Buy Calan Sr

Calan Sr

Calan SR: Verapamil Pill Overview

Calan SR is a brand-name medication that contains verapamil as its active ingredient. It belongs to the Heart & Blood Pressure therapeutic class and is available in 120 mg and 240 mg sustained-release tablets. In Hong Kong, Calan SR is a prescription-only medicine regulated by the Department of Health under the Medicines and Poisons Ordinance.

How Verapamil Works in the Body

Verapamil is a calcium-channel blocker that primarily targets L-type calcium channels in cardiac and smooth-muscle cells. By inhibiting calcium influx:

• Heart rate slows because the drug reduces the automaticity of the sino-atrial node.
• AV-node conduction is suppressed, which is useful for certain arrhythmias.
• Vascular smooth muscle relaxes, leading to dilation of arterial vessels and a modest reduction in systemic blood pressure.

The sustained-release formulation (Calan SR) releases the drug gradually, providing a more stable plasma concentration over 24 hours compared with immediate-release tablets. This steady effect helps maintain consistent heart-rate control and blood-pressure reduction throughout the day.

Conditions Treated with Calan SR

Calan SR is approved by the Hong Kong Department of Health for the following indications:

• Management of hypertension (high blood pressure) when a calcium-channel blocker is appropriate.
• Control of angina pectoris (chest pain caused by reduced coronary blood flow).
• Treatment of certain cardiac arrhythmias, especially supraventricular tachycardia and atrial fibrillation, by slowing AV-node conduction.

These uses stem from ververapamil’s combined effects on heart rate, contractility, and vascular tone.

Patient Suitability and Contraindications

Who Should Use Calan SR?

• Adults diagnosed with hypertension, stable angina, or specific supraventricular arrhythmias.
• Patients whose healthcare provider determines that a calcium-channel blocker is suitable after evaluating heart function, liver and kidney health, and other medications.

Absolute Contraindications

• Known hypersensitivity to verapamil or any component of the tablet.
• Severe hypotension (systolic < 90 mmHg) or cardiogenic shock.
• Second- or third-degree AV block without a functioning pacemaker.
• Sick-sinus syndrome (unless a pacemaker is present).
• Unstable heart failure (e.g., New York Heart Association class IV).

Relative Contraindications

• Moderate liver impairment (dose may need adjustment).
• Severe renal impairment (creatinine clearance < 30 mL/min) - consider lower initial dose.
• Concomitant use of beta-blockers, digoxin, or other agents that slow heart rate (requires careful monitoring).
• Pregnancy (category C) and lactation - use only if the potential benefit outweighs risk.

Special Populations

• Elderly patients may be more sensitive to blood-pressure-lowering effects; start with the lower 120 mg dose.
• Patients with hepatic dysfunction should have dosage individualized, often beginning at the lower strength.
• Pregnant or breastfeeding individuals should discuss potential risks with their provider; verapamil crosses the placenta and appears in breast milk.

Safety Profile: Side Effects and Interactions

Common Side Effects

• Constipation - reported most frequently; increase dietary fiber and fluids.
• Dizziness or light-headedness - especially after the first few doses; rise slowly from sitting to standing.
• Peripheral edema - mild swelling of the ankles; may improve with dose adjustment.
• Headache - usually transient.

Serious Adverse Events

• Bradycardia (heart rate < 50 bpm) - monitor pulse; seek medical attention if symptomatic.
• Severe hypotension - may cause fainting; emergency care required if systolic < 80 mmHg.
• Heart block - new AV-node impairment requires immediate evaluation.
• Worsening heart failure - monitor for increased shortness of breath or weight gain.

Drug Interactions

• CYP3A4 inhibitors (e.g., clarithromycin, itraconazole, grapefruit juice) can raise verapamil levels → higher risk of toxicity.
• CYP3A4 inducers (e.g., rifampin, carbamazepine) may lower verapamil concentrations → reduced efficacy.
• Beta-blockers and digoxin - additive slowing of heart rate; dose reduction or close ECG monitoring may be needed.
• Other calcium-channel blockers (e.g., diltiazem) - avoid co-administration because of additive cardiovascular depression.

Food and Lifestyle Interactions

• Avoid large amounts of grapefruit while taking Calan SR, as it can increase drug exposure.
• Alcohol may enhance blood-pressure-lowering effects; consume moderately and monitor for dizziness.
• Driving and operating machinery - be cautious until you know how the medication affects you, especially during dose initiation.

How to Take Calan SR

• Standard dosing: Typically 120 mg or 240 mg taken once daily, preferably with a meal to enhance absorption and reduce gastrointestinal upset.
• Swallow the tablet whole; do not crush, chew, or split, as this destroys the sustained-release matrix.
• Missed dose: If you remember within 12 hours, take it as soon as possible. If it is later, skip the missed tablet and resume the regular schedule-do not double-dose.
• Overdose signs: Severe dizziness, fainting, bradycardia, low blood pressure, or cardiac arrhythmias. Seek emergency medical care; treatment is mainly supportive, with possible use of calcium gluconate as an antidote under professional supervision.
• Discontinuation: Do not stop abruptly if you have been using Calan SR for chronic angina or arrhythmia control. Your provider may taper the dose to avoid rebound hypertension or tachyarrhythmia.

Monitoring and Follow-Up

• Blood pressure and heart rate should be checked within the first week of therapy and after any dose change.
• Electrocardiogram (ECG) is recommended before starting therapy, especially in patients with known conduction abnormalities.
• Renal and hepatic function tests are advised periodically in patients with organ impairment.
• Regular follow-up visits enable dose adjustments and early detection of adverse effects.

Storage and Handling

• Store Calan SR tablets at room temperature (15-30 °C), protected from moisture and direct sunlight.
• Keep the bottle tightly closed and out of reach of children.
• Do not use the medication after the expiration date printed on the label.
• Dispose of unused tablets according to local pharmaceutical waste guidelines or return them to a pharmacy.

Medication-Specific Glossary

Calcium-Channel Blocker

A class of drugs that inhibit the flow of calcium ions through L-type channels, leading to reduced cardiac contractility, slowed conduction, and vasodilation.

AV Node

The atrioventricular node, a key electrical relay that regulates the timing of impulses from the atria to the ventricles.

Sustained-Release (SR) Formulation

A tablet designed to release its active ingredient gradually over an extended period, providing stable plasma concentrations and once-daily dosing.

Bradycardia

An abnormally slow heart rate, typically defined as fewer than 60 beats per minute in adults.

CYP3A4

A liver enzyme responsible for metabolizing many medications; inhibitors increase drug levels, while inducers decrease them.

Medical Disclaimer

This article provides educational information about Calan SR and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.