Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DILTZAC vs AFEDITAB CR
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Diltiazem is a calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cells, resulting in dilation of coronary and systemic arteries and decreased myocardial contractility and conduction velocity.
Nifedipine is a dihydropyridine calcium channel blocker that inhibits the influx of calcium ions through L-type channels in vascular smooth muscle and cardiac muscle, leading to vasodilation and reduced myocardial contractility.
Hypertension,Chronic stable angina,Atrial fibrillation or flutter,Paroxysmal supraventricular tachycardia,Off-label: Prevention of migraine, Raynaud's phenomenon
Hypertension,Chronic stable angina,Vasospastic angina (Prinzmetal's angina)
Oral: 30-120 mg 3-4 times daily; maximum 480 mg/day. IV: 0.25 mg/kg over 2 min, then 0.35 mg/kg after 15 min if needed; continuous infusion 5-15 mg/hour.
30-60 mg orally once daily, extended-release; maximum 90 mg/day.
Terminal elimination half-life: 3.5-5.0 hours (healthy adults). Prolonged in elderly (6-8 hours) and in hepatic impairment (10-12 hours).
Terminal elimination half-life is 6-11 hours; prolonged in hepatic impairment and elderly due to reduced clearance
Hepatic via CYP3A4; undergoes extensive first-pass metabolism
Primarily hepatic via CYP3A4; undergoes extensive first-pass metabolism.
Renal: 60-70% as metabolites, 2-4% unchanged; Biliary/Fecal: 20-30% as metabolites.
Renal (80% as inactive metabolites), fecal (15% as metabolites), unchanged drug (<1%)
80-85% bound to plasma proteins (albumin and alpha-1-acid glycoprotein).
92-98% bound to plasma proteins (primarily albumin)
5-6 L/kg (suggests extensive tissue distribution).
0.5-0.9 L/kg; high distribution indicates extensive tissue binding
Oral immediate-release: 40-60% (due to extensive first-pass hepatic metabolism). Extended-release: 30-40%. Intravenous: 100%.
Oral extended-release: approximately 50-60% due to first-pass metabolism; absolute bioavailability is 45-60%
No adjustment required for GFR >30 m L/min. For GFR 10-30 m L/min, reduce dose by 25%. For GFR <10 m L/min, reduce dose by 50%.
No adjustment required for any degree of renal impairment, but use with caution in patients with severe renal failure due to risk of hypotension.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: reduce dose by 75%.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated.
Oral: 1-3 mg/kg/day divided 3-4 times; maximum 3 mg/kg/day. IV: 0.25 mg/kg over 2 min; may repeat 0.35 mg/kg after 15 min; infusion 5-15 mcg/kg/min.
Not recommended for use in pediatric patients; safety and efficacy not established.
Start at lowest dose (30 mg 3-4 times daily) due to increased bioavailability and reduced clearance; titrate slowly. IV dose: 0.2 mg/kg over 2 min.
Initiate at lower end of dosing range (30 mg once daily) due to increased sensitivity to hypotensive effects and potential for reduced hepatic clearance.
None.
No FDA black box warning.
May cause heart block, bradycardia, exacerbation of heart failure, hypotension, and hepatotoxicity. Monitor liver function, ECG, and blood pressure. Avoid abrupt discontinuation; taper gradually.
Hypotension, especially with immediate-release formulations,Peripheral edema,Hepatic impairment,Increased angina/acute MI upon withdrawal or dose escalation,Beta-blocker withdrawal,Congestive heart failure
Sick sinus syndrome (except with pacemaker), second- or third-degree AV block (except with pacemaker), hypotension (systolic <90 mm Hg), cardiogenic shock, acute myocardial infarction with pulmonary congestion, hypersensitivity to diltiazem, concomitant use of ivabradine, and concurrent use with strong CYP3A4 inhibitors when diltiazem is given intravenously.
Hypersensitivity to nifedipine or any component,Cardiogenic shock,Concomitant use with strong CYP3A4 inducers (e.g., rifampin),Kock pouch (ileostomy)
Avoid grapefruit and grapefruit juice; they may increase diltiazem levels and risk of side effects. Alcohol may enhance blood pressure-lowering effects and cause dizziness. A high-fat meal may increase absorption, but this is not clinically significant.
Grapefruit juice increases nifedipine levels via CYP3A4 inhibition; avoid consumption. High-fat meals may delay absorption but do not alter overall exposure. Avoid alcohol as it can exacerbate vasodilation and hypotension.
First trimester: No definitive evidence of teratogenicity in animal studies; human data limited. Second and third trimesters: Chronic use may cause fetal bradycardia, hypoxia, and growth restriction due to maternal hypotension and reduced placental perfusion.
Teratogenic effects not established; first trimester: no data in humans, animal studies show no teratogenicity; second and third trimesters: risk of fetal hypoxia, intrauterine growth restriction (IUGR), and oligohydramnios; may cause neonatal hypotension, bradycardia, and hypoglycemia if used near term. Contraindicated in pregnancy for hypertension; use only if benefit outweighs risk (e.g., tocolysis).
Diltiazem is excreted in breast milk with low levels. Milk-to-plasma ratio is approximately 0.28. Caution advised; monitor infant for bradycardia and hypotension.
Nifedipine excreted into breast milk; M/P ratio approximately 0.42-0.77; limited human data; no adverse effects reported in infants; use with caution during breastfeeding.
No standard dose adjustment required; however, increased plasma volume may reduce drug levels. Titrate to therapeutic effect with careful blood pressure monitoring.
Plasma clearance may increase due to higher volume of distribution and metabolism; no specific dose adjustment recommended; titrate based on maternal blood pressure and response; avoid around labor due to tocolytic effect.
Diltzac is a calcium channel blocker (diltiazem) used for hypertension, angina, and atrial fibrillation. Avoid in patients with sick sinus syndrome (without pacemaker), second/third-degree AV block, or severe hypotension. Use with caution in hepatic impairment and renal failure. Monitor heart rate and ECG for bradycardia. Adjust dose with CYP3A4 inhibitors (e.g., grapefruit) or inducers. Advise gradual withdrawal to avoid rebound hypertension.
AFEDITAB CR is a controlled-release formulation of nifedipine, a dihydropyridine calcium channel blocker. Avoid grapefruit juice as it inhibits CYP3A4 metabolism, increasing nifedipine levels. Use cautiously in patients with aortic stenosis or left ventricular dysfunction due to risk of hypotension. Do not crush or chew tablets; intact shell may appear in stool.
Take exactly as prescribed; do not stop abruptly or change dose without consulting your doctor.,Avoid grapefruit and grapefruit juice while taking Diltzac.,Do not drive or operate heavy machinery if you experience dizziness or lightheadedness.,Monitor for signs of heart failure (swelling of ankles, feet, or sudden weight gain) and report immediately.,Your doctor may need to do regular blood tests to check liver function and monitor your heart rate and blood pressure.
Swallow the tablet whole; do not crush, chew, or break it.,Avoid grapefruit juice while taking this medication.,Do not discontinue abruptly; taper under medical supervision.,Report symptoms of hypotension like dizziness or fainting.,Limit alcohol intake as it may worsen side effects.,Monitor for fluid retention (ankle swelling) and notify doctor if worsening.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about DILTZAC vs AFEDITAB CR, answered by our medical review team.
DILTZAC is a Calcium Channel Blocker that works by Diltiazem is a calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cells, resulting in dilation of coronary and systemic arteries and decreased myocardial contractility and conduction velocity.. AFEDITAB CR is a Calcium Channel Blocker that works by Nifedipine is a dihydropyridine calcium channel blocker that inhibits the influx of calcium ions through L-type channels in vascular smooth muscle and cardiac muscle, leading to vasodilation and reduced myocardial contractility.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DILTZAC and AFEDITAB CR depend on the specific clinical indication. These are both Calcium Channel Blocker agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of DILTZAC is: Oral: 30-120 mg 3-4 times daily; maximum 480 mg/day. IV: 0.25 mg/kg over 2 min, then 0.35 mg/kg after 15 min if needed; continuous infusion 5-15 mg/hour.. The standard adult dose of AFEDITAB CR is: 30-60 mg orally once daily, extended-release; maximum 90 mg/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between DILTZAC and AFEDITAB CR in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. DILTZAC is classified as Category C. First trimester: No definitive evidence of teratogenicity in animal studies; human data limited. Second and third trimesters: Chronic use may cause fetal bradycardia, hypoxia, and . AFEDITAB CR is classified as Category C. Teratogenic effects not established; first trimester: no data in humans, animal studies show no teratogenicity; second and third trimesters: risk of fetal hypoxia, intrauterine gro. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.