Folic acid supplementation prevents phenytoin-induced gingival overgrowth in children

Randomized trial in children with epilepsy aged 6-15 years receiving phenytoin monotherapy at a tertiary care teaching hospital. For the folic acid arm, 62 participants were randomized; mean age was 8.7 ± 2.3 years, 37 were boys and 25 were girls, and enrollment occurred about 10 ± 4.3 days after starting phenytoin.

Folic acid 0.5 mg orally once daily for 6 months. The intervention was evaluated in children with epilepsy receiving phenytoin monotherapy.

Folic acid substantially reduced phenytoin-induced gingival overgrowth in children on phenytoin monotherapy. At 6 months, any gingival overgrowth occurred in 13/62 (21.0%) with folic acid versus 51/58 (87.9%) with control; absolute risk reduction was 67% (95% CI 53.8%-80.1%), relative risk reduction was 0.76, and p < 0.001. Severe gingival overgrowth (grade ≥2) was also lower with folic acid: 2/62 (3.23%) versus 8/58 (13.79%) (p = 0.036).

Single-center study in a tertiary hospital with a narrow pediatric epilepsy population on phenytoin monotherapy, which limits generalizability. Follow-up was only 6 months, and the active arm was modest in size (N = 62), so precision for less common outcomes is limited. The study location was not specified in the provided text.