How does nitrofurantoin and tetracycline cause frolic acid deficiency?

How does nitrofurantoin and tetracycline cause frolic acid deficiency?

Most likely alters the absorption of folate.

Nitrofurantoin is a hydantoin derivative. Hydantoin derivatives like phenytoin are thought to cause folate deficiency by inducing microsomal enzymes and increased metabolism of folate. Tetracyclines interfere with the absorption fo folate, and lead to folate deficiency. As a result, both can lead to megaloblastic anemia.

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