Nitrendipine-induced gingival hyperplasia. First case report. Drug-induced gingival hyperplasia is well documented within the literature. It has been associated with phenytoin, cyclosporine, and calcium channel blocking agents. Nitrendipine is an experimental calcium channel blocking agent that also appears to cause the side effect of drug-induced gingival hyperplasia. The clinical and histologic presentation of this side effect and possible biochemical mechanisms of pathogenesis are discussed. 