What is one of the adverse reactions of antitubercular medication INH?

The correct answer is peripheral neuropathy, which is a well-documented adverse reaction associated with the use of isoniazid (INH), an antitubercular medication. INH can interfere with vitamin B6 (pyridoxine) metabolism, which is essential for nerve health. A deficiency in vitamin B6 can lead to symptoms of peripheral neuropathy, such as tingling, numbness, or pain in the extremities. Patients taking INH are often advised to take vitamin B6 supplements to help prevent this side effect.

Other options, while they may represent potential issues in a clinical context, are not specifically linked to INH. Weight gain is not commonly associated with this medication; instead, patients may experience changes in appetite. Pneumonia is unrelated and not a recognized direct adverse reaction of INH. Anemia may occur in some patients for various reasons, but it is not a direct or common side effect of INH treatment. Understanding these nuances helps in recognizing the importance of monitoring and potentially supplementing vitamin B6 in patients receiving INH therapy.