Vitamin deficient is most commonly seen in a pregnant mother who is on phenytoin therapy for epilepsy?
Vitamin B6
Vitamin B12
Vitamin A
Folic acid
Phenytoin interferes with metabolism of folate and patients taking phenytoin may become deficient in folic acid. Phenytoin decreases absorption of folic acid and increases its excretion. Ref: Advanced Therapy in Epilepsy By Wheless, James W. Wheless, James Willmore, Roger A. Brumback, 2009, Page 259.