ACE Inhibitors: What They Do and How to Use Them Safely

ACE inhibitors are a common class of blood pressure medicines. Doctors prescribe them for high blood pressure, heart failure, after a heart attack, and to protect kidneys when protein shows up in urine. You’ll see drug names like lisinopril, enalapril, ramipril, captopril, and perindopril. Many are available as generics, which helps keep costs down.

How they work is simple: ACE inhibitors block the angiotensin-converting enzyme so your blood vessels relax and blood pressure falls. Less angiotensin II also lowers aldosterone, which can reduce fluid buildup in heart failure. The result is lower blood pressure and less strain on the heart and kidneys.

Common side effects and risks

The most talked-about side effect is a dry, persistent cough. About 5–20% of people who take ACE inhibitors get it; it often goes away when the drug stops. A rarer but serious problem is angioedema—swelling of lips, tongue, or throat—which needs emergency care. ACE inhibitors can also raise potassium levels and affect kidney function, so doctors check blood tests after starting treatment.

Never take ACE inhibitors during pregnancy — they can harm a developing baby. If you start feeling dizzy or faint, especially after the first dose, tell your provider. That first-dose drop in blood pressure is more likely if you’re on diuretics or dehydrated.

Practical tips: what to tell your doctor and when to check labs

Before you start, mention if you use NSAIDs, potassium supplements, or medications like spironolactone or potassium-sparing diuretics. Those can increase the risk of high potassium or kidney problems. Expect a baseline blood test for creatinine and potassium, and another test within 1–2 weeks after starting or changing dose. Blood pressure checks are also important.

Buying ACE inhibitors online? Make sure the pharmacy asks for a prescription and shows credentials like CIPA or NABP approvals. Cheap pills can be real but sometimes unsafe — read reviews and verify contact details. If you’re switching brands or buying generics, confirm the active ingredient and dose with your pharmacist.

If side effects become bothersome, don’t stop suddenly. Talk to your doctor about switching to an angiotensin receptor blocker (ARB) or adjusting the dose. ARBs often work similarly but are less likely to cause cough. Keep a list of all medicines you take and carry it to appointments.

Typical starting doses vary: for lisinopril adults often start at 10 mg once daily, enalapril 5 mg twice daily, and captopril doses are smaller and split through the day. Older adults or people on diuretics may start lower. If you miss a dose, take it when you remember unless it’s near the next dose—don’t double up. Store tablets at room temperature away from moisture. If your creatinine rises after starting, your doctor may reduce the dose or stop the drug.

Questions about interactions, dosing, or safety? Ask your prescriber or pharmacist. ACE inhibitors are effective for many people, but safe use depends on basic checks and good communication with your healthcare team.