Nifedipine ER 30 mg is a blood pressure and heart medication used primarily to treat high blood pressure (hypertension) and chronic stable angina, a type of recurring chest pain caused by reduced blood flow to the heart. The “ER” stands for extended release, meaning the tablet slowly delivers the medication over a full 24 hours so you only need to take it once a day.
How Nifedipine ER Works
Nifedipine belongs to a class of drugs called calcium channel blockers. Your blood vessels contain smooth muscle cells that need calcium to contract and tighten. Nifedipine blocks calcium from entering those cells, which causes the blood vessels to relax and widen. This has two important effects: it lowers blood pressure by reducing resistance in your arteries, and it increases blood flow to the heart muscle, relieving chest pain in people with angina.
The extended-release tablet is specifically designed to raise drug levels in your blood gradually, reaching a plateau about six hours after you take it. From there, it maintains relatively steady levels for the rest of the 24-hour period with minimal ups and downs. This smooth delivery matters because older, immediate-release forms of nifedipine caused rapid drops in blood pressure that led to more side effects.
Primary Uses: Blood Pressure and Angina
For hypertension, nifedipine ER 30 mg is typically the starting dose. If your blood pressure isn’t controlled after one to two weeks, your prescriber may increase the dose. Titration usually happens over a 7 to 14 day period, and doses above 90 mg daily are not recommended.
For chronic stable angina, the medication works by relaxing the coronary arteries that supply your heart with blood. By widening these vessels, nifedipine allows more oxygen-rich blood to reach the heart muscle, which reduces the frequency and severity of chest pain episodes during physical activity or stress.
Off-Label Use for Raynaud’s Phenomenon
Beyond its official uses, nifedipine is one of the most commonly prescribed medications for Raynaud’s phenomenon, a condition where blood vessels in the fingers and toes spasm in response to cold or stress, turning them white or blue. Because nifedipine relaxes blood vessel walls, it can reduce the frequency, duration, and severity of these attacks, along with the pain and disability they cause. The UK’s National Institute for Health and Care Excellence (NICE) notes there is currently no good evidence recommending drugs other than calcium channel blockers for Raynaud’s. Higher doses tend to be more effective than lower ones, and the benefit is clearer for primary Raynaud’s (the kind without an underlying autoimmune disease) than for secondary forms.
Common Side Effects
The most frequently reported side effects are closely tied to the drug’s blood vessel-relaxing mechanism. In clinical trials of over 660 patients with hypertension, these were the most common:
- Swelling (peripheral edema): 10% or more at the 30 mg dose, increasing at higher doses up to about 30% at 120 mg. This usually shows up in the ankles and feet.
- Headache: roughly 12 to 17% of patients
- Fatigue: about 6%
- Dizziness: about 4%
- Constipation: about 3.5%
- Nausea: about 3.5%
- Flushing or feeling warm: about 2.5%
Swelling and flushing happen because the drug widens blood vessels, which can allow fluid to leak into surrounding tissues. Many of these side effects are more pronounced at higher doses, which is one reason prescribers start at 30 mg and increase gradually.
Important Precautions
People with tight aortic stenosis (a severely narrowed heart valve) face a higher risk of heart failure on nifedipine, because the blood pressure-lowering effect can’t overcome the fixed obstruction at the valve. In rare cases, patients with severe coronary artery disease have experienced worsening chest pain or even heart attacks when starting nifedipine or increasing the dose.
The extended-release tablet uses a special shell that passes through your digestive tract intact after releasing the medication. Because of this design, people with significant gastrointestinal narrowing, prior bowel surgery, gastric bypass, or conditions that slow gut movement may be at risk for a blockage. If you’ve had any of these, your prescriber needs to know before starting this medication.
Grapefruit Juice Interaction
Nifedipine is one of the well-known medications that interacts with grapefruit juice. Your small intestine uses an enzyme to break down nifedipine before it enters your bloodstream. Grapefruit juice blocks that enzyme, so more of the drug gets absorbed and stays in your body longer than intended. The result is an amplified effect, which can cause your blood pressure to drop too low. Avoiding grapefruit and grapefruit juice while taking nifedipine ER is the simplest way to prevent this.
How to Take It
Take the tablet once daily on an empty stomach, either one hour before or two hours after a meal, at the same time each day. Swallow it whole. Do not split, crush, or chew it, as doing so would release the full dose at once instead of gradually over 24 hours.
If you miss a dose, take it as soon as you remember. If it’s close to the time for your next dose, skip the missed one and continue your regular schedule. Do not double up to compensate for a missed dose.
You may notice the empty tablet shell in your stool. This is normal and does not mean the medication wasn’t absorbed. The drug has already been released inside your body; the outer shell simply passes through.