Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
SULAR vs CALAN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Nisoldipine is a dihydropyridine calcium channel blocker that inhibits the influx of calcium ions through L-type calcium channels in vascular smooth muscle and cardiac muscle. This leads to vasodilation, reduced peripheral vascular resistance, and decreased myocardial oxygen demand.
Verapamil inhibits calcium ion influx through voltage-gated L-type calcium channels in cardiac and vascular smooth muscle, leading to decreased myocardial contractility, slowed AV conduction, and vasodilation.
Management of hypertension, alone or in combination with other antihypertensive agents
Angina pectoris (chronic stable, vasospastic, unstable),Essential hypertension,Supraventricular tachyarrhythmias (e.g., atrial fibrillation, atrial flutter, PSVT)
10-20 mg orally once daily; maximum 60 mg/day.
Initial: 80-120 mg orally 3 times daily; maintenance: 240-480 mg/day in 3-4 divided doses. IV: 5-10 mg over 2 minutes, may repeat after 15-30 minutes.
Terminal half-life of 24-50 hours, mean ~34 hours; extended in elderly and hepatic impairment, dose adjustment may be needed
Terminal elimination half-life is 3-7 hours for immediate-release; can be prolonged to 12-16 hours with sustained-release due to slow absorption; increased in hepatic impairment.
Extensively metabolized in the liver via CYP3A4; undergoes first-pass metabolism. Metabolites are inactive.
Extensively metabolized in the liver via CYP3A4, CYP1A2, and CYP2C8 isoenzymes; undergoes N-dealkylation and O-demethylation; first-pass metabolism results in low bioavailability (20-35%).
Renal: 50-60% as metabolites, 10% as unchanged drug; Fecal: ~35%; Biliary: <5%
Approximately 70% renal (3-4% unchanged, remainder as metabolites) and 25% biliary/fecal.
>95% bound to plasma proteins (albumin and alpha-1-acid glycoprotein)
Approximately 90% bound to plasma proteins, primarily albumin.
3-10 L/kg; extensive tissue distribution, slow equilibration
Vd 4-5 L/kg; indicates extensive tissue distribution beyond plasma volume.
Oral: 65-90% (first-pass metabolism); extended-release formulation provides consistent absorption
Oral bioavailability is 20-35% due to extensive first-pass hepatic metabolism; IV bioavailability is 100%.
No adjustment for GFR ≥30 m L/min. For GFR <30 m L/min, initiate at 5 mg once daily.
Cr Cl <30 m L/min: reduce dose by 50% and monitor carefully.
Child-Pugh A: 5 mg once daily. Child-Pugh B: 2.5 mg once daily. Child-Pugh C: not recommended.
Child-Pugh A: 50% of normal dose; Child-Pugh B: 25% of normal dose; Child-Pugh C: contraindicated or use with extreme caution.
Safety and efficacy not established; no approved dosing.
Oral: 4-8 mg/kg/day in 3 divided doses; IV: 0.1-0.3 mg/kg over 2 minutes, max 5 mg.
Initiate at 5 mg once daily; titrate cautiously due to increased sensitivity and risk of hypotension.
Start at lowest dose (e.g., 40 mg 3 times daily) and titrate slowly; monitor for hypotension and bradycardia.
None
Contains verapamil hydrochloride. Risk of serious adverse effects including hypotension, bradycardia, AV block, and cardiac arrest. Must not be administered to patients with severe left ventricular dysfunction, cardiogenic shock, or sick sinus syndrome (unless paced).
Increased angina and/or myocardial infarction upon initiation or dose titration; caution in patients with heart failure, aortic stenosis, or significant left ventricular dysfunction; may cause hypotension; caution in patients with hepatic impairment; grapefruit juice increases nisoldipine levels and should be avoided; drug interactions with CYP3A4 inhibitors and inducers.
May cause hypotension, bradycardia, AV block, and exacerbation of heart failure. Avoid in patients with pre-existing conduction abnormalities. Use caution with beta-blockers, digoxin, and CYP3A4 inhibitors. Abrupt withdrawal may exacerbate angina. May increase lithium and carbamazepine levels.
Hypersensitivity to nisoldipine or any dihydropyridine calcium channel blocker; concomitant administration with strong CYP3A4 inhibitors (e.g., clarithromycin, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir).
Severe left ventricular dysfunction, cardiogenic shock, sick sinus syndrome (without pacemaker), second- or third-degree AV block (without pacemaker), atrial flutter/fibrillation with accessory bypass tract (e.g., WPW syndrome), concurrent use of IV beta-blockers.
Avoid grapefruit and grapefruit juice as they increase nisoldipine serum concentrations by inhibiting CYP3A4 metabolism. Concomitant intake of high-fat meals (e.g., >50% fat) can increase the rate and extent of absorption; advise taking consistently with or without food. St. John's wort may reduce efficacy due to CYP3A4 induction.
Avoid grapefruit and grapefruit juice as they inhibit CYP3A4 metabolism, increasing verapamil levels and risk of toxicity. Limit alcohol intake as it may enhance hypotensive effects. High-fat meals may delay absorption but not extent; take consistently with regard to meals.
Pregnancy Category C. First trimester: No adequate studies; potential for fetal harm based on animal data. Second and third trimesters: Risk of fetal hypotension, oligohydramnios, and neonatal renal failure. Avoid use during pregnancy unless benefit outweighs risk.
First trimester: No increased risk of major malformations observed in human studies; animal studies show fetal toxicity at high doses. Second and third trimesters: May cause fetal bradycardia, hypotension, and impaired placental perfusion; avoid use for pregnancy-induced hypertension due to risk of fetal hypoxia.
Excreted in human milk; M/P ratio unknown. Effects on infant unknown. Use with caution, especially in preterm infants or those with compromised renal function.
Verapamil (CALAN) is excreted into breast milk; M/P ratio approximately 0.6. The relative infant dose is low (estimated <5% of maternal weight-adjusted dose). No adverse effects reported in breastfed infants. Caution in preterm infants or those with renal impairment.
Increased plasma volume and hepatic metabolism in pregnancy may require dose increase. Monitor clinical response and titrate accordingly.
Pregnancy may increase clearance of verapamil; monitoring of therapeutic effect advised. Dose may need adjustment based on clinical response. Avoid use in pregnancy-induced hypertension.
Nisoldipine (Sular) is a dihydropyridine calcium channel blocker with high vascular selectivity; avoid use in patients with unstable angina or recent MI due to reflex tachycardia risk. Do not administer with grapefruit juice as it significantly increases drug exposure. Monitor for peripheral edema, especially in the elderly. Use cautiously in patients with severe aortic stenosis or hepatic impairment. May be taken without regard to meals, but avoid high-fat meals which can increase absorption.
Calan (verapamil) is a class IV antiarrhythmic and calcium channel blocker. Use caution in patients with hepatic impairment due to reduced clearance; dose adjustment may be needed. Avoid in patients with pre-existing bradycardia, second- or third-degree AV block, or sick sinus syndrome unless a pacemaker is present. May increase digoxin levels; monitor digoxin concentrations. Use with caution in patients with hypertrophic cardiomyopathy. For IV administration, have calcium gluconate available to reverse hypotension or bradycardia. Not recommended for use in acute myocardial infarction or cardiogenic shock.
Take exactly as prescribed; do not crush or chew extended-release tablets.,Avoid grapefruit and grapefruit juice while taking this medication.,Do not stop abruptly without consulting your doctor; may worsen chest pain or blood pressure.,You may experience dizziness or lightheadedness; rise slowly from sitting or lying positions.,Notify your doctor if you develop swelling in your ankles or feet, rapid heartbeat, or severe dizziness.,Avoid alcohol as it can increase the risk of low blood pressure and dizziness.
Take exactly as prescribed; do not skip doses or stop abruptly without consulting your doctor.,Avoid grapefruit juice as it can increase verapamil levels and risk of side effects.,If you miss a dose, take it as soon as you remember unless it is almost time for the next dose; do not double the dose.,Avoid alcohol as it may worsen side effects like dizziness or low blood pressure.,Report symptoms of bradycardia (slow heart rate), palpitations, shortness of breath, or swelling of ankles/feet.,This medication may cause dizziness; avoid driving or operating machinery until you know how it affects you.,Do not consume grapefruit or its juice during treatment.,Keep a regular medication schedule and do not change brands without doctor approval.
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 SULAR vs CALAN, answered by our medical review team.
SULAR is a Calcium Channel Blocker that works by Nisoldipine is a dihydropyridine calcium channel blocker that inhibits the influx of calcium ions through L-type calcium channels in vascular smooth muscle and cardiac muscle. This leads to vasodilation, reduced peripheral vascular resistance, and decreased myocardial oxygen demand.. CALAN is a Calcium Channel Blocker that works by Verapamil inhibits calcium ion influx through voltage-gated L-type calcium channels in cardiac and vascular smooth muscle, leading to decreased myocardial contractility, slowed AV conduction, and vasodilation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between SULAR and CALAN 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 SULAR is: 10-20 mg orally once daily; maximum 60 mg/day.. The standard adult dose of CALAN is: Initial: 80-120 mg orally 3 times daily; maintenance: 240-480 mg/day in 3-4 divided doses. IV: 5-10 mg over 2 minutes, may repeat after 15-30 minutes.. 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 SULAR and CALAN 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. SULAR is classified as Category C. Pregnancy Category C. First trimester: No adequate studies; potential for fetal harm based on animal data. Second and third trimesters: Risk of fetal hypotension, oligohydramnios, . CALAN is classified as Category C. First trimester: No increased risk of major malformations observed in human studies; animal studies show fetal toxicity at high doses. Second and third trimesters: May cause fetal . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.