Is nifedipine short‑acting or long‑acting?

Nifedipine Formulation: Short-Acting vs Long-Acting

Nifedipine exists in both short-acting (immediate-release) and long-acting (extended-release) formulations, and the distinction is critical because immediate-release nifedipine carries significant safety risks and should be avoided for routine hypertension or angina management unless administered with concomitant beta-blockade. 1

Formulation Characteristics

Immediate-Release (Short-Acting) Nifedipine

• Duration of action is 4-6 hours, requiring multiple daily doses (typically 3 times daily at 30-90 mg total daily dose) 1, 2
• Onset of action is rapid: 10-15 minutes when given buccally, 30-45 minutes when given orally 2
• Peak effect occurs at 30 minutes (buccal) or 60 minutes (oral) 2
• The immediate-release formulation is classified as "short" duration in the American Heart Association/American College of Cardiology guidelines 1

Extended-Release (Long-Acting) Nifedipine

• Duration of action is approximately 24 hours, permitting once-daily dosing at 30-180 mg daily 1, 3
• Plasma concentrations reach a plateau within 6 hours and maintain relatively constant levels for at least 24 hours 4
• The extended-release formulation is classified as "long" duration in major cardiovascular guidelines 1
• The gastrointestinal therapeutic system (GITS) formulation uses an osmotic pump mechanism to provide approximately zero-order drug delivery, preventing dose dumping and maintaining smooth blood pressure control 4

Critical Safety Distinctions

Why Immediate-Release Should Be Avoided

• The American College of Cardiology explicitly states that rapid-release, short-acting dihydropyridines such as nifedipine must be avoided in the absence of concomitant beta blockade because of increased adverse potential 1
• Immediate-release nifedipine is not recommended for unstable angina/NSTEMI except with concomitant beta-blockade due to risks of precipitous blood pressure drops, myocardial infarction, and reflex tachycardia 1, 3
• Sublingual or rapid intravenous administration can cause precipitous blood pressure reduction leading to myocardial infarction or fetal distress in pregnancy 3

Preferred Clinical Use

• Extended-release nifedipine is the preferred formulation for chronic management of hypertension and angina because it provides more consistent plasma concentrations, better tolerability, and improved patient compliance with once-daily dosing 3, 5
• Immediate-release nifedipine should be reserved exclusively for acute severe hypertension (≥160/110 mmHg) in specific clinical contexts, never for maintenance therapy 3, 6

Pharmacokinetic Differences

• Extended-release formulations produce less fluctuation in plasma drug concentrations compared to immediate-release given three times daily, which may improve efficacy and tolerability 4
• The mean peak plasma concentration following a 90 mg extended-release tablet under fasting conditions is approximately 115 ng/mL 7
• When extended-release nifedipine is given after a high-fat meal, there is an average 60% increase in peak plasma concentration but no significant change in total drug exposure (AUC) 7

Clinical Algorithm for Formulation Selection

For chronic hypertension or stable angina:

• Use extended-release nifedipine 30-90 mg once daily 1, 3
• Maximum dose for angina is 180 mg daily 1, 3

For acute severe hypertension in pregnancy:

• Immediate-release nifedipine 10-20 mg orally (never sublingual) may be used 3, 6
• Can repeat every 20-30 minutes if blood pressure remains severely elevated, maximum 30 mg in first hour 6
• Must never combine with intravenous magnesium sulfate due to risk of precipitous hypotension 3, 6

Common pitfall to avoid:

• Do not use three 30 mg extended-release tablets to achieve a 90 mg dose, as this results in substantially higher peak concentrations (29% greater) than a single 90 mg tablet and should not be considered interchangeable 7