Nifedipine
Brand names: Procardia, Adalat
Class: 🩺 Calcium Channel Blockers
The NP-board angle on nifedipine is recognizing two distinct uses — extended-release for hypertension and immediate-release for tocolysis in preterm labor. As a dihydropyridine calcium channel blocker, nifedipine vasodilates without slowing the heart, treating chronic stable angina, vasospastic (Prinzmetal) angina, and hypertension when used as the ER formulation. Immediate-release nifedipine is dangerous for routine BP control (reflex tachycardia, ischemia) but is a standard tocolytic agent for preterm labor between 24 and 34 weeks. It is also acceptable for hypertension in pregnancy (ER), alongside labetalol and methyldopa. Peripheral edema, headache, and flushing are the dose-dependent side effects; avoid grapefruit juice (CYP3A4).
✅ Indications
HTN (ER), chronic stable/vasospastic angina, TOCOLYSIS in preterm labor.
⚙️ Mechanism of Action
Dihydropyridine CCB.
📏 Dosing
ER: 30–90 mg daily. IR form avoided for HTN (reflex tachycardia/hypotension).
🚫 Contraindications
Severe aortic stenosis, within 1 month of MI (IR form), cardiogenic shock.
⚠️ Adverse Effects
Peripheral edema, flushing, headache, gingival hyperplasia, reflex tachycardia.
🔬 Monitoring
BP, HR.
💎 Board Pearls
- 🤰 TOCOLYTIC: delays preterm labor 24–48 hours to allow steroid course for fetal lung maturity.
- ⚠️ Immediate-release nifedipine NOT for chronic HTN — causes dangerous reflex hypotension/tachycardia.
Related Drugs in This Class
- Amlodipine — Norvasc
- Diltiazem — Cardizem, Tiazac
- Verapamil — Calan, Verelan
Sources
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