Oral isoniazid (INH) interferes with which vitamin?

Oral isoniazid (INH) interferes with which vitamin?

• A. Vitamin C
• B. Vitamin B6
• C. Vitamin D
• D. Vitamin B12

Answer: (B)

Isoniazid interferes with vitamin B6 (pyridoxine). It can form a complex with pyridoxal phosphate and inhibit the enzyme that converts B6 to its active form, reducing available B6 in the body. Vitamin B6 is a crucial cofactor for many enzymatic reactions, including those needed to synthesize neurotransmitters like GABA and to make heme. When B6 is deficient, patients on INH are at risk for peripheral neuropathy and sometimes sideroblastic anemia. To prevent this, clinicians often supplement with pyridoxine during INH therapy. The other vitamins listed are not directly affected by INH in this way.

Isoniazid interferes with vitamin B6 (pyridoxine). It can form a complex with pyridoxal phosphate and inhibit the enzyme that converts B6 to its active form, reducing available B6 in the body. Vitamin B6 is a crucial cofactor for many enzymatic reactions, including those needed to synthesize neurotransmitters like GABA and to make heme. When B6 is deficient, patients on INH are at risk for peripheral neuropathy and sometimes sideroblastic anemia. To prevent this, clinicians often supplement with pyridoxine during INH therapy. The other vitamins listed are not directly affected by INH in this way.