Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TAZTIA XT vs CADUET
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 arteries and peripheral arterioles, and reduction of myocardial contractility and heart rate.
Amlodipine: Dihydropyridine calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cell membranes, causing vasodilation and reduced peripheral vascular resistance. Atorvastatin: HMG-Co A reductase inhibitor that competitively inhibits the conversion of HMG-Co A to mevalonate, reducing cholesterol synthesis in the liver.
Hypertension (FDA-approved),Chronic stable angina (FDA-approved),Variant angina (FDA-approved),Atrial fibrillation or atrial flutter (rate control, off-label),Supraventricular tachycardia (off-label)
Hypertension,Coronary artery disease,Hyperlipidemia (as adjunct to diet to reduce elevated total-C, LDL-C, apo B, and TG levels, and to increase HDL-C),Prevention of cardiovascular events in patients with multiple risk factors
Oral, 120 mg or 180 mg once daily. For hypertension, initiate at 120 mg once daily; for angina, initiate at 180 mg once daily. Maximum dose: 360 mg once daily.
CADUET (amlodipine/atorvastatin) is available as tablets of 2.5/10, 2.5/20, 2.5/40, 5/10, 5/20, 5/40, 5/80, 10/10, 10/20, 10/40, and 10/80 mg amlodipine/atorvastatin. Initial dose depends on current antihypertensive and lipid-lowering therapy. Usual starting dose is 5/10 mg orally once daily; titrate at intervals of 2-4 weeks based on blood pressure and LDL-C goals. Maximum daily dose: amlodipine 10 mg; atorvastatin 80 mg.
3-5 hours (immediate-release) for diltiazem; after TAZTIA XT extended-release, effective half-life is approximately 7-9 hours due to prolonged absorption. Clinical context: steady state achieved in 3-5 days.
Amlodipine: terminal half-life 30-50 h (enables once-daily dosing). Atorvastatin: terminal half-life ~14 h, but active metabolites (ortho- and para-hydroxy atorvastatin) have half-life 20-30 h; clinically, pharmacodynamic half-life (HMG-Co A reductase inhibition) is ~20-30 h.
Hepatic via CYP3A4; active metabolite (desacetyldiltiazem).
Amlodipine: Extensively metabolized in the liver via CYP3A4 to inactive metabolites. Atorvastatin: Metabolized in the liver primarily by CYP3A4 to active ortho- and para-hydroxylated metabolites.
Renal (approximately 60% as unchanged drug and metabolites, primarily via glomerular filtration and tubular secretion), biliary/fecal (approximately 30-35%)
Amlodipine: 60% renal (metabolites), 20-25% biliary/fecal. Atorvastatin: 1% renal (unchanged), 90% biliary/fecal (≥70% as metabolites).
70-80% primarily to albumin; also to alpha-1-acid glycoprotein
Amlodipine: ~93% bound to plasma proteins. Atorvastatin: ≥98% bound to plasma proteins (mainly albumin).
3.1-5.3 L/kg (central compartment); large Vd indicates extensive tissue distribution, consistent with high lipophilicity and cardiac/vascular tissue binding.
Amlodipine: Vd ~21 L/kg (large, indicating extensive tissue distribution). Atorvastatin: Vd ~6.2 L/kg (moderately large, suggesting distribution into tissues).
Oral (extended-release): approximately 35-60% due to extensive first-pass hepatic metabolism (cytochrome P450 3A4) with significant interindividual variability. Food may increase bioavailability by up to 20%.
Oral: amlodipine 64-90%; atorvastatin ~14% (low due to first-pass metabolism); food reduces rate but not extent of absorption.
No specific dose adjustment recommended for mild to moderate renal impairment. Use caution in severe renal impairment (Cr Cl <30 m L/min); consider starting at lower dose and titrate slowly.
No dosage adjustment required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). For severe renal impairment (Cr Cl <30 m L/min), use atorvastatin with caution; maximum atorvastatin dose is 20 mg daily. Amlodipine is not dialyzable.
Child-Pugh Class A or B: No specific adjustment, but use caution. Child-Pugh Class C: Contraindicated.
Contraindicated in active liver disease or unexplained persistent elevations of serum transaminases. For Child-Pugh Class A or B hepatic impairment: atorvastatin dose should be reduced; maximum atorvastatin dose is 20 mg daily. Amlodipine clearance is decreased; initial amlodipine dose should be 2.5 mg daily. No data for Child-Pugh Class C; use contraindicated.
Safety and efficacy not established; no pediatric dosing guidelines available.
Not recommended for pediatric patients. Safety and efficacy in children <10 years have not been established. For patients 10-17 years with heterozygous familial hypercholesterolemia, atorvastatin monotherapy is used; CADUET is not indicated.
Start at lower end of dosing range (120 mg once daily) due to increased systemic exposure; titrate slowly based on response and tolerability.
Elderly patients (≥65 years) may have increased sensitivity to amlodipine; start at the lower end of dosing range (2.5 mg amlodipine component). Atorvastatin dose adjustment not required based on age alone. Monitor for hypotension and other adverse effects.
No FDA boxed warning specific to TAZTIA XT; however, the drug class (calcium channel blockers) may have warnings for increased risk of cardiovascular events in certain populations.
HMG-Co A reductase inhibitors (statins) can cause fetal harm; use in pregnant women is contraindicated. Caduet contains atorvastatin; therefore, it is contraindicated in pregnant women.
Heart failure: May worsen symptoms due to negative inotropic effects.,Bradycardia and heart block: Risk especially in elderly or with other AV nodal blockers.,Hypotension: Especially with rapid dose escalation.,Abrupt withdrawal: May cause rebound angina or hypertension.,Hepatic impairment: Reduced metabolism may require dose adjustment.,Concomitant use with beta-blockers: Increased risk of bradycardia and heart block.
Myopathy/Rhabdomyolysis: Risk increased with higher doses, age >65, renal impairment, hypothyroidism, and concurrent use of CYP3A4 inhibitors or other drugs that cause myopathy.,Hepatic effects: Elevated liver enzymes; perform liver function tests before initiation and as clinically indicated.,Fetal toxicity: May cause fetal harm; advise females of reproductive age to use effective contraception.,Peripheral edema: More common with higher doses of amlodipine, especially in females.,Hypotension: In patients with severe aortic stenosis.
Sick sinus syndrome (except with functioning pacemaker),Second- or third-degree AV block (except with pacemaker),Hypotension (systolic <90 mm Hg),Acute myocardial infarction or pulmonary congestion,Known hypersensitivity to diltiazem,Concurrent use with ivabradine
Active liver disease or unexplained persistent elevations of hepatic transaminases,Pregnancy,Breastfeeding (due to potential for serious adverse reactions in nursing infants),Hypersensitivity to amlodipine, atorvastatin, or any component of the formulation
Avoid grapefruit and grapefruit juice as they inhibit CYP3A4 and can increase diltiazem plasma concentrations, elevating risk of bradycardia and hypotension. No other significant food interactions. Administer with or without food.
Avoid grapefruit and grapefruit juice as they increase atorvastatin plasma concentrations and risk of adverse effects. No significant food interactions with amlodipine.
TAZTIA XT (diltiazem) is classified as FDA Pregnancy Category C. In first trimester, animal studies have shown embryofetal toxicity (skeletal abnormalities, fetal mortality) at doses ≥5 times maximum human dose. No adequate human studies in pregnant women; potential risk cannot be ruled out. In second and third trimesters, use may cause uteroplacental hypoperfusion due to maternal hypotension, potentially leading to fetal hypoxia and growth restriction. Case reports associate with preterm labor and low birth weight. Avoid use during pregnancy unless benefit outweighs risk.
FDA Pregnancy Category X. Amlodipine: No evidence of teratogenicity in animal studies, but limited human data; atorvastatin: contraindicated in pregnancy as HMG-Co A reductase inhibitors are associated with fetal abnormalities, including skeletal and CNS defects. First trimester: Atorvastatin is contraindicated; risk of congenital anomalies. Second/third trimester: Avoid exposure; potential for fetal toxicity. Effective contraception required for women of childbearing potential.
Diltiazem is excreted into breast milk at low concentrations. A study reported milk-to-plasma (M/P) ratio of approximately 0.8-1.0. Estimated infant dose is <1% of maternal weight-adjusted dose, considered clinically insignificant. However, due to potential for adverse effects (hypotension, bradycardia) in neonates, caution advised. American Academy of Pediatrics considers diltiazem compatible with breastfeeding. Monitor infant for signs of bradycardia or hypotension.
Excreted in human milk: Amlodipine: present in low levels (M/P ratio approximately 1.0); atorvastatin: unknown. Due to potential for serious adverse reactions in nursing infants (e.g., skeletal muscle toxicity from statins), breastfeeding is contraindicated during therapy. Alternative agents preferred.
No standard dosing adjustments established for pregnancy. However, pregnancy-induced physiological changes (increased plasma volume, renal clearance, and hepatic metabolism) may reduce diltiazem plasma concentrations. Monitor therapeutic effect and consider dose titration based on blood pressure response and heart rate. Limited data suggest that higher doses may be required. Adjust dose cautiously to avoid maternal hypotension, which could compromise uteroplacental perfusion.
Contraindicated during pregnancy; therefore, no dosing adjustments recommended. Discontinue therapy immediately if pregnancy is suspected or confirmed. Pharmacokinetic changes during pregnancy may alter drug metabolism, but no dose adjustments are justified due to teratogenic risk.
TAZTIA XT is a once-daily extended-release formulation of diltiazem (240 mg, 300 mg, 360 mg). Use for hypertension or chronic stable angina. Doses >360 mg are not recommended. Do not crush or chew; the matrix delivery system can cause bezoars. Avoid use in sick sinus syndrome without a pacemaker, second- or third-degree AV block, or hypotension (SBP <90 mm Hg). Monitor for bradycardia and peripheral edema. Abrupt withdrawal may exacerbate angina. Contraindicated with IV beta-blockers or in patients with atrial fibrillation/flutter with accessory bypass tract (e.g., WPW).
CADUET is a fixed-dose combination of amlodipine (a calcium channel blocker) and atorvastatin (a statin) used for hypertension and dyslipidemia. Avoid concomitant use with strong CYP3A4 inhibitors (e.g., clarithromycin, itraconazole) due to increased statin exposure and risk of myopathy. Monitor liver enzymes before and during therapy, and for muscle symptoms. Use with caution in patients with severe renal impairment. Avoid grapefruit juice as it increases atorvastatin levels.
Take TAZTIA XT once daily at approximately the same time every day, with or without food.,Swallow the capsule whole; do not crush, chew, or open it. The empty shell may appear in stool.,Avoid grapefruit and grapefruit juice as it can increase diltiazem levels and risk of side effects.,Do not suddenly stop taking this medication without consulting your doctor, as chest pain or heart attack may worsen.,Report symptoms like slow heartbeat, dizziness, fainting, or swelling of the ankles/feet.,Limit alcohol intake as it can increase dizziness and lower blood pressure.,Warn about interactions with beta-blockers, digoxin, statins, and CYP3A4 inhibitors/inducers.
Take this medication once daily at the same time, with or without food.,Avoid grapefruit and grapefruit juice while taking this medication.,Report unexplained muscle pain, tenderness, or weakness, especially if accompanied by fever or malaise.,Notify your doctor if you become pregnant, plan to become pregnant, or are breastfeeding.,Do not stop taking this medication without consulting your doctor, even if you feel well.
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 TAZTIA XT vs CADUET, answered by our medical review team.
TAZTIA XT 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 arteries and peripheral arterioles, and reduction of myocardial contractility and heart rate.. CADUET is a Calcium Channel Blocker + HMG-CoA Reductase Inhibitor that works by Amlodipine: Dihydropyridine calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cell membranes, causing vasodilation and reduced peripheral vascular resistance. Atorvastatin: HMG-Co A reductase inhibitor that competitively inhibits the conversion of HMG-Co A to mevalonate, reducing cholesterol synthesis in the liver.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TAZTIA XT and CADUET depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of TAZTIA XT is: Oral, 120 mg or 180 mg once daily. For hypertension, initiate at 120 mg once daily; for angina, initiate at 180 mg once daily. Maximum dose: 360 mg once daily.. The standard adult dose of CADUET is: CADUET (amlodipine/atorvastatin) is available as tablets of 2.5/10, 2.5/20, 2.5/40, 5/10, 5/20, 5/40, 5/80, 10/10, 10/20, 10/40, and 10/80 mg amlodipine/atorvastatin. Initial dose depends on current antihypertensive and lipid-lowering therapy. Usual starting dose is 5/10 mg orally once daily; titrate at intervals of 2-4 weeks based on blood pressure and LDL-C goals. Maximum daily dose: amlodipine 10 mg; atorvastatin 80 mg.. 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 TAZTIA XT and CADUET 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. TAZTIA XT is classified as Category C. TAZTIA XT (diltiazem) is classified as FDA Pregnancy Category C. In first trimester, animal studies have shown embryofetal toxicity (skeletal abnormalities, fetal mortality) at dos. CADUET is classified as Category C. FDA Pregnancy Category X. Amlodipine: No evidence of teratogenicity in animal studies, but limited human data; atorvastatin: contraindicated in pregnancy as HMG-CoA reductase inhib. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.