Calan Sr is a brand name for a controlled-release formulation of verapamil used to treat hypertension and certain cardiac conditions. It belongs to the class of calcium-channel blockers that act primarily on vascular smooth muscle and cardiac myocytes to reduce peripheral resistance and myocardial oxygen demand. The active ingredient verapamil binds to l-type calcium channels, inhibiting calcium influx and thereby relaxing blood vessels and slowing heart rate. This pharmacological action leads to decreased systolic and diastolic blood pressure, improved exercise tolerance, and mitigation of angina symptoms. By modulating calcium-mediated contractions in the gastrointestinal smooth muscle it also helps manage certain types of arrhythmias and reduces esophageal spasm. Overall the medication provides sustained control of cardiovascular parameters through its extended-release delivery and targeted inhibition of calcium pathways.

Calan Sr is a sustained-release formulation of the calcium channel blocker verapamil used to manage hypertension and certain cardiac arrhythmias. It belongs to the class of non-dihydropyridine calcium channel blockers that inhibit l-type voltage-gated calcium channels in vascular and cardiac smooth muscle. By reducing calcium influx, the drug promotes vasodilation of peripheral arteries and lowers systemic vascular resistance. This vasodilatory effect decreases blood pressure while also slowing conduction through the atrioventricular node, which helps control supraventricular tachycardia. The sustained-release design maintains steady plasma concentrations over 24 hours, allowing once-daily dosing without peaks and troughs. The medication's activity is mediated through reversible blockade of calcium channels, which modifies intracellular signaling pathways that regulate vascular tone. Clinically, the drug improves exercise tolerance and reduces the frequency of angina episodes in patients with chronic stable angina. Its pharmacological profile is characterized by a long half-life, high hepatic metabolism, and minimal renal excretion, contributing to consistent therapeutic effects.

Calan Sr may cause dizziness or lightheadedness in some patients. It can lead to swelling of the ankles or feet due to fluid retention. Headache is another commonly reported symptom. Some individuals experience constipation or changes in bowel habits. Fatigue or a general feeling of weakness may occur. Visual disturbances such as blurred vision have been noted in rare cases. Elevated blood pressure or irregular heart rhythms are possible serious side effects.

Calan Sr may cause constipation in some patients. Headache is another commonly reported symptom. Dizziness or light-headedness may occur especially after standing up quickly. Swelling of the ankles or lower legs has been observed in clinical trials. Fatigue and unusual tiredness are frequently mentioned by users. Occasional slow heart rate or bradycardia has been documented. Rarely, liver enzyme elevation may be detected in blood tests. These effects are generally mild to moderate and often improve with continued use.