartan)
- other antihypertensives, such as calcium channel blockers, beta-blockers, or vasodilators (may cause an additive blood pressure-lowering effect)
- phosphodiesterase-5-inhibitors, such as sildenafil
- potassium supplements or potassium-sparing diuretics (such as amiloride or spironolactone)
- sacubitril
- trimethoprim.
Benazepril may also cause blood sugar levels to drop more than expected when taken with diabetes medication, including insulin. Increased blood sugar monitoring may be required.
Note that this list is not all-inclusive and includes only common medications that may interact with benazepril. You should refer to the prescribing information for benazepril for a complete list of interactions.