NEW DELHI: Unexpected side effects from medicines often come to light only after a drug is widely used. To strengthen monitoring of such cases, India’s drug regulator has directed pharmaceutical companies to maintain robust systems for tracking and reporting adverse reactions linked to medicines sold in the market.In a circular issued on June 3, the Central Drugs Standard Control Organisation (CDSCO) reminded drug manufacturers and other stakeholders that they are required to establish and maintain effective pharmacovigilance systems for collecting and reporting adverse drug reactions associated with medicines they manufacture or market.The regulator said the requirement flows from provisions of Schedule M of the Drugs and Cosmetics Rules, which mandate that licence holders maintain systems for collecting, processing and forwarding reports of adverse drug reactions to licensing authorities.Experts said Schedule M lays down Good Manufacturing Practices (GMP) that pharmaceutical companies are required to follow. The latest emphasis on pharmacovigilance reinforces the need for robust post-marketing surveillance, often referred to as Phase IV monitoring, to track the safety of medicines after they reach patients.“Pharmacovigilance helps detect new or previously unrecognised adverse reactions at an early stage, allowing regulators and manufacturers to take timely action,” experts said.While medicines undergo clinical trials before approval, some side effects may only become apparent when they are used by large numbers of patients in real-world settings. Monitoring such reactions helps identify emerging safety concerns and strengthen patient protection.CDSCO said all stakeholders must ensure compliance with provisions under the Drugs and Cosmetics Act and Rules as well as the New Drugs and Clinical Trials Rules, 2019.The regulator also said officials from CDSCO, state licensing authorities and Union Territory administrations may verify compliance during routine inspections and other regulatory activities.The move comes amid growing global emphasis on post-marketing surveillance as regulators increasingly rely on real-world safety data to identify rare or delayed adverse reactions linked to medicines.