Nifedipine

A fast-acting dihydropyridine calcium channel blocker for hypertension and angina.

What is Nifedipine?

Nifedipine is a dihydropyridine calcium channel blocker used in the treatment of hypertension and angina pectoris.

It primarily acts on vascular smooth muscle to reduce blood pressure.

History & Background

Nifedipine was one of the earliest calcium channel blockers developed and played a major role in modern hypertension management.

Chemical Structure & Properties

• IUPAC name: Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate
• Molecular formula: C₁₇H₁₈N₂O₆
• Molar mass: 346.33 g/mol
• Functional groups: Dihydropyridine, nitro group, ester

Mechanism of Action

Nifedipine lowers blood pressure by:

• Blocking L-type calcium channels
• Relaxing vascular smooth muscle
• Reducing peripheral vascular resistance

Pharmacokinetics

• Absorption: Rapid oral absorption
• Peak plasma time: 30–60 minutes (immediate-release)
• Half-life: ~2 hours
• Metabolism: Liver (CYP3A4)
• Excretion: Urine

Medical Uses

• Hypertension
• Chronic stable angina
• Vasospastic angina
• Raynaud’s phenomenon

Dosage Guidelines

Immediate-release: 10–20 mg three times daily

Extended-release: 30–90 mg once daily

⚠️ Avoid sudden BP drop with immediate-release forms.

Side Effects

• Headache
• Flushing
• Dizziness
• Ankle edema

Warnings & Precautions

• Avoid sublingual use
• Use caution in heart failure
• Monitor blood pressure closely

Drug Interactions

• Grapefruit juice
• Strong CYP3A4 inhibitors
• Other antihypertensive agents

Frequently Asked Questions

Is nifedipine fast-acting? – Yes (IR form).

Does it cause ankle swelling? – Common.

Is it safe long-term? – Yes, ER preferred.

Does it affect heart rate? – Minimal direct effect.

⚠️ Educational content only. Not a substitute for professional medical advice.