Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
KATERZIA vs CALAN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
KATERZIA (bosentan) is an endothelin receptor antagonist (ERA) that blocks endothelin-1 (ET-1) from binding to ETA and ETB receptors in the endothelium and vascular smooth muscle. This inhibits ET-1-mediated vasoconstriction and smooth muscle proliferation, reducing pulmonary vascular resistance and pulmonary arterial pressure.
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.
Treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise ability and decrease clinical worsening in patients with WHO class II–IV symptoms,Off-label: Treatment of digital ulcers in systemic sclerosis; prevention of recurrence of digital ulcers; management of inoperable chronic thromboembolic pulmonary hypertension
Angina pectoris (chronic stable, vasospastic, unstable),Essential hypertension,Supraventricular tachyarrhythmias (e.g., atrial fibrillation, atrial flutter, PSVT)
5 mg orally once daily for 21 days, then 7 days off, repeated in 28-day cycles.
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 elimination half-life is approximately 9-12 hours in healthy adults. In patients with hypertension or hepatic impairment, half-life may be prolonged up to 15-20 hours, necessitating dose adjustment.
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.
Primarily metabolized by CYP2C9 and CYP3A4 to three major metabolites (Ro 48-5033, Ro 47-8634, Ro 64-1056). Induces CYP2C9 and CYP3A4; also induces CYP2C19.
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 elimination accounts for approximately 60-80% of the administered dose, predominantly as unchanged drug via glomerular filtration and active tubular secretion. Biliary/fecal excretion is minimal, <5%.
Approximately 70% renal (3-4% unchanged, remainder as metabolites) and 25% biliary/fecal.
Approximately 95-98% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. High binding limits tissue distribution and affects free drug concentration.
Approximately 90% bound to plasma proteins, primarily albumin.
Volume of distribution is approximately 0.7-1.2 L/kg (range 50-80 L for a 70 kg adult), indicating moderate tissue distribution beyond plasma volume.
Vd 4-5 L/kg; indicates extensive tissue distribution beyond plasma volume.
Oral bioavailability is approximately 30-40% due to extensive first-pass hepatic metabolism. Food may reduce bioavailability by 20-30%, so dosing should be consistent with respect to meals.
Oral bioavailability is 20-35% due to extensive first-pass hepatic metabolism; IV bioavailability is 100%.
No dose adjustment required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). Not recommended in severe renal impairment (Cr Cl <30 m L/min) or end-stage renal disease.
Cr Cl <30 m L/min: reduce dose by 50% and monitor carefully.
Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose to 5 mg orally once daily for 21 days, then 7 days off. 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 in pediatric patients.
Oral: 4-8 mg/kg/day in 3 divided doses; IV: 0.1-0.3 mg/kg over 2 minutes, max 5 mg.
No specific dose adjustment required; monitor for adverse events due to potential age-related renal and hepatic decline.
Start at lowest dose (e.g., 40 mg 3 times daily) and titrate slowly; monitor for hypotension and bradycardia.
WARNING: HEPATOTOXICITY. Bosentan can cause serious hepatic injury, including acute liver failure, requiring baseline and monthly monitoring of liver enzymes. Discontinue if ALT/AST >3x ULN accompanied by symptoms or bilirubin >2x ULN.
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).
Hepatotoxicity (monitor LFTs monthly), hepatorenal syndrome; peripheral edema; fluid retention; may cause hypotension; pulmonary veno-occlusive disease (PVOD) may cause pulmonary edema; decreases hemoglobin and hematocrit (monitor at 1 and 3 months, then every 3 months); decreases sperm count; reduces efficacy of hormonal contraceptives (use alternative contraception); caution in hepatic impairment (Child-Pugh Class A; contraindicated in moderate to severe impairment); caution in elderly; not recommended in patients with severe anemia.
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.
Absolute: Hypersensitivity to bosentan or any component; moderate to severe hepatic impairment (Child-Pugh Class B or C); baseline AST/ALT >3× ULN; concomitant use with cyclosporine A (increases bosentan levels and hepatotoxicity); concomitant use with glyburide (increases risk of liver enzyme elevations); pregnancy (teratogenic in animals – can cause birth defects; must exclude pregnancy before initiation and monthly thereafter).
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.
Take with food to improve tolerability and reduce gastrointestinal adverse effects. Avoid grapefruit juice as it may increase treprostinil exposure. Avoid alcohol as it may exacerbate vasodilation and hypotension.
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: animal studies show fetal toxicity; no adequate human data. Second/third trimester: may cause fetal renal impairment, oligohydramnios, and skull ossification defects due to direct renin-angiotensin system inhibition.
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.
No human data; M/P ratio unknown. Excreted in rat milk. Due to potential risk of hypotension and renal impairment in nursing infants, discontinue drug or breastfeeding, considering importance to mother.
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.
No specific dose adjustments established for pregnancy. However, due to increased plasma volume, efficacy may be reduced; monitor therapeutic response. Contraindicated in pregnancy; avoid use.
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.
KATERZIA (oral treprostinil) is a prostacyclin analogue used for pulmonary arterial hypertension (PAH). Monitor for prostacyclin-related side effects (headache, nausea, diarrhea, jaw pain, flushing). Dose titration is critical; increase by 0.25 mg BID or 0.125 mg TID every 3-4 days as tolerated. Avoid abrupt discontinuation due to risk of rebound pulmonary hypertension. Use with caution in patients with hepatic impairment; reduce starting dose in moderate impairment.
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 KATERZIA exactly as prescribed, with food to reduce gastrointestinal side effects.,Do not stop taking this medication suddenly; consult your doctor before making any changes.,Common side effects include headache, nausea, diarrhea, jaw pain, and flushing; report severe or persistent symptoms.,Avoid alcohol and grapefruit juice as they may interact with the medication.,Store tablets in the original container at room temperature, away from moisture and light.,If you miss a dose, skip it and take the next dose at the scheduled time; do not double dose.,Inform your healthcare provider of all medications you are taking, especially antihypertensives, anticoagulants, and NSAIDs.
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 KATERZIA vs CALAN, answered by our medical review team.
KATERZIA is a Calcium Channel Blocker that works by KATERZIA (bosentan) is an endothelin receptor antagonist (ERA) that blocks endothelin-1 (ET-1) from binding to ETA and ETB receptors in the endothelium and vascular smooth muscle. This inhibits ET-1-mediated vasoconstriction and smooth muscle proliferation, reducing pulmonary vascular resistance and pulmonary arterial pressure.. 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 KATERZIA 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 KATERZIA is: 5 mg orally once daily for 21 days, then 7 days off, repeated in 28-day cycles.. 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 KATERZIA 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. KATERZIA is classified as Category C. Pregnancy Category C. First trimester: animal studies show fetal toxicity; no adequate human data. Second/third trimester: may cause fetal renal impairment, oligohydramnios, and sk. 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.