Safety of low-dose oral dantrolene sodium on hepatic function

To investigate the incidence of hepatobiliary dysfunction after administration of low-dose dantrolene sodium.

A retrospective survey of medical records.

One secondary and 2 tertiary hospitals.

Patients (N=243; 144 men, 27 children; mean age ± SD, 47.8 ± 19.7y) who were administered dantrolene at a daily dose of 12.5 to 400mg for more than 4 weeks.

Not applicable.

Liver function test (LFT) results, including serum total bilirubin, aspartate transaminase, alanine transaminase, and alkaline phosphatase, were recorded before and at least 1 month after the initial dose of dantrolene. In cases of treatment cessation, the reason was investigated. Significantly elevated LFT levels were defined as ≥ to 2 times the upper limit of the normal range.

Treatment duration was 268.0 ± 428.5 days with a daily dose of 65.2 ± 44.7 mg. At the end of the investigation, 95 patients (39.1%) had been lost to follow-up, and 105 (43.2%) had stopped treatment. The reasons for cessation were improved spasticity (42.9%), no effect of the medication (27.6%), weakness (6.7%), and other medical problems (5.7%). Patients with weaknesses did not have elevated LFT values. A 32-year-old man with head injuries and multiple trauma developed hepatic dysfunction 82 days after the initial dose and 43 days after a dose increment to 400mg/d. Other patients did not experience significant LFT abnormalities.

One case of hepatic dysfunction was recorded in 243 cases after at least 4 weeks of low-dose oral dantrolene administration. Low-dose dantrolene can be used safely with meticulous clinical and laboratory monitoring.