Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CARDIZEM 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 inhibits calcium influx into cardiac and vascular smooth muscle cells during depolarization by binding to L-type calcium channels. This results in coronary vasodilation, decreased myocardial oxygen demand, and negative chronotropic and inotropic effects.
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.
Angina pectoris (chronic stable, vasospastic),Atrial fibrillation or atrial flutter (rate control),Hypertension
Hypertension,Chronic stable angina,Vasospastic angina (Prinzmetal's angina)
Oral: 30-120 mg three to four times daily; extended-release: 120-360 mg once daily. IV: Initial 0.25 mg/kg (max 25 mg) bolus over 2 minutes, may repeat in 15 minutes (0.35 mg/kg); maintenance: 5-15 mg/hour continuous infusion.
30-60 mg orally once daily, extended-release; maximum 90 mg/day.
Terminal elimination half-life is 3.0-4.5 hours in healthy adults; may be prolonged to 7-9 hours in elderly, hepatic impairment, or renal impairment; clinically relevant for dosing frequency.
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; metabolites: desacetyl diltiazem (active, 40-50% potency), N-demethylated, and deacetylated forms.
Primarily hepatic via CYP3A4; undergoes extensive first-pass metabolism.
Primarily hepatic metabolism with extensive first-pass effect; approximately 2-4% excreted unchanged in urine; fecal excretion accounts for about 65% of dose as metabolites; renal excretion accounts for about 35% of dose as metabolites.
Renal (80% as inactive metabolites), fecal (15% as metabolites), unchanged drug (<1%)
77-87% bound to plasma proteins, primarily albumin.
92-98% bound to plasma proteins (primarily albumin)
3-5 L/kg; large Vd indicates extensive tissue binding and distribution.
0.5-0.9 L/kg; high distribution indicates extensive tissue binding
Oral: 40-50% due to significant first-pass metabolism (range 30-60% across individuals); IV: 100%.
Oral extended-release: approximately 50-60% due to first-pass metabolism; absolute bioavailability is 45-60%
No specific dose adjustment for renal impairment; use with caution in severe renal dysfunction (Cr Cl <30 m L/min) with close monitoring of heart rate and blood pressure.
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 Class A: No adjustment. Class B: Reduce total daily dose by 25-50%. Class C: Avoid use; if necessary, consider further dose reduction with careful monitoring.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated.
Oral: 1.5-2 mg/kg/day divided every 6-8 hours, maximum 3.5 mg/kg/day. Extended-release not recommended in children. IV: Use only with caution; dosing not well established; typical initial bolus 0.1-0.3 mg/kg over 2 minutes, maximum 10 mg; infusion 0.5-5 mcg/kg/min.
Not recommended for use in pediatric patients; safety and efficacy not established.
Start at lower end of dosing range: oral immediate-release 30 mg three times daily; extended-release 120 mg once daily. Increase slowly. IV: Lower initial bolus (0.15-0.2 mg/kg) and infusion rates (2-5 mg/hour). Monitor for hypotension and bradycardia.
Initiate at lower end of dosing range (30 mg once daily) due to increased sensitivity to hypotensive effects and potential for reduced hepatic clearance.
There is no FDA black box warning for CARDIZEM (diltiazem).
No FDA black box warning.
Symptomatic hypotension,Bradycardia or heart block (especially in sick sinus syndrome or AV block without pacemaker),Worsening heart failure in patients with reduced ventricular function,Hepatic injury (rare but elevated liver enzymes reported),Concomitant use with beta-blockers may increase risk of bradycardia and heart failure,Digitalis toxicity risk increased when used with digoxin,May exacerbate myasthenia gravis,Acute generalized exanthematous pustulosis (AGEP) and other severe cutaneous reactions,Gradual withdrawal recommended for chronic therapy to avoid angina exacerbation,May lower blood pressure, use with caution in patients with hypotension,Use in renal impairment: monitor carefully
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
Hypersensitivity to diltiazem or any component,Sick sinus syndrome (except with functioning ventricular pacemaker),Second- or third-degree AV block (except with functioning pacemaker),Severe hypotension (systolic < 90 mm Hg),Acute myocardial infarction with pulmonary congestion,Atrial fibrillation or flutter associated with accessory bypass tract (e.g., WPW syndrome; risk of ventricular tachycardia or fibrillation),Cardiogenic shock,Concurrent use with ivabradine,Lactation (due to potential adverse effects in infants)
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 as they inhibit CYP3A4 and can increase diltiazem levels, leading to toxicity. High-fat meals may increase absorption of some extended-release formulations; take with consistent meals. Alcohol may increase the risk of hypotension and dizziness. Maintain adequate hydration and avoid excessive salt intake to control blood pressure.
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.
No adequate studies in pregnant women. In animal studies, diltiazem (Cardizem) has been shown to cause skeletal abnormalities and increased fetal mortality at doses 5-10 times the maximum recommended human dose. Based on animal data and human experience with calcium channel blockers, risk cannot be ruled out. Use only if potential benefit justifies risk to fetus. 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 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 human milk. A study reported a milk-to-plasma (M/P) ratio of approximately 0.9. The estimated infant dose is 1-2% of maternal weight-adjusted dose. Caution is advised; consider waiting 3-4 hours after dose before breastfeeding to minimize exposure.
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.
Increased plasma volume and altered protein binding in pregnancy may reduce diltiazem concentrations; consider dose titration based on clinical response. No specific dose adjustment established; monitor therapeutic effect.
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.
Cardizem (diltiazem) is a non-dihydropyridine calcium channel blocker used for hypertension, angina, and atrial fibrillation/atrial flutter. It is contraindicated with IV beta-blockers due to risk of bradycardia and heart block. In AF, use IV form for rate control but avoid in WPW due to risk of ventricular pre-excitation. Diltiazem is metabolized by CYP3A4; caution with strong inhibitors like clarithromycin or grapefruit juice. For hypertension, start at 30 mg TID or extended-release once daily. Monitor heart rate and PR interval; avoid in sick sinus syndrome or second/third-degree AV block without pacemaker.
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 this medication exactly as prescribed; do not crush or chew extended-release capsules.,Avoid grapefruit and grapefruit juice while taking this medication.,If you miss a dose, take it as soon as you remember unless it is almost time for your next dose; do not double the dose.,Do not stop taking this medication abruptly, as it may worsen your condition.,Common side effects include dizziness, headache, and swelling in the ankles/feet; contact your doctor if you experience slow heartbeat, shortness of breath, or fainting.,This medication may cause dizziness or lightheadedness; avoid driving or operating machinery until you know how it affects you.
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 CARDIZEM vs AFEDITAB CR, answered by our medical review team.
CARDIZEM is a Calcium Channel Blocker that works by Diltiazem inhibits calcium influx into cardiac and vascular smooth muscle cells during depolarization by binding to L-type calcium channels. This results in coronary vasodilation, decreased myocardial oxygen demand, and negative chronotropic and inotropic effects.. 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 CARDIZEM 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 CARDIZEM is: Oral: 30-120 mg three to four times daily; extended-release: 120-360 mg once daily. IV: Initial 0.25 mg/kg (max 25 mg) bolus over 2 minutes, may repeat in 15 minutes (0.35 mg/kg); maintenance: 5-15 mg/hour continuous infusion.. 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 CARDIZEM 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. CARDIZEM is classified as Category C. No adequate studies in pregnant women. In animal studies, diltiazem (Cardizem) has been shown to cause skeletal abnormalities and increased fetal mortality at doses 5-10 times the . 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.