Nifedipine: what it treats, how to take it, side effects
Last updated September 3, 2026.
Nifedipine is a calcium channel blocker - it relaxes your blood vessels so your heart pumps against less resistance. You may know it as Procardia XL. It lowers blood pressure and controls angina, and it comes with a famous food rule: no grapefruit.
What does it treat?
High blood pressure and angina (chest pain). It relaxes blood vessels to lower pressure and increases blood and oxygen supply to the heart to control chest pain. One nuance: taken regularly, it controls chest pain but does not stop an attack once one starts - your doctor prescribes a separate medication for that moment.
How do you take it?
Two forms with different rhythms. The capsule is taken three or four times a day. The extended-release tablet is once a day on an empty stomach - 1 hour before or 2 hours after a meal - swallowed whole, never split, chewed, or crushed. Most people on long-term treatment are on the extended-release tablet, which comes in 30 mg, 60 mg, and 90 mg. Your doctor starts low and increases gradually, usually no more than once every 7 to 14 days. The grapefruit rule: MedlinePlus says do not drink grapefruit juice or eat grapefruit for 3 days before and while taking nifedipine. Never stop without your doctor - the exit is a gradual decrease. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: headache, nausea, dizziness or lightheadedness, flushing, heartburn, fast heartbeat, muscle cramps, constipation, cough, and decreased sexual ability.
- Serious - call your doctor immediately or get emergency care: swelling of the face, eyes, lips, tongue, hands, arms, feet, ankles, or lower legs; difficulty breathing or swallowing; and fainting.
Who should not take it?
If you are 65 or older, MedlinePlus says the capsules are usually not the right choice - they may be less safe than alternatives, a direct doctor conversation. Flag any narrowing or blockage of the digestive system or conditions that slow it, heart, liver, or kidney disease, and a heart attack within the last 2 weeks. St. John's wort and cimetidine interact. Alcohol makes the side effects worse - ask your doctor for the rule. If you become pregnant, call your doctor.
When is it an emergency?
Fainting, or trouble breathing or swallowing, is a 911 call. Facial or tongue swelling is the allergic-reaction version of the same call. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why can't I eat grapefruit with nifedipine?
It changes the dose your body sees. MedlinePlus states it as a hard rule: no grapefruit or grapefruit juice for 3 days before and while taking nifedipine. Grapefruit blocks the enzyme that clears the drug, so levels climb higher than prescribed. Other citrus is fine - grapefruit specifically is out, the whole course.
Why do I take the extended-release tablet on an empty stomach?
Food changes the release. MedlinePlus says the extended-release tablet should be taken once daily on an empty stomach, 1 hour before or 2 hours after a meal - and swallowed whole, never split, chewed, or crushed, because the shell is the timing mechanism. First-thing-in-the-morning, breakfast an hour later, is the routine most people land on.
Why does nifedipine make my face flush?
Relaxed vessels, visibly. The same vessel relaxation that lowers your pressure shows up as flushing, warmth, and headache - all on MedlinePlus's common list, worst in the first days and after dose increases. It usually settles as your body calibrates. Flushing with swelling of the face, lips, or tongue is a different event - that one is a call-immediately.
Why won't my nifedipine stop a chest pain attack once it starts?
It is a prevention drug, not a rescue drug. MedlinePlus explains: taken regularly, nifedipine controls chest pain, but it does not stop chest pain once it starts - your doctor prescribes a different medication for the attack itself. If your angina pattern changes or attacks come more often, that is a prompt doctor conversation.
Can I drink alcohol while taking nifedipine?
Ask your doctor - MedlinePlus says alcohol can make nifedipine's side effects worse. Both dilate blood vessels, so the dizziness and flushing stack. Whatever limit your doctor sets becomes part of the prescription.
What happens if I miss a dose of nifedipine?
Take it as soon as you remember, unless it is almost time for the next one - then skip it and never double up. With the once-daily tablet, anchor it to waking up and it becomes automatic. A pattern of misses shows up in your pressure log.