India’s Drug Regulator Flags New Safety Risks In Doxycycline, Carbimazole

India’s top drug regulator has ordered updated safety warnings for two commonly prescribed medicines — the antibiotic doxycycline and the anti-thyroid drug carbimazole — following fresh evidence on previously under-recognised adverse drug reactions (ADRs).

The directive has been issued by the Central Drugs Standard Control Organisation (CDSCO), asking State and Union Territory drug regulators to ensure that manufacturers revise prescribing information leaflets (PILs) and promotional literature for both medicines. The move aims to keep the users of these drugs aware of the side effects of these medicines.

Doxycycline, widely used to treat bacterial infections is commonly prescribed for respiratory infections, acne, sexually transmitted infections, urinary tract infection and numerous vector-borne diseases. It will now carry additional warnings about central nervous system (CNS) side effects. These include restlessness, anxiety, irritability, nervousness and dizziness.

Regulators have directed that these reactions be clearly mentioned not only under adverse reactions but also highlighted in the caution section of the package insert.

Carbimazole, prescribed for thyroid disorders such as hyperthyroidism, will be required to include agranulocytosis as a listed adverse drug reaction. Agranulocytosis is a rare but potentially life-threatening condition in which granulocytes — a key type of white blood cell responsible for fighting infections — drop to dangerously low levels. Patients affected by this condition face a significantly increased risk of severe infections and may require urgent medical care.

The safety signals emerged from an assessment of ADR reports conducted by the National Coordination Centre for Pharmacovigilance Programme of India (NCC-PvPI), which functions under the Indian Pharmacopoeia Commission. The findings were discussed during the 26th Signal Review Panel meeting held on March 24, 2025.

The evaluation was based on Patient Population Incidents–Adverse Drug Reactions (PPIs-ADR) drawn from Individual Case Safety Reports (ICSRs). After reviewing the data, the Pharmacovigilance Programme of India (PvPI) recommended formal inclusion of these side effects in prescribing documents.

The recommendations underwent further scrutiny by expert panels. The Subject Expert Committee (SEC) on antimicrobial and antiparasitic drugs, at its meeting on January 8, 2026, endorsed the addition of CNS-related adverse effects to doxycycline labels. Similarly, the SEC on endocrinology and metabolism reviewed safety data on carbimazole and supported listing agranulocytosis in its prescribing information.

Following acceptance of these expert recommendations, the Drugs Controller General (India), Dr Rajeev Singh Raghuvanshi, formally communicated the directions to State and UT licensing authorities. Manufacturers under their jurisdiction have been instructed to incorporate the revised warnings and report compliance.

According to a Union Health Ministry official, the move is part of ongoing pharmacovigilance efforts aimed at strengthening drug safety monitoring. “Updating prescribing information based on emerging evidence improves awareness among healthcare professionals and patients, enables early recognition of adverse reactions and enhances overall patient safety,” the official said.

The directive underscores the regulator’s emphasis on continuous post-marketing surveillance. While both medicines remain widely used and effective when prescribed appropriately, the updated warnings are intended to ensure that risks are promptly identified and managed, reinforcing safeguards within India’s public health system.