Pneumonitis, pleural effusion and pericarditis following treatment with dantrolene

A patient developed pulmonary infiltration, pleural effusions and pericarditis three months after starting dantrolene sodium. Peripheral blood eosinophilia and a raised ESR were present. Symptoms and signs resolved after the drug was discontinued. Dantrolene toxicity should be considered in the differential diagnosis of pneumonitis and pleuro-pericarditis.