Efficacy of Phenytoin for Nocturnal Muscle Cramps: A Preliminary Study

ABSTRACT

BACKGROUND: Nocturnal muscle cramps are sudden, involuntary, painful muscle contractions that occur in the night and are accompanied by hardening of the muscles. Many symptomatic treatments have been introduced for nocturnal muscle cramps, such as quinine, magnesium, and phenytoin. However, the efficacy and safety of these drugs have not been adequately evaluated. To demonstrate the efficacy and safety of phenytoin treatment for nocturnal muscle cramps, we conducted a retrospective study of 16 patients with nocturnal muscle cramps. METHODS: We reviewed 16 patients (6 men, 10 women) who suffered frequent nocturnal muscle cramps and were treated with phenytoin. The patients' clinical information (age, sex, disease duration, and locations of cramps), treatment dosage, and frequency of cramps were obtained by reviewing their medical records. RESULTS: The patients were aged 63.1+/-14.7 years (mean+/-SD; age range, 30-80 years; median age, 68 years). Twelve and four patients received phenytoin doses of 100 and 200 mg/day, respectively. The median duration of medication was 51 days (range, 14-378 days). Phenytoin treatment was effective in all patients; 13 patients (81.3%) experienced a total remission of their symptoms, and a significant reduction (66.7-85.7%) in the frequency of cramps was found in the remaining 3 patients. No adverse effects were reported by any of the patients. CONCLUSIONS: While this retrospective study was conducted with only a small number of patients, the clinical results suggest that phenytoin is a safe and helpful therapy for the treatment of nocturnal muscle cramps.