Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CARDIZEM SR vs ADALAT CC
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 cell membranes during depolarization, leading to negative inotropic, chronotropic, and dromotropic effects, and vasodilation.
Nifedipine, a dihydropyridine calcium channel blocker, inhibits calcium ion influx across cardiac and smooth muscle cell membranes, leading to vasodilation and decreased myocardial contractility.
Hypertension,Angina pectoris due to coronary artery spasm (Prinzmetal's variant angina),Chronic stable angina (classic effort-associated angina)
Hypertension,Chronic stable angina,Vasospastic angina (Prinzmetal's angina)
Oral: Initial dose 60-120 mg twice daily; titrate to maximum 360 mg/day divided into two doses.
30 mg orally once daily; may titrate to 60 mg or 90 mg once daily based on response and tolerability.
3.0-4.5 hours for diltiazem; metabolites (e.g., desacetyldiltiazem) up to 10 hours. Clinical context: dosing interval adjustment in hepatic impairment.
Terminal elimination half-life: 7-10 hours; clinical context: sustained-release formulation provides therapeutic concentrations over 24 hours with once-daily dosing, but half-life does not directly reflect drug effect duration due to slow absorption.
Primarily hepatic via CYP3A4; undergoes extensive first-pass metabolism.
Hepatic metabolism via CYP3A4; nifedipine is converted to inactive metabolites.
Renal: 2-4% unchanged; hepatic metabolism: ~60-70% (including active metabolites); fecal: ~30-40%.
Renal: 70-80% as metabolites, fecal: 15-20% as metabolites, biliary: minimal (<5% unchanged).
Approximately 70-80%, primarily to albumin and alpha-1-acid glycoprotein.
92-98% bound primarily to albumin.
3.1-5.1 L/kg; large Vd indicates extensive tissue distribution (e.g., myocardium, vascular smooth muscle).
1.2-1.6 L/kg; clinical meaning: indicates extensive tissue distribution, with higher concentrations in organs such as liver and kidney, and lower in brain due to P-glycoprotein efflux.
Oral (sustained-release): approximately 40-50% due to first-pass metabolism; variable among formulations.
65-90% after oral administration; absolute bioavailability of nifedipine in ADALAT CC: approximately 65% due to first-pass metabolism in liver and gut wall.
For GFR < 10 m L/min: Use with caution and reduce dose by 25-50%; consider extended dosing interval.
No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (Cr Cl <30 m L/min), start at 30 mg once daily and titrate cautiously.
Child-Pugh Class B: Reduce dose by 50%; Child-Pugh Class C: Use not recommended.
For mild to moderate hepatic impairment (Child-Pugh A or B), reduce initial dose to 30 mg once daily; for severe impairment (Child-Pugh C), contraindicated or use with extreme caution.
Safety and efficacy not established; no specific weight-based dosing guidelines available.
Safety and efficacy not established; use is not recommended in pediatric patients.
Initial dose 60 mg twice daily; titrate slowly due to increased risk of bradycardia and hypotension.
Initiate at 30 mg once daily; titrate slowly due to increased risk of hypotension and higher drug exposure. Monitor closely.
None.
No FDA black box warning.
Cardiac conduction abnormalities: bradycardia, AV block, sick sinus syndrome,Heart failure: use with caution in patients with compromised ventricular function,Hypotension,Hepatic impairment,Concomitant use with beta-blockers may increase risk of bradycardia and AV block,Abrupt discontinuation may exacerbate angina
Beta-blocker withdrawal: taper if discontinuing; exacerbation of angina,Heart failure: use caution in patients with severe left ventricular dysfunction,Hepatic impairment: reduce dose,Peripheral edema: may occur; differentiate from worsening heart failure,Monitor blood pressure during initiation and titration
Sick sinus syndrome (except in patients with a functioning artificial ventricular pacemaker),Second- or third-degree AV block (except in patients with a functioning artificial ventricular pacemaker),Hypotension (systolic blood pressure < 90 mm Hg),Acute myocardial infarction with pulmonary congestion,Known hypersensitivity to diltiazem
Hypersensitivity to nifedipine or any component,Cardiogenic shock,Concurrent use with strong CYP3A4 inducers (e.g., rifampin)
Grapefruit and grapefruit juice increase diltiazem levels by inhibiting CYP3A4 metabolism; avoid concurrent use. No other significant food restrictions. Alcohol may enhance hypotensive effects and increase risk of dizziness.
Avoid grapefruit and grapefruit juice as they inhibit CYP3A4 metabolism, raising nifedipine levels and risk of toxicity. High-fat meals may increase absorption; take consistently with respect to meals. Avoid alcohol as it may exacerbate hypotension.
FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, diltiazem has been shown to cause embryofetal toxicity (skeletal abnormalities, reduced fetal weight) at doses 5-10 times the maximum recommended human dose. Risk to fetus cannot be ruled out; use only if potential benefit justifies potential risk.
Adalat CC (nifedipine) is an extended-release formulation of nifedipine, a dihydropyridine calcium channel blocker. In animal studies, nifedipine has been associated with embryotoxicity, fetotoxicity, and teratogenicity (e.g., digital anomalies, cleft palate) at doses several times the maximum recommended human dose. In humans, data are limited but there is no clear evidence of a significant increase in major congenital malformations. First trimester exposure is not strongly associated with major defects; however, some studies suggest a possible small increase in oral clefts. Second and third trimester use may cause maternal hypotension and subsequent fetal distress (e.g., reduced uteroplacental perfusion). Use near term may theoretically inhibit labor, but nifedipine is used as a tocolytic for preterm labor. Overall, the risk is considered low; however, fetal monitoring is recommended if used in pregnancy. FDA Pregnancy Category C (prior to 2015 categorization).
Diltiazem is excreted into human breast milk at low concentrations. Estimated infant dose is <1% of maternal weight-adjusted dose. M/P ratio not established. Although risk to nursing infant is likely low, caution is advised. Monitor infant for bradycardia, hypotension, and feeding difficulties.
Nifedipine is excreted into human breast milk in small amounts. The milk-to-plasma (M/P) ratio is approximately 0.56 to 1.0 based on limited data. The estimated daily infant dose via milk is less than 5% of the maternal weight-adjusted dose, which is considered clinically insignificant. No adverse effects have been reported in breastfed infants. However, caution is advised, especially with high maternal doses or prolonged use. The American Academy of Pediatrics considers nifedipine compatible with breastfeeding.
No specific dose adjustment guidelines for pregnancy; however, pharmacokinetic changes in pregnancy (increased volume of distribution, altered hepatic metabolism) may require dose titration based on clinical response and tolerability. Start at lowest effective dose and monitor closely.
Pregnancy may alter the pharmacokinetics of nifedipine due to increased plasma volume and altered hepatic metabolism. However, specific dosing adjustments for Adalat CC in pregnancy are not well established. In clinical practice, dosing for hypertension in pregnancy (e.g., preeclampsia) often uses immediate-release nifedipine, not extended-release. For Adalat CC, the same dosing as in non-pregnant adults (30-90 mg once daily) is typically used, but titration should be cautious to avoid maternal hypotension. No formal dose adjustment is recommended, but careful monitoring and individualized titration are advised.
Cardizem SR is a sustained-release calcium channel blocker indicated for hypertension and angina. Onset: 2-3 hours, duration: 12-24 hours. Avoid concurrent use with beta-blockers due to risk of bradycardia and heart block. Contraindicated in sick sinus syndrome (unless pacemaker), second- or third-degree AV block, hypotension (SBP <90 mm Hg), and acute MI with pulmonary congestion. Monitor liver function and renal function; dose adjustment needed in hepatic impairment. Use caution in patients with decreased left ventricular function (ejection fraction <40%). Do not crush or chew capsules; swallow whole.
Adalat CC (nifedipine extended-release) is a dihydropyridine calcium channel blocker used primarily for hypertension. Avoid in patients with unstable angina or within 4 weeks of myocardial infarction due to reflex tachycardia risk. May cause peripheral edema, especially in higher doses; consider adding an ACE inhibitor if edema is problematic. CYP3A4 inhibitors (e.g., grapefruit juice, macrolides, azole antifungals) significantly increase nifedipine levels; avoid coadministration. Tablet shell may appear intact in stool; this is normal.
Take this medication exactly as prescribed, with or without food, at the same time each day.,Swallow the capsule whole; do not crush, chew, or open it.,Avoid grapefruit and grapefruit juice while on this medication; they can increase the drug's effect and risk of side effects.,Do not stop taking this medication suddenly; abrupt discontinuation may worsen chest pain or increase blood pressure.,Contact your healthcare provider if you experience slow heartbeat, fainting, dizziness, shortness of breath, or swelling of the legs/ankles.,Limit alcohol consumption as it may increase the risk of side effects such as dizziness or fainting.,Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding.,Keep all appointments to check your blood pressure and heart rhythm.
Swallow the tablet whole; do not crush or chew.,Do not consume grapefruit or grapefruit juice while taking this medication.,May cause dizziness or lightheadedness; avoid driving if affected.,Notify your doctor if you experience rapid heartbeat, swelling in the ankles or feet, or prolonged erections.,Take exactly as prescribed; do not skip doses or stop abruptly without consulting your doctor.
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 SR vs ADALAT CC, answered by our medical review team.
CARDIZEM SR is a Calcium Channel Blocker that works by Diltiazem inhibits calcium ion influx across cardiac and vascular smooth muscle cell membranes during depolarization, leading to negative inotropic, chronotropic, and dromotropic effects, and vasodilation.. ADALAT CC is a Calcium Channel Blocker that works by Nifedipine, a dihydropyridine calcium channel blocker, inhibits calcium ion influx across cardiac and smooth muscle cell membranes, leading to vasodilation and decreased myocardial contractility.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CARDIZEM SR and ADALAT CC 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 SR is: Oral: Initial dose 60-120 mg twice daily; titrate to maximum 360 mg/day divided into two doses.. The standard adult dose of ADALAT CC is: 30 mg orally once daily; may titrate to 60 mg or 90 mg once daily based on response and tolerability.. 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 SR and ADALAT CC 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 SR is classified as Category C. FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, diltiazem has been shown to cause embryofetal toxicity (skeletal abnormalities, reduced fetal we. ADALAT CC is classified as Category C. Adalat CC (nifedipine) is an extended-release formulation of nifedipine, a dihydropyridine calcium channel blocker. In animal studies, nifedipine has been associated with embryotox. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.