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1. Why is it necessary to coadminister vitamin B6 (pyridoxine) with isoniazid?
A. Vitamin B6 requirements are higher in tuberculosis patients.
B. Isoniazid causes decarboxylation of -carboxyl groups in vitamin K“dependent enzymes.
C. Isoniazid interacts with pyridoxal phosphate.
D. Isoniazid causes malabsorption of vitamin B6.
E. Isoniazid causes a conversion of homocysteine to cystathionine.
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C. INH react with pyridoxal phosphate to form inactive B6.
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I could not agree more..Bingo..C
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The answer is C.
Certain medications, including isoniazid used for tuberculosis, L-dopa used for Parkinson's disease, and penicillamine used for scleroderma, promote vitamin B6 (pyridoxine) deficiency by reacting with a carbonyl group on 5-pyridoxal phosphate, which is a cofactor for a host of enzymes involved in amino acid metabolism. Foods that contain vitamin B6 include legumes, nuts, wheat bran, and meat. Vitamin B6 deficiency produces seborrheic dermatitis, glossitis, stomatitis, and cheliosis (also seen in other vitamin B deficiencies). A microcytic, hypochromic anemia may result from the fact that the first enzyme in heme synthesis (aminolevulonic synthetase) requires pyridoxal phosphate as a cofactor. However, vitamin B6 is also necessary for the conversion of homocysteine to cystathionine. Consequently, a deficiency of this vitamin could produce an increased risk of cardiovascular disease caused by the resultant hyperhomocystinemia.
