Abstrakt

A single-blind n-of-1 study evaluating 4 different doses of phenytoin in a topical analgesic cream for the treatment of peripheral neuropathic pain.

David J. Kopsky and Jan M. Keppel Hesselink

A topical formulation containing phenytoin has been evaluated in a single-blind N-of-1 study in a patient suffering from pain due to small fiber neuropathy. In this placebo controlled study, we evaluated the safety and efficacy of 4 different concentrations of phenytoin: 5%, 10%, 15% and 20%, compounded in a neutral cream. Subsequently, an open re-test phase followed. In both phases of the study phenytoin 20% cream was preferred by the patient. The phenytoin 20% cream was superior in the duration of analgesic effect compared to the other concentrations and placebo. There were no side effects reported.