Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DILTZAC vs ADALAT
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.
Dihydropyridine calcium channel blocker; inhibits calcium ion influx across cardiac and vascular smooth muscle cells, reducing peripheral vascular resistance and blood pressure.
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.
10-20 mg orally three times daily; extended-release: 30-60 mg orally once daily; maximum 120 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: 2-5 hours (immediate-release); 8-14 hours (extended-release). Context: shorter half-life necessitates multiple daily dosing for immediate-release; extended-release allows once-daily dosing.
Hepatic via CYP3A4; undergoes extensive first-pass metabolism
Hepatic via CYP3A4; extensive first-pass metabolism; metabolites are inactive.
Renal: 60-70% as metabolites, 2-4% unchanged; Biliary/Fecal: 20-30% as metabolites.
Renal: 70-80% as metabolites; Fecal: 15-20% as metabolites; <1% unchanged in urine
80-85% bound to plasma proteins (albumin and alpha-1-acid glycoprotein).
92-98% bound to plasma proteins (albumin and alpha-1-acid glycoprotein)
5-6 L/kg (suggests extensive tissue distribution).
0.8-1.2 L/kg. Clinical meaning: indicates extensive tissue distribution, consistent with high lipophilicity.
Oral immediate-release: 40-60% (due to extensive first-pass hepatic metabolism). Extended-release: 30-40%. Intravenous: 100%.
Oral immediate-release: 45-60% (due to first-pass metabolism); extended-release: 60-85% (due to slower release and reduced first-pass effect).
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 dose adjustment required for GFR ≥30 m L/min; for GFR <30 m L/min, use with caution and reduce initial dose by 50%.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: reduce dose by 75%.
Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use or reduce by 75%.
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.
0.25-0.5 mg/kg/dose orally every 6-8 hours; maximum 3 mg/kg/day. Extended-release not recommended.
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.
Start at 10 mg orally twice daily; titrate slowly due to increased sensitivity and risk of hypotension.
None.
None
May cause heart block, bradycardia, exacerbation of heart failure, hypotension, and hepatotoxicity. Monitor liver function, ECG, and blood pressure. Avoid abrupt discontinuation; taper gradually.
May cause hypotension, especially in patients on beta-blockers or with poor cardiac reserve,Risk of increased angina and/or myocardial infarction upon initiation or dose increase,Peripheral edema,Stevens-Johnson syndrome and toxic epidermal necrolysis (rare),Hepatic impairment,Exacerbation of angina on withdrawal
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,Cardiogenic shock,Significant aortic stenosis,Concurrent use with rifampin,Pregnancy (category C)
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.
Avoid grapefruit and grapefruit juice; they inhibit CYP3A4 and increase nifedipine serum concentrations, leading to enhanced hypotensive effects and risk of toxicity. Grapefruit interaction persists for 24 hours; separate consumption by at least 4 hours if unavoidable, but preferable to avoid entirely. Avoid alcohol which can increase hypotension. High-fat meals may reduce absorption of extended-release formulations; take consistently with or without food.
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.
First trimester: Limited human data; animal studies show embryotoxicity. Second/third trimester: May cause fetal hypoxia due to maternal hypotension; risk of preterm labor inhibition. Category C.
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.
Excreted in breast milk; M/P ratio ~0.85. Consider risks versus benefits; monitor infant for hypotension.
No standard dose adjustment required; however, increased plasma volume may reduce drug levels. Titrate to therapeutic effect with careful blood pressure monitoring.
No standard dose adjustment; monitor clinical response and blood pressure; may require lower doses due to vasodilation effects.
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.
Adalat (nifedipine) is a dihydropyridine calcium channel blocker. Use immediate-release capsules only for hypertensive emergencies, not chronic treatment due to risk of reflex tachycardia and unpredictable hypotension. Extended-release formulations are preferred for stable angina and hypertension. Avoid grapefruit juice as it increases nifedipine levels via CYP3A4 inhibition. Monitor for peripheral edema, gingival hyperplasia, and constipation. Contraindicated in cardiogenic shock, severe aortic stenosis, and within 4 weeks of myocardial infarction.
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 extended-release tablets whole; do not crush, chew, or split.,Avoid grapefruit and grapefruit juice while taking this medication.,Report persistent swelling of ankles/feet, gum tenderness or bleeding, or severe dizziness.,Do not stop abruptly; taper under medical supervision to avoid rebound hypertension.,Take at the same time each day; if a dose is missed, skip it if near next dose.,May cause dizziness; avoid driving until you know how it affects you.,Increase fluid and fiber intake to prevent constipation.,Store at room temperature away from light and moisture.
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 ADALAT, 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.. ADALAT is a Calcium Channel Blocker that works by Dihydropyridine calcium channel blocker; inhibits calcium ion influx across cardiac and vascular smooth muscle cells, reducing peripheral vascular resistance and blood pressure.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DILTZAC and ADALAT 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 ADALAT is: 10-20 mg orally three times daily; extended-release: 30-60 mg orally once daily; maximum 120 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 ADALAT 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 . ADALAT is classified as Category C. First trimester: Limited human data; animal studies show embryotoxicity. Second/third trimester: May cause fetal hypoxia due to maternal hypotension; risk of preterm labor inhibiti. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.