Effect of folate on phenytoin hyperplasia

There have been some reports that folic acid inhibits phenytoin-induced gingival hyperplasia. The purpose of this double-blind study was to quantify clinically the effects of both systemic and topical administration of folic acid on phenytoin-induced gingival overgrowth in man. For a period of 6 months, one group of phenytoin patients received 2 daily topical applications of a folate solution. An additional group received 2 daily doses of systemic folate while a control group received placebo medication. Results indicate that throughout the 180-day period of the study, the topical folate significantly inhibited gingival hyperplasia to a greater extent than either systemic folate or placebo groups.