ACE Inhibitors — What Five FDA Labels Say About America’s Most Prescribed Blood Pressure Drug Class

The Package Insert series

The most prescribed blood pressure medication in the United States carries a boxed warning — the FDA’s most serious category — stating that it “can cause injury and death to the developing fetus.” That drug is lisinopril. The warning appears on every ACE inhibitor label. It is not new. It is not hidden. It has been there for decades. Most patients taking these drugs have never read it.

The labels contain more. ACE inhibitors can trigger angioedema — sudden swelling of the face, tongue, or airway — at a higher rate in Black patients. All five labels acknowledge the drugs work less effectively in Black patients when used alone. One drug in the class — quinapril — has never been evaluated for its effect on long-term mortality in heart failure. Every label states that whether the mechanism of action involves bradykinin “remains to be elucidated” — after 35 to 40 years on the market, they still do not fully know how it works. These are statements from the FDA-approved label, written by the manufacturers, reviewed by the regulators, and filed with the agency.

This installment of The Package Insert covers five ACE inhibitors: lisinopril (Zestril), enalapril (Vasotec), ramipril (Altace), benazepril (Lotensin), and quinapril (Accupril). Together they represent the top five most prescribed drugs in this class by US volume. Their initial FDA approvals span from 1985 (enalapril) to 1991 (ramipril and benazepril), giving the oldest of them four decades on the market. Everything below comes from the prescribing information filed with the FDA.

The Package Insert is a paid subscriber series. Each installment takes the FDA-approved labels for a major drug class, reads them front to back, and reports what they actually say — in the manufacturers’ own language, reviewed by the regulators, available to anyone who asks for them. If you’re currently taking an ACE inhibitor, considering one, or have a family member on one, this is the installment to start with.

What paid subscribers will find below:

• What the labels say the drugs actually do — which have mortality data and which only lower a number

• The swelling that can kill you — angioedema rates by race, including the abdominal form that mimics emergencies

• A class that still can’t explain itself — why every label says the mechanism “remains to be elucidated”

• The cough they didn’t recognize — how early trials missed a side effect in up to 12% of patients

• What the labels say about your brain — mood alterations, hallucinations, amnesia, and depression

• Fetal toxicity and the kidney damage window — irreversible renal toxicity at specific developmental stages

• The tumor findings in one drug — hemangiomas and lipomas in female rats on quinapril

• NSAIDs and the interaction most patients don’t know about — what ibuprofen does to kidney function on an ACE inhibitor

• What the labels admit has never been studied — the accumulated gaps across four decades

• 12 questions to take to your doctor — specific, label-sourced, printable

Other drugs in the series

Statins — Five Labels, One Drug Class