Cardizem SR 90 mg

Description

Indications
Cardizem SR film-coated tablets are prescribed for the prevention and treatment of chronic stable angina (classical) and vasospastic angina pectoris. It is also utilized either alone or in combination for managing hypertension. Additionally, Cardizem SR has shown efficacy in conditions such as myocardial infarction, coronary artery spasm, arrhythmias, Raynaud’s phenomenon, esophageal motility disorders, and migraine.

The sustained-release formulation of Cardizem SR is specifically indicated for the prevention and management of angina pectoris, including both classical and vasospastic forms. It is also used in the treatment of essential hypertension and for the prophylaxis of selected supraventricular tachyarrhythmias.

Pharmacology Diltiazem hydrochloride, the active ingredient in Cardizem SR, is a calcium channel blocker that exerts both peripheral and coronary vasodilatory effects. It possesses mild negative inotropic properties and inhibits cardiac conduction, particularly at the sinoatrial (SA) and atrioventricular (AV) nodes.

• Antianginal action: Diltiazem directly dilates coronary arteries and arterioles, improving oxygen supply to myocardial tissues. Additionally, its effect on peripheral vasculature reduces systemic resistance and cardiac afterload, thereby lowering myocardial oxygen demand.
• Antiarrhythmic action: By limiting calcium ion influx in cardiac tissue, Diltiazem slows conduction through the SA and AV nodes without impacting accessory pathways or normal atrial conduction.
• Antihypertensive action: Peripheral vasodilation leads to a reduction in vascular resistance, thereby lowering blood pressure.

Diltiazem is rapidly absorbed following oral administration, with peak plasma concentration reached within 30 to 60 minutes. It exhibits high protein binding and undergoes hepatic metabolism, with approximately 60% of the drug excreted through bile.

Dosage & Administration

Film-coated tablet formulation:

• Usual dose: 60 mg three times daily. Dosage may vary based on patient response, and some individuals may require adjustments between 180 mg to 300 mg per day.
• Initiation: A starting dose of 30 mg four times daily may be considered, increasing every 1-2 days until the desired response is achieved. In certain cases, doses up to 480 mg per day have been beneficial, especially in unstable angina.
• Elderly and patients with hepatic/renal impairment: The recommended starting dose is 60 mg twice daily. Heart rate should be monitored, and dosage adjustments should be avoided if the heart rate drops below 50 beats per minute.

Sustained-release formulation:

• Mild to moderate hypertension: Initial dose of 90 mg or 120 mg twice daily (once daily for elderly patients), with a maximum dosage of 360 mg daily (240 mg for elderly patients).
• Angina: Starting dose of 90 mg or 120 mg twice daily, with adjustments as needed. Elderly patients may require a maximum daily dose of 240 mg.

Drug Interactions Diltiazem may be co-administered with short- or long-acting nitrates for angina prophylaxis. However, caution is advised when combining it with other medications that affect cardiac contractility or conduction. Careful dose titration is recommended in such cases.

Contraindications Diltiazem hydrochloride sustained-release tablets are contraindicated in patients with:

• Hypersensitivity to diltiazem or related compounds
• Sick sinus syndrome (unless a functioning pacemaker is present)
• Second- or third-degree AV block (without a pacemaker)
• Severe hypotension
• Acute myocardial infarction with pulmonary congestion confirmed via radiographic imaging

Side Effects
Common adverse effects may include:

• Bradycardia
• Sinoatrial block or atrioventricular block
• Hypotension
• Generalized malaise
• Headache
• Flushing
• Gastrointestinal disturbances (nausea, vomiting, abdominal discomfort)
• Peripheral edema
• Hepatitis (rare)
• Depression (rare)

Pregnancy & Lactation There are no well-controlled studies evaluating the safety of diltiazem in pregnant women. It should only be used during pregnancy if the potential benefits outweigh the risks. Since diltiazem is excreted into breast milk, breastfeeding should be discontinued if treatment is necessary, and an alternative feeding method should be considered.

Therapeutic Class Calcium channel blockers

Storage Conditions Store below 30°C in a dry place, away from direct light and moisture. Keep out of the reach of children.