Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DILACOR XR 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 ion influx across cardiac and vascular smooth muscle cells, resulting in dilation of coronary and systemic arteries, decreased myocardial contractility, and reduced sinoatrial and atrioventricular 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.
Angina pectoris due to coronary artery spasm (Prinzmetal's variant angina),Chronic stable angina,Essential hypertension
Hypertension,Chronic stable angina,Vasospastic angina (Prinzmetal's angina)
180 to 240 mg orally once daily, administered on an empty stomach; maximum dose 480 mg once daily.
30-60 mg orally once daily, extended-release; maximum 90 mg/day.
Terminal half-life: 6-12 hours (prolonged in elderly, hepatic impairment, or with CYP3A4 inhibitors)
Terminal elimination half-life is 6-11 hours; prolonged in hepatic impairment and elderly due to reduced clearance
Extensively metabolized in the liver via CYP3A4; undergoes deacetylation and N-demethylation.
Primarily hepatic via CYP3A4; undergoes extensive first-pass metabolism.
Renal (70% as metabolites, 3-4% as unchanged drug); biliary/fecal (25-30%)
Renal (80% as inactive metabolites), fecal (15% as metabolites), unchanged drug (<1%)
98-99% bound to serum albumin and alpha-1-acid glycoprotein
92-98% bound to plasma proteins (primarily albumin)
1.1-1.8 L/kg (high Vd indicates extensive tissue binding)
0.5-0.9 L/kg; high distribution indicates extensive tissue binding
Oral: 40-50% (first-pass metabolism; food does not affect extent)
Oral extended-release: approximately 50-60% due to first-pass metabolism; absolute bioavailability is 45-60%
GFR 30-60 m L/min: initiate at 120 mg once daily, titrate cautiously; GFR <30 m L/min: not recommended due to risk of accumulation.
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: initiate at 120 mg once daily; Child-Pugh Class B or C: avoid use.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated.
Safety and effectiveness in pediatric patients have not been established; no dosing recommendations.
Not recommended for use in pediatric patients; safety and efficacy not established.
Start at low end of dosing range (120 mg once daily) due to increased systemic exposure and risk of hypotension; titrate slowly.
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 hypotension, bradycardia, and heart block; avoid in patients with sick sinus syndrome or second- or third-degree AV block without a pacemaker; caution in patients with congestive heart failure; may increase risk of digitalis toxicity; abrupt withdrawal may worsen angina.
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 in presence of functioning ventricular pacemaker), second- or third-degree AV block (except with pacemaker), hypotension (systolic < 90 mm Hg), acute myocardial infarction with pulmonary congestion, hypersensitivity to diltiazem, concurrent use of ivabradine.
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 plasma concentrations, leading to increased risk of adverse effects. Avoid high-fat meals as they may affect the absorption of the extended-release formulation.
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.
DILACOR XR (diltiazem) is a calcium channel blocker with limited human pregnancy data. In animal studies, at doses up to 5 times the maximum recommended human dose, no teratogenic effects were observed. However, embryofetal toxicity (increased fetal loss, growth retardation) occurred at maternally toxic doses. First trimester: No adequate human studies; risk cannot be excluded. Second and third trimesters: Use only if clearly needed; may cause maternal hypotension and reduced uteroplacental blood flow, potentially leading to fetal hypoxia and growth restriction. U. S. FDA Pregnancy 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 breast milk. The milk-to-plasma (M/P) ratio ranges from 0.7 to 0.9. Limited data suggest infant exposure is low (approximately 1% of maternal weight-adjusted dose). No adverse effects reported in breastfed infants. Caution advised; monitor infant for bradycardia, hypotension, and sedation. Alternative agents may be preferred.
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.
Plasma volume and renal clearance increase during pregnancy, potentially reducing diltiazem concentrations. However, specific pharmacokinetic studies are lacking. Clinical response and blood pressure should guide dosing. Start at the lowest effective dose and titrate based on maternal heart rate and blood pressure. Avoid sustained-release formulations if rapid titration needed; immediate-release may be used. Monitor for hypotension, which may worsen uteroplacental perfusion. No specific dose adjustment recommended in published guidelines; use caution and individualized dosing.
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.
DILACOR XR is a sustained-release formulation of diltiazem, a calcium channel blocker. Do not crush or chew the capsule; swallowing whole is essential for extended-release properties. Monitor heart rate and blood pressure regularly due to risk of bradycardia and hypotension. Use with caution in patients with reduced hepatic function as diltiazem undergoes extensive first-pass metabolism. Avoid concurrent use with strong CYP3A4 inhibitors (e.g., ketoconazole) as they can increase diltiazem levels. In patients with atrial fibrillation or flutter, it may be used for rate control but contraindicated in sick sinus syndrome or second/third-degree AV block without a 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.
Swallow DILACOR XR capsules whole; do not crush, chew, or break them.,Take this medication exactly as prescribed, usually once daily. Do not stop suddenly without consulting your doctor.,Avoid grapefruit and grapefruit juice as they can increase the effects and side effects of diltiazem.,Limit alcohol intake as it may increase the risk of dizziness or fainting.,Notify your doctor if you experience slow heartbeat, shortness of breath, swelling of ankles/feet, or severe dizziness.,Keep a record of your blood pressure and pulse at home and bring it to appointments.,Do not take other medications, including over-the-counter products or herbal supplements, without consulting your healthcare provider.
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 DILACOR XR vs AFEDITAB CR, answered by our medical review team.
DILACOR XR is a Calcium Channel Blocker that works by Diltiazem inhibits calcium ion influx across cardiac and vascular smooth muscle cells, resulting in dilation of coronary and systemic arteries, decreased myocardial contractility, and reduced sinoatrial and atrioventricular 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 DILACOR XR 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 DILACOR XR is: 180 to 240 mg orally once daily, administered on an empty stomach; maximum dose 480 mg once daily.. 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 DILACOR XR 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. DILACOR XR is classified as Category C. DILACOR XR (diltiazem) is a calcium channel blocker with limited human pregnancy data. In animal studies, at doses up to 5 times the maximum recommended human dose, no teratogenic . 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.