Folate treatment of diphenylhydantoin-induced gingival hyperplasia.

It has recently been reported that folic acid supplementation reduced DPH-induced gingival hyperplasia in cat and in a pilot study also in man. The present study was performed to further evaluate this therapy in man. Twenty-three children with DPH-treatment for more than 1 yr, and eight children with short-time DPH-treatment were randomly assigned to groups with and without daily supplementation of folic acid (5 mg Folacin) for 1 yr. Although the DPH-levels were in many cases below the lower reference value, the seizure control of the children was good before and during the year of study. The plasma and red cell folate levels were within or above the given reference values in all but one child. There were no significant changes in the size of the gingival hyperplasias after 1 yr of folate supplementation. Nine severely mentally retarded DPH-treated adults were also given supplementation with folic acid. Their serum DPH-levels were above the higher reference values both at the start and during the study. Their plasma and red cell folic acid levels were below the reference value at the start of the study, but as a consequence of the Folacin supplementation these values rose. The size of the gingival hyperplasias was significantly reduced. Seizure control was unchanged. Folate levels should be checked and supplementation with folic acid considered in patients on long-term anticonvulsive multipharmacy therapy.