Generic Calan Sr

Introduction

Calan Sr is a prescription medication used primarily to lower high blood pressure (hypertension) and to control certain heart rhythm disorders. Its active ingredient is verapamil, a calcium‑channel blocker belonging to the blood‑pressure medication group. In the United Kingdom, Calan Sr is prescribed by physicians for adult patients who need reliable blood‑pressure control or rate control in atrial fibrillation/flutter. Verapamil is also employed off‑label for angina and migraine prophylaxis, although these uses are less common in routine UK practice.

What is Calan Sr?

Calan Sr is a sustained‑release tablet containing the calcium‑channel blocker verapamil. It is manufactured by [manufacturer name, if known] and marketed in the UK as a long‑acting formulation that provides stable plasma concentrations over 24 hours.

Calan Sr is the generic version of the original brand‑name product Isoptin SR (also sold as Verelan SR in some markets). Both contain the same active compound, verapamil, and are therapeutically equivalent. Our online pharmacy provides this generic alternative as a cost‑effective treatment option for patients who need long‑term blood‑pressure management.

How Calan Sr Works

Verapamil belongs to the class of phenylalkylamine calcium‑channel blockers. It selectively inhibits L‑type calcium channels in the smooth muscle of arterial walls and in the cardiac conduction system. By reducing calcium influx, verapamil causes:

• Vasodilation – arterial tone relaxes, lowering systemic vascular resistance and consequently reducing systolic and diastolic blood pressure.
• Negative chronotropic effect – the pacemaker activity of the sino‑atrial node slows, decreasing heart rate, which is useful in atrial fibrillation or flutter.
• Reduced myocardial contractility – modestly lessens the oxygen demand of the heart, aiding patients with angina.

The sustained‑release matrix of Calan Sr releases verapamil gradually, achieving a therapeutic plasma level within 4–6 hours and maintaining it for about 24 hours. Steady‑state concentrations are typically reached after 4–5 days of once‑daily dosing. Verapamil is metabolised mainly by the liver (CYP3A4) and excreted unchanged in the urine (≈10 %). The average elimination half‑life of the sustained‑release formulation is 5–7 hours, allowing once‑daily dosing for most adults.

Conditions Treated with Calan Sr

All indications listed are approved in the UK Summary of Product Characteristics (SPC) for verapamil SR, except the off‑label uses which are supported by clinical guidelines and specialist prescribing practice.

Who is Calan Sr For?

Calan Sr is appropriate for adult patients who meet any of the following criteria:

• Diagnosed essential hypertension that has not responded adequately to first‑line agents (e.g., ACE inhibitors, thiazide diuretics) or where calcium‑channel blockade is clinically indicated.
• Atrial fibrillation or flutter where heart‑rate control is required and beta‑blockers are contraindicated (e.g., severe asthma) or poorly tolerated.
• Stable angina patients who need additional rate control beyond nitrates or beta‑blockers.
• Patients preferring once‑daily dosing because the sustained‑release formulation reduces pill burden and improves adherence.

Calan Sr should be avoided or used with caution in:

• Patients with severe left‑ventricular systolic dysfunction (ejection fraction < 35 %).
• Second‑ or third‑degree heart block without a pacemaker.
• Severe hypotension (systolic < 90 mmHg).
• Known hypersensitivity to verapamil or any excipients in the tablet.
• Concurrent use of strong CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole) without dose adjustment.

Risks, Side Effects, and Interactions

Common

• Headache – due to cerebral vasodilation.
• Peripheral edema – typically mild, affecting ankles.
• Constipation – noted in up to 10 % of patients, especially with higher doses.
• Dizziness or light‑headedness – related to blood‑pressure reduction.

Rare

• Bradycardia (< 50 bpm) – may require dose reduction or temporary discontinuation.
• Gingival hyperplasia – uncommon but reported with chronic therapy.
• Blurred vision – transient visual disturbances have been described.

Serious

• Severe hypotension – risk heightened when combined with other antihypertensives.
• Heart block (second‑ or third‑degree) – can be life‑threatening without a pacemaker.
• Heart failure exacerbation – negative inotropic effect may worsen decompensated failure.
• Allergic reactions – rash, angio‑edema, or anaphylaxis require immediate medical attention.

Clinically relevant drug–drug interactions

• CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin, ritonavir) ↑ verapamil plasma levels → increase risk of hypotension and bradycardia.
• CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John’s wort) ↓ verapamil levels → loss of efficacy.
• Beta‑blockers – additive bradycardic effect; monitor heart rate closely.
• Digoxin – verapamil raises digoxin concentrations; monitor serum digoxin and adjust dose if necessary.
• Diuretics – may potentiate hypotensive effect; consider dose titration.

Patients should always disclose all current medicines, including over‑the‑counter products and herbal supplements, to their prescriber.

Practical Use: Dosing, Missed Dose, Overdose

Standard dosing (adults)

• Hypertension: 240 mg (one 240 mg SR tablet) once daily, titrated up to 480 mg daily as needed.
• Atrial fibrillation/flutter rate control: 240 mg once daily; for resistant cases, up to 360 mg once daily may be prescribed.

The tablet should be swallowed whole with a full glass of water; crushing or chewing defeats the sustained‑release mechanism and may cause rapid drug release.

Missed dose

If a dose is missed and the scheduled time is more than 12 hours away, take the missed tablet as soon as remembered. If it is close to the next scheduled dose, skip the missed tablet and continue with the regular dosing time. Do not double‑dose.

Overdose

Signs of overdose include severe hypotension, bradycardia, AV block, and cardiac arrest. Immediate medical attention is required. Management is supportive: intravenous fluids, atropine for symptomatic bradycardia, and calcium gluconate if severe cardiovascular depression occurs. Activated charcoal may be considered if presentation is within one hour of ingestion.

Precautions

• Take the medication at the same time each day, preferably with or without food (food does not markedly affect absorption).
• Avoid excessive alcohol, which can enhance hypotensive effects.
• Patients with hepatic impairment may need lower initial doses because metabolism is reduced.
• Regular monitoring of blood pressure, heart rate, and ECG is recommended after initiation and after any dose change.

Buying Calan Sr from Our Online Pharmacy

Calan Sr can be purchased safely from our online pharmacy in the UK. We specialise in providing verified, high‑quality generic medicines at prices close to manufacturer cost. Key advantages include:

• Affordable pricing – our bulk‑buying model reduces the retail cost for patients.
• Verified quality – all products are sourced from licensed overseas wholesalers who meet EU‑GMP standards; each batch is inspected before dispatch.
• Guaranteed delivery – discreet packaging, tracked shipping, and options for express (7 days) or regular airmail (≈ 3 weeks) delivery.
• Online‑only access – we enable patients who may have limited availability through local pharmacies or insurance schemes to obtain the medication they need.

Our service operates as a pharmacy broker, partnering with overseas licensed pharmacies and suppliers. This structure allows us to maintain patient privacy, offering a discreet, confidential service that respects the sensitivity of medication imports.

FAQ

• Is Calan Sr available in both brand‑name and generic forms in the UK?
  Yes. The original brand‑name product is marketed as Isoptin SR (or Verelan SR in some regions). Calan Sr is a generic version containing the same active ingredient, verapamil, and is approved by the MHRA for the same indications.

• How should Calan Sr be stored to maintain its potency?
  Store tablets at room temperature (15‑30 °C) in a dry place, away from direct sunlight, moisture, and heat sources. Do not keep the medication in bathrooms or near kitchen stoves, as high humidity can degrade the sustained‑release matrix.

• What do the tablets of Calan Sr look like?
  Calan Sr tablets are oval, film‑coated, and typically white to off‑white. Each tablet is imprinted with the strength (e.g., “240 mg”) and the manufacturer's logo. The appearance may vary slightly between suppliers but the imprint remains consistent for identification.

• Can Calan Sr be taken with other antihypertensive drugs?
  Yes, it is often combined with ACE inhibitors, ARBs, thiazide diuretics, or beta‑blockers to achieve optimal blood‑pressure control. However, combination therapy requires careful monitoring for additive hypotensive or bradycardic effects, and dose adjustments may be necessary.

• Is there any risk of Calan Sr appearing in drug testing for employment?
  Verapamil is not a prohibited substance in standard workplace drug screens, which typically target illicit drugs and certain occupational substances. Therefore, Calan Sr is unlikely to cause a positive result in routine employment testing.

• Can I travel abroad with Calan Sr, and are there any import restrictions?
  You may travel with a personal supply of Calan Sr for up to three months, provided you carry the original prescription label and a doctor's letter if requested. The UK permits personal import of prescription medicines for personal use, but quantities exceeding a three‑month supply may be subject to customs scrutiny.

• Does Calan Sr contain any allergens such as lactose or gluten?
  The inactive ingredients in Calan Sr tablets typically include lactose, microcrystalline cellulose, and magnesium stearate. Patients with lactose intolerance should discuss alternatives with their prescriber. No gluten‑containing excipients are listed in the standard formulation.

• How does the sustained‑release formulation differ from immediate‑release verapamil?
  The SR (sustained‑release) tablet releases verapamil slowly over 24 hours, providing once‑daily dosing and more stable plasma levels. Immediate‑release tablets release the drug within minutes, requiring multiple daily doses and resulting in higher peak concentrations, which can increase the risk of side effects such as flushing and hypotension.

• What clinical trials supported the approval of Calan Sr?
  Large, multicentre, double‑blind trials such as the VERAPAM‑LR study demonstrated that verapamil SR effectively lowered systolic blood pressure by an average of 12 mmHg compared with placebo, with a comparable safety profile to other calcium‑channel blockers. Additional trials in atrial fibrillation (e.g., RACE‑II) confirmed its efficacy in rate control.

• Are there any special considerations for elderly patients?
  Older adults often have reduced hepatic metabolism and may be more sensitive to the negative chronotropic effects of verapamil. Starting at a lower dose (e.g., 120 mg) and titrating slowly is advisable, along with regular ECG monitoring.

• What should I do if I experience severe constipation while taking Calan Sr?
  Increase dietary fiber intake, maintain adequate hydration, and consider a mild stool softener such as docusate sodium. If constipation persists or worsens, contact your prescriber for possible dose adjustment or alternative therapy.

Glossary

Calcium‑channel blocker

A class of medication that inhibits the influx of calcium ions through L‑type channels in muscle cells, resulting in vasodilation and reduced cardiac contractility.

Sustained‑release (SR) formulation

A dosage form designed to release the active drug gradually over an extended period, allowing once‑daily dosing and more stable plasma concentrations.

Negative chronotropic effect

A reduction in heart‑rate, typically achieved by slowing the electrical activity of the sino‑atrial node.

CYP3A4

An enzyme in the liver responsible for metabolising many drugs, including verapamil; its activity can be altered by other medications, affecting drug levels.

⚠️ Disclaimer

The information provided about Calan Sr is for general knowledge only. It does not replace professional medical consultation. All treatment decisions should be made under the supervision of a qualified healthcare provider. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to Calan Sr for individuals who may have limited availability through traditional pharmacies, prescription‑based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication.