Nifedipine

Key facts

• Nifedipine (Adalat, Procardia) is a calcium channel blocker that relaxes blood vessel walls to lower blood pressure and ease chest pain.
• Extended-release tablets are taken once daily and must be swallowed whole; never crush, split, or chew them.
• Its single most important safety fact: immediate-release, fast-acting nifedipine must never be used to treat a hypertensive emergency or urgent, very high blood pressure. The rapid pressure drop this causes has been linked to stroke and heart attack.
• Seek urgent care for chest pain that worsens, fainting, or a very fast or irregular heartbeat.

What Nifedipine treats

Nifedipine treats high blood pressure and chronic stable or vasospastic angina, using the extended-release form for ongoing control of both. It is also used off-label for Raynaud's phenomenon and to relax the uterus during premature labor.

How Nifedipine works

Nifedipine blocks calcium from entering the muscle cells that line arteries. Without calcium influx, those muscle cells cannot contract as strongly, so the vessels widen, blood flows more easily, and the heart pumps against less resistance. The same relaxation of coronary arteries eases the spasm that causes angina.

Before you take it

• Avoid nifedipine if you have severe aortic stenosis or very low blood pressure.
• Tell your prescriber about heart failure, liver disease, or a recent heart attack, since your dose may need adjusting.
• Grapefruit juice raises nifedipine levels in your blood and can intensify its effects. Avoid it during treatment.
• Other blood-pressure medicines, some antifungal drugs, and certain antibiotics can change how much nifedipine is in your system.

Side effects

Common effects include headache, flushing, ankle swelling, dizziness, and a fast or pounding heartbeat.

Stop and seek urgent medical care for any of these:

• Chest pain that is new, worsening, or does not ease with rest.
• Fainting or a sudden drop in blood pressure.
• A very fast or irregular heartbeat.
• Facial, lip, or throat swelling, or difficulty breathing.

Safety essentials

• Never use immediate-release nifedipine capsules for a hypertensive emergency or crisis. Rapid, uncontrolled blood-pressure drops from this form have caused strokes and heart attacks, so extended-release tablets are used for ongoing treatment instead.
• Swallow extended-release tablets whole. Crushing or chewing them releases the full dose at once and can cause a dangerous blood-pressure drop.
• Avoid grapefruit and grapefruit juice, which can raise nifedipine levels unpredictably.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.