Oral dantrolene sodium for tonsillectomy pain: a double-blind study.

Tonsillectomy in adults and older children is typically accompanied by 7 to 14 days of pain. On the basis of clinical observations of patients treated perioperatively with dantrolene sodium for malignant hyperthermia, we hypothesized that pharyngeal muscle spasms are a major factor in tonsillectomy pain. We entered 113 patients, 11 years of age and older, into a double-blind, placebo-controlled study to evaluate the effectiveness of dantrolene sodium in reduction of tonsillectomy pain. Patients were randomly assigned either dantrolene (1.5 mg/kg per day) or placebo orally four times a day for 5 days postoperatively. On a standardized questionnaire, the patient recorded pain, diet, activity level, analgesics, and side effects, daily for 2 weeks. Also, alkaline phosphatase (alk phos) and serum aspartate aminotransferase (SGOT) levels were determined before the operation and 2 weeks after. Patients who received dantrolene had no significant differences in subjective pain, diet, or activity level scores from those of patients who received placebo. Dantrolene patients did, however, require significantly less analgesic use than placebo patients (p = 0.034, 0.015, and 0.005 for postoperative days 2, 3, and 4, respectively). There was no significant difference in side effects or changes in liver enzyme between the dantrolene and placebo groups. We conclude that dantrolene sodium, given in the dosage noted, is effective in reduction of analgesic requirements after tonsillectomy.