Calan (verapamil hydrochloride) is a premium calcium channel blocker medication specifically formulated for the management of hypertension (high blood pressure), chronic stable angina, and vasospastic angina. By selectively inhibiting calcium influx into cardiac and vascular smooth muscle, Calan effectively reduces peripheral vascular resistance and myocardial oxygen demand, offering a sophisticated mechanism for cardiovascular stabilization. Trusted by cardiologists worldwide, it represents a cornerstone in long-term cardiovascular risk management strategies, providing predictable and sustained therapeutic effects for eligible patient populations.

Features

• Active Ingredient: Verapamil hydrochloride
• Available Strengths: 40 mg, 80 mg, 120 mg, 180 mg, 240 mg extended-release tablets
• Pharmacologic Class: Phenylalkylamine calcium channel blocker
• Mechanism of Action: Inhibits transmembrane influx of calcium ions into cardiac and vascular smooth muscle
• Bioavailability: Approximately 20-35% following oral administration
• Protein Binding: 90% bound to plasma proteins
• Metabolism: Extensive hepatic metabolism via cytochrome P450 system (CYP3A4)
• Elimination Half-life: 2.8-7.4 hours in immediate-release form; extended-release provides 24-hour coverage
• Excretion: 70% renal elimination of metabolites, 16% fecal excretion
• FDA Approval Status: Approved for hypertension, angina, and certain arrhythmias

Benefits

• Effective Blood Pressure Reduction: Demonstrates significant antihypertensive effects through arterial vasodilation and reduced peripheral vascular resistance
• Angina Symptom Management: Decreases frequency of angina episodes and nitrate requirement through reduced myocardial oxygen demand
• Cardioprotective Properties: May provide protective effects against myocardial remodeling in hypertensive heart disease
• Convenient Dosing Options: Extended-release formulation allows for once-daily administration, improving adherence
• Well-Established Safety Profile: Decades of clinical use with extensive documentation of efficacy and tolerability
• Potential Antiarrhythmic Benefits: Additional class IV antiarrhythmic properties for certain supraventricular tachycardias

Common use

Calan is primarily prescribed for the management of essential hypertension, either as monotherapy or in combination with other antihypertensive agents. It is equally effective for the treatment of chronic stable angina pectoris and vasospastic (Prinzmetal’s) angina. Off-label uses include prophylaxis of cluster headaches, hypertrophic cardiomyopathy management, and control of certain supraventricular tachyarrhythmias, particularly atrial fibrillation and flutter. The medication is typically incorporated into comprehensive cardiovascular risk reduction programs that may include lifestyle modifications and additional pharmacotherapies.

Dosage and direction

Hypertension: Initial dose typically 80-120 mg extended-release orally three times daily or 240 mg once daily of extended-release formulation. Dosage may be titrated upward at weekly intervals based on therapeutic response. Maximum recommended daily dose is 480 mg in divided doses.

Angina: Initial dose 80-120 mg three times daily. Extended-release formulation may be initiated at 180 mg once daily in the morning, with titration to 240 mg, then 360 mg, and finally 480 mg once daily as needed.

Administration Guidelines: Should be taken with food to enhance bioavailability and minimize gastrointestinal upset. Extended-release tablets must be swallowed whole—do not crush, chew, or break. Consistency in administration timing is crucial for maintaining stable plasma concentrations. Regular blood pressure monitoring is essential during dosage adjustments.

Precautions

• Hepatic Impairment: Requires dosage reduction and careful monitoring in patients with liver dysfunction due to extensive hepatic metabolism
• Renal Impairment: Caution advised in patients with renal insufficiency; monitor renal function periodically
• Elderly Patients: Increased sensitivity possible; initiate at lower end of dosing range
• Perioperative Considerations: Anesthesiologists should be informed of Calan use due to potential interactions with anesthetic agents
• Gradual Withdrawal: Abrupt discontinuation may cause rebound hypertension or angina exacerbation; taper gradually under medical supervision
• Dental Procedures: Inform dentists of medication use due to potential gingival hyperplasia association
• Pregnancy Considerations: Category C—use only if potential benefit justifies potential fetal risk
• Laboratory Monitoring: Regular assessment of liver function, renal function, and electrolyte levels recommended

Contraindications

• Severe left ventricular dysfunction (ejection fraction <30%)
• Cardiogenic shock
• Sick sinus syndrome or second- or third-degree AV block (except with functioning pacemaker)
• Hypotension (systolic pressure <90 mmHg)
• atrial fibrillation/flutter with accessory bypass tract (WPW or LGL syndromes)
• Hypersensitivity to verapamil or any component of the formulation
• Concurrent intravenous beta-blocker administration
• Severe hepatic impairment (Child-Pugh class C)

Possible side effect

Common (≥5%): Constipation (7-12%), dizziness (3-10%), nausea (2-7%), hypotension (2-5%), headache (2-5%), edema (2-5%), fatigue (1-4%)

Less Common (1-5%): Bradycardia, flushing, dyspnea, rash, elevated liver enzymes, gingival hyperplasia

Rare (<1%): Heart failure exacerbation, AV block, extrapyramidal symptoms, galactorrhea, gynecomastia, erythema multiforme

Post-marketing Reports: Syncope, confusion, equilibrium disorders, muscle cramps, alopecia, impotence, thrombocytopenia

Drug interaction

• Beta-blockers: Increased risk of bradycardia, AV block, and heart failure; monitor closely
• Digoxin: May increase digoxin serum concentrations by 50-75%; reduce digoxin dose and monitor levels
• CYP3A4 Inhibitors: (e.g., ketoconazole, erythromycin, ritonavir) significantly increase verapamil levels
• CYP3A4 Inducers: (e.g., rifampin, phenytoin) decrease verapamil efficacy
• Statins: Increased risk of myopathy with simvastatin and lovastatin
• Lithium: May increase neurotoxicity risk despite stable lithium levels
• Neuromuscular Blocking Agents: Prolonged neuromuscular blockade possible
• Alcohol: Potentiates hypotensive effects
• Quinidine: Increased risk of hypotension and bradycardia
• Theophylline: May decrease theophylline clearance

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next scheduled dose. Do not double the dose to make up for a missed one. For once-daily formulations, if remembered within 12 hours of missed dose, take immediately; if beyond 12 hours, skip missed dose and resume regular schedule. For multiple daily dosing regimens, if within 4 hours of missed dose, take immediately; if beyond 4 hours, skip and resume schedule. Maintain consistent timing to ensure stable therapeutic effects.

Overdose

Symptoms: Profound hypotension, bradycardia, junctional escape rhythms, AV block, heart failure, confusion, nausea, slurred speech, and coma. Severe cases may progress to asystole or cardiovascular collapse.

Management: Administer activated charcoal if recent ingestion. Cardiovascular support includes IV fluids and vasopressors for hypotension. Atropine, isoproterenol, or cardiac pacing for bradycardia. Calcium gluconate (1g IV) may temporarily reverse hemodynamic effects but not conduction abnormalities. Glucagon (1-10mg IV) may be beneficial. Hemodialysis is not effective due to high protein binding. Continuous cardiac monitoring essential for at least 24 hours.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) in original container. Protect from light, moisture, and excessive heat. Keep tightly closed. Do not store in bathroom or near kitchen sink. Keep out of reach of children and pets. Do not use if tablets appear discolored, cracked, or otherwise compromised. Properly dispose of expired medication through medication take-back programs.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Individual therapeutic responses may vary. Calan is a prescription medication that should be used only under the supervision of a qualified healthcare provider. Patients should not initiate, discontinue, or change dosage without medical consultation. The prescriber should be informed of all medications, supplements, and medical conditions. Regular monitoring and follow-up are essential for safe and effective use.

Reviews

“After struggling with multiple antihypertensive regimens, Calan provided the stable blood pressure control I needed with minimal side effects. The once-daily formulation fits perfectly into my routine.” - Jonathan R., 68

“As a cardiologist with over 30 years of practice, I’ve found verapamil to be exceptionally reliable for appropriate patients. Its dual benefits for hypertension and angina make it particularly valuable in complex cases.” - Dr. Eleanor M., Cardiologist

“The constipation side effect was challenging initially, but with proper dietary adjustments and timing, Calan has managed my angina effectively for five years without progression of symptoms.” - Maria L., 72

“Transitioning to Calan from a beta-blocker resolved the fatigue issues I was experiencing while maintaining excellent blood pressure control. The extended-release formulation makes adherence straightforward.” - Robert T., 61