Antimicrobials · NEET PG Preparation Pharmacology
A 32-year-old male is diagnosed with pulmonary tuberculosis and is started on a standard four-drug regimen including isoniazid, rifampin, pyrazinamid…
Practice question from Antimicrobials (NEET PG Preparation Pharmacology), with the correct answer and a step-by-step solution.
medium · MCQ · Q-B456FB
A 32-year-old male is diagnosed with pulmonary tuberculosis and is started on a standard four-drug regimen including isoniazid, rifampin, pyrazinamide, and ethambutol. Two weeks later, he complains of tingling and numbness in his hands and feet. Which of the following mechanisms best explains this adverse effect?
- A.Competitive inhibition of folate synthesis in bacterial cell walls
- B.Inhibition of mycolic acid synthesis by forming a complex with pyridoxine phosphokinase
- C.Chelation of divalent cations leading to peripheral nerve demyelination
- D.Direct antagonism of vitamin B6 by increasing its renal excretion and inhibiting pyridoxal kinaseCorrect answer
Solution
Isoniazid (INH) structural similarity to pyridoxine (vitamin B6) leads to competitive inhibition of pyridoxal kinase, promoting the urinary excretion of pyridoxine and causing peripheral neuropathy. Pyridoxine supplementation is co-prescribed to prevent this complication.
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