Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CARDIZEM CD 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 is a calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cell membranes, resulting in dilation of coronary arteries and peripheral arterioles, and decreased myocardial contractility and conduction velocity.
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,Chronic stable angina,Variant angina
Hypertension,Chronic stable angina,Vasospastic angina (Prinzmetal's angina)
Hypertension: 180-360 mg once daily orally. Angina: 120-360 mg once daily orally. Maximum dose: 480 mg/day.
30 mg orally once daily; may titrate to 60 mg or 90 mg once daily based on response and tolerability.
Terminal elimination half-life: 6-8 hours (single dose), prolonged to 10-15 hours with multiple dosing or in elderly/hepatic impairment. Clinical context: Therapeutic steady-state achieved in 2-4 days.
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.
Hepatic via CYP3A4; also undergoes deacetylation; substrate of P-glycoprotein.
Hepatic metabolism via CYP3A4; nifedipine is converted to inactive metabolites.
Renal: ~2-4% (unchanged), Hepatic metabolism to multiple metabolites; ~65% renal (metabolites), ~35% fecal/biliary. Total clearance: 5-7 m L/kg/min.
Renal: 70-80% as metabolites, fecal: 15-20% as metabolites, biliary: minimal (<5% unchanged).
70-80% bound primarily to albumin (70%), also alpha-1 acid glycoprotein (10%). Binding saturable at high concentrations.
92-98% bound primarily to albumin.
Approximately 5.3 L/kg. Meaning: Extensive tissue distribution (3-5 L/kg); reflects high lipophilicity and wide distribution beyond plasma.
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.
Extended-release (Cardizem CD): ~40% (range 35-45%) due to extensive first-pass metabolism. Immediate-release: ~40-50%. IV: 100%.
65-90% after oral administration; absolute bioavailability of nifedipine in ADALAT CC: approximately 65% due to first-pass metabolism in liver and gut wall.
No specific GFR-based adjustment required, but use caution in severe renal impairment (Cr Cl <30 m L/min).
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 A: start with 120 mg once daily. Child-Pugh Class B: start with 120 mg once daily, titrate cautiously. Child-Pugh Class C: contraindicated.
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.
Not approved for pediatric use; safety and efficacy not established.
Safety and efficacy not established; use is not recommended in pediatric patients.
Start at lower end of dosing range (120 mg once daily) due to increased risk of hypotension and bradycardia; titrate slowly.
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.
May cause hypotension,Risk of heart failure exacerbation in patients with impaired ventricular function,May slow AV conduction, leading to bradycardia or AV block,Hepatic and renal impairment caution,May exacerbate symptoms in patients with hypertrophic cardiomyopathy
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 presence of functioning ventricular pacemaker),Second- or third-degree AV block (except in presence of functioning ventricular pacemaker),Hypotension (systolic < 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 juice may increase diltiazem serum concentrations; avoid concurrent ingestion. Alcohol may enhance hypotensive effects. No significant food restrictions otherwise.
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.
Diltiazem, the active ingredient in Cardizem CD, is classified as Pregnancy Category C. Animal studies have demonstrated embryotoxicity and teratogenicity (skeletal abnormalities) at doses 5-10 times the maximum recommended human dose. There are no adequate and well-controlled studies in pregnant women. In humans, exposure during the first trimester may be associated with a small increased risk of congenital anomalies, particularly cardiac defects, though data are limited. During the second and third trimesters, use may be associated with potential risks of fetal growth restriction and preterm labor due to maternal hypotension and decreased uteroplacental perfusion. The drug should only be used if the potential benefit justifies the potential risk to the fetus.
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 milk at low concentrations; the milk-to-plasma (M/P) ratio is approximately 0.8. Limited data suggest that the estimated infant daily dose is less than 1% of the maternal weight-adjusted dose. While adverse effects in breastfed infants have not been reported, caution is advised due to potential for cardiovascular effects. The manufacturer recommends discontinuing breastfeeding or the drug, considering the importance of the drug to the mother.
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.
Pregnancy-induced increases in plasma volume and hepatic metabolism may reduce diltiazem concentrations, potentially requiring dose adjustments. However, specific pharmacokinetic studies in pregnant women are lacking. Clinical monitoring of therapeutic effect (e.g., blood pressure control) should guide dosing; gradual titration is recommended, and doses may need to be increased based on response. Avoid abrupt discontinuation.
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.
Diltiazem (Cardizem CD) is a nondihydropyridine calcium channel blocker; use with caution in patients with systolic heart failure (HFr EF) due to negative inotropic effects. Avoid concurrent use with beta-blockers due to risk of bradycardia and heart block. May increase dugoxin levels; monitor digoxin levels. Contraindicated in sick sinus syndrome or second/third-degree AV block without pacemaker. Also inhibits CYP3A4; monitor for interactions with statins (e.g., simvastatin dose limit 10 mg).
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 capsule whole; do not crush or chew. May be taken without regard to meals.,Do not stop abruptly; gradual taper advised to avoid rebound hypertension or ischemia.,Report symptoms of bradycardia (dizziness, fainting) or heart failure (swelling, shortness of breath).,Avoid grapefruit juice as it may increase drug levels and risk of side effects.,Use sunscreen and protective clothing due to possible photosensitivity.
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 CD vs ADALAT CC, answered by our medical review team.
CARDIZEM CD 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 cell membranes, resulting in dilation of coronary arteries and peripheral arterioles, and decreased myocardial contractility and conduction velocity.. 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 CD 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 CD is: Hypertension: 180-360 mg once daily orally. Angina: 120-360 mg once daily orally. Maximum dose: 480 mg/day.. 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 CD 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 CD is classified as Category C. Diltiazem, the active ingredient in Cardizem CD, is classified as Pregnancy Category C. Animal studies have demonstrated embryotoxicity and teratogenicity (skeletal abnormalities) . 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.