The Simple Answer: What is the generic name of nifedipine?
When discussing pharmaceuticals, the distinction between generic and brand-name drugs is crucial. For the medication nifedipine, the answer to the question is simple: nifedipine is the generic name [1.2.4]. It is marketed under several brand names, including Procardia, Procardia XL, Adalat, and Adalat CC [1.2.1]. This medication belongs to a class of drugs known as calcium channel blockers, specifically the dihydropyridine subclass, and was first granted FDA approval on December 31, 1981 [1.2.5, 1.4.2].
Understanding Nifedipine's Mechanism of Action
Nifedipine functions as a calcium ion influx inhibitor, which means it blocks the passage of calcium ions into cardiac muscle and smooth muscle cells [1.3.3]. The contraction of these muscles depends on the movement of extracellular calcium into the cells through specific channels. By selectively inhibiting this calcium influx, nifedipine causes blood vessels to relax and widen (vasodilation) [1.3.5]. This relaxation makes it easier for the heart to pump blood, which in turn lowers blood pressure and increases the supply of blood and oxygen to the heart muscle [1.3.5, 1.3.6]. It accomplishes this without changing the concentration of calcium in the blood serum [1.3.3].
What is Nifedipine Prescribed For?
The FDA has approved nifedipine for treating several cardiovascular conditions [1.4.2]. Its primary uses are:
- Hypertension (High Blood Pressure): The extended-release formulations of nifedipine are used as a first-line treatment for managing high blood pressure, either as a standalone therapy or in combination with other medications [1.4.3, 1.4.1].
- Chronic Stable Angina: This refers to chest pain that occurs with physical activity or emotional stress. Nifedipine helps by reducing the heart's oxygen demand [1.3.6].
- Vasospastic Angina (Prinzmetal's or Variant Angina): This type of angina is caused by spasms in the coronary arteries. Nifedipine is a potent inhibitor of these spasms, which helps increase oxygen delivery to the heart [1.3.6, 1.4.3].
Off-Label Applications
Beyond its approved uses, healthcare providers also prescribe nifedipine for several off-label conditions:
- Raynaud's Phenomenon: A condition where blood flow to fingers and toes is restricted in response to cold or stress [1.4.1, 1.4.4].
- Hypertension During Pregnancy: The American College of Obstetricians and Gynecologists (ACOG) recommends extended-release nifedipine as a first-choice agent for managing high blood pressure during pregnancy [1.4.3, 1.4.1].
- Pulmonary Arterial Hypertension (PAH): High blood pressure in the arteries of the lungs [1.4.1].
- Preterm Labor (Tocolysis): It can be used short-term to inhibit uterine contractions [1.4.5].
Comparison: Immediate-Release vs. Extended-Release Nifedipine
Nifedipine is available in two main forms: immediate-release (IR) and extended-release (ER). The choice between them is critical and depends on the condition being treated [1.5.1]. The immediate-release version, often found in capsules, has a rapid onset of action but also a short half-life, requiring multiple doses per day [1.5.1, 1.8.1]. This can cause rapid drops in blood pressure and reflex sympathetic activation, leading to side effects like headaches and palpitations [1.5.1]. Due to these risks, the 2023 American Geriatric Society Beers Criteria recommends avoiding the IR formulation in older adults [1.6.2].
The extended-release tablets (like Procardia XL and Adalat CC) are designed to release the medication slowly over 24 hours, providing more stable blood pressure control with fewer side effects [1.5.1, 1.3.6].
| Feature | Immediate-Release (IR) Nifedipine | Extended-Release (ER) Nifedipine |
|---|---|---|
| Formulation | Capsules (e.g., Procardia) [1.2.6] | Tablets (e.g., Procardia XL, Adalat CC) [1.2.6] |
| Dosing Frequency | Typically 3-4 times per day [1.8.1] | Once daily [1.8.1] |
| Onset of Action | Rapid (within 20 minutes) [1.5.1] | Gradual, reaching a plateau around 6 hours [1.5.1] |
| Primary Use | Angina [1.8.1] | Hypertension and Angina [1.4.1] |
| Side Effect Profile | Higher risk of rapid blood pressure drops, palpitations, and headache [1.5.1] | Smoother blood pressure control, fewer adverse effects [1.5.1] |
Common and Serious Side Effects
Like all medications, nifedipine can cause side effects.
Common side effects include:
- Headache [1.6.1]
- Flushing (feeling of warmth) [1.6.1]
- Dizziness or lightheadedness [1.6.1]
- Swelling of the ankles, feet, or legs (edema) [1.6.5]
- Heartburn and nausea [1.6.1]
- Muscle cramps [1.6.3]
- Constipation [1.6.1]
Serious side effects that require immediate medical attention:
- Worsening chest pain (angina) [1.6.1]
- Difficulty breathing or swallowing [1.6.1]
- Symptoms of a heart attack (pain in chest, shoulders, or jaw) [1.4.6]
- Signs of heart failure (sudden weight gain, unusual fatigue, swelling) [1.4.6]
- Fainting (syncope) [1.6.1]
- Severe skin rash or allergic reactions [1.6.1]
Important Warnings and Drug Interactions
Patients should not take nifedipine if they are in cardiogenic shock [1.6.2]. It should be used with caution in individuals with severe aortic stenosis, heart failure, or severe liver impairment [1.6.2]. A critical warning involves grapefruit and grapefruit juice, which must be avoided while taking nifedipine. Grapefruit inhibits an enzyme (CYP3A4) that metabolizes the drug, leading to significantly higher levels of nifedipine in the blood and increasing the risk of side effects like low blood pressure and dizziness [1.9.1, 1.9.2, 1.7.2]. Nifedipine can also interact with many other drugs, including certain antibiotics, antifungals, other blood pressure medications, and St. John's wort [1.7.5, 1.4.6]. Always inform your doctor of all medications and supplements you are taking.
Conclusion
In summary, nifedipine itself is the generic name for a vital calcium channel blocker used to manage high blood pressure and angina. It is available under brand names like Procardia and Adalat CC and comes in both immediate-release and extended-release formulations, with the latter being preferred for its safety and stability. While effective, it carries a risk of side effects and significant drug interactions, most notably with grapefruit juice. As with any prescription medication, it should only be used under the guidance of a healthcare professional who can determine the appropriate form and dosage for your specific needs.
