Drug reference

Nifedipine

Dihydropyridine calcium channel blocker · Antihiccup agent

START

Check BP, HR. Immediate-release is NOT recommended for chronic hypertension or angina (increases mortality risk in ACS). Use extended-release only for chronic conditions.

TYPICAL MAX

120mg/day ER. Edema is dose-limiting and NOT responsive to diuretics (venous, not sodium-mediated).

STOP IF

SBP <90 mmHg, syncope, acute heart failure, severe peripheral edema, unstable angina.

WATCH

Reflex tachycardia may worsen angina—use beta-blocker co-therapy if needed. Edema is very common—distinguish from heart failure (no JVP elevation, no pulmonary congestion). Grapefruit juice increases levels. Do NOT crush/chew ER tablets.

CDSCO approvedSchedule HATC C08CA05

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1.5h · ER onset 1-2 hours
PEAK: 6h · Tmax ER ~6 hours
t½: 8h · t½ ER 6-10 hours
DURATION: 1d · 24 hours (ER)

EXCRETION

Renal as metabolites (~80%)

route + CYP

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Commonly used for pregnancy-related hypertension and preterm labor tocolysis. No teratogenic effects documented. Fetal safety well-established. Preferred CCB in pregnancy (with labetalol and methyldopa).

FDA category + note

Top interactionssee all 12 →

ApalutamideSevereDatabaseDDInter
CarbamazepineSevereDatabaseDDInter
CeritinibSevereDatabaseDDInter
CisaprideSevereDatabaseDDInter

Available in India

75 branded formulations and 9 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Mechanism

Selectively inhibits L-type voltage-gated calcium channels in vascular smooth muscle, causing arterial vasodilation (much greater effect on arteries than veins or myocardium). Reduces peripheral vascular resistance and blood pressure. Minimal direct effect on cardiac conduction or contractility at therapeutic doses.

Indications

Hypertension (extended-release formulations)Chronic stable anginaVasospastic (Prinzmetal's) anginaPreterm labor tocolysis (off-label in some countries; approved in others)Raynaud's phenomenon

Dosing

Adult: Hypertension (ER): 30mg PO daily initially, titrate every 7-14 days to 60-90mg daily (max 120mg). Angina (ER): 30-60mg daily. Immediate-release (not recommended for chronic use): 10mg PO TID, max 30mg QID. Preterm labor: 20mg PO loading, then 10-20mg Q6-8h.
Pediatric: Not established for hypertension in children.
Renal adjustment: No adjustment needed.
Hepatic adjustment: Reduce dose 50-70% in cirrhosis; monitor BP closely.
Geriatric: Start 30mg ER daily; increased sensitivity to hypotension; monitor for edema and dizziness.
Max dose: 120mg/day (ER); 180mg/day (IR)

Pharmacokinetics

Onset

IR: 10-30 minutes; ER: 1-2 hours

Peak effect

IR: Tmax 30-60 minutes; ER: Tmax 6 hours; antihypertensive steady-state in 3-5 days

Duration

IR: 4-6 hours; ER: 24 hours

Half-life

IR: 2-5 hours; ER: 6-10 hours (prolonged absorption)

Bioavailability

~45-75% (IR); ~85% (ER); extensive first-pass metabolism

Protein binding

~92-98%

Metabolism

Extensive hepatic via CYP3A4 to inactive metabolites

Excretion

~80% renal (metabolites); ~15% fecal

Contraindications

Hypersensitivity to nifedipine
Cardiogenic shock
Severe aortic stenosis
Unstable angina (immediate-release contraindicated—increases MI risk)
Concomitant rifampicin (strong CYP3A4 inducer)

Side effects

Common

Peripheral edema (dose-dependent, very common—venous pooling)HeadacheFlushingDizzinessTachycardia (reflex)Gingival hyperplasia (chronic use)Constipation

Serious