Adult metaxalone ingestions reported to Texas poison control centers, 2000-2006

Few data exist on potentially adverse metaxalone (Skelaxin(R)) ingestions in adults. All metaxalone ingestions involving patients aged >= 20 years during 2000-2006 were retrieved from Texas poison control centers. Exclusion criteria were lack of follow-up or multiple substance ingestion. Cases were analyzed for selected demographic and clinical factors. Of the 142 patients, 66.2% were female. Dose ingested was reported for 61 patients. Of those cases with a reported dose, distribution by management site was 29.5% on-site, 59.0% already at/en route to health care facility, and 11.5% referred to health care facility. Final medical outcome was 'no effect' for 50.8% cases, 'minor effect' for 31.1%, and 'moderate effect' for 18.0%. The more common adverse clinical effects reported were drowsiness (27.9%), tachycardia (6.6%), agitation (6.6%), nausea (4.9%), dizziness (4.9%), slurred speech (4.9%), and tremor (4.9%). A moderate medical outcome occurred in 13.6% of ingestions of <= 2400 mg and 20.5% of ingestions of >2400 mg. Management involved a health care facility in 18.2% of ingestions of <= 2400 mg and 100.0% of ingestions of > 2400 mg. This study found that adult ingestions of higher doses of metaxalone, particularly > 2400 mg, were associated with more serious medical outcomes and were managed at health care facilities. This study also proposes triage guidelines for when ingestions can be safely managed at home.