This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Peripheral neuritis due to isoniazid is due to formation of which complex ? 
Select and explain. 
A. Hydrazone complex, B. Isobutane complex, C. Isoazoic complex, D. Hydralazine complex
A: Hydrazone complex
Answer: A: Hydrazone complex 
Explanation: Ans. is 'a' i.e., Hydrazone complex Isoniazid reacts with pyridoxal to form a hydrazone, and thus inhibits gneration of pyridoxal phosphate. Isoniazid also combines with pyridoxal phosphate to interfere with its coenzyme function. Due to formation of hydrazones, the renal excretion of pyridoxine compounds is increased. Thus, isoniazid therapy produces a pyridoxine deficiency state.