Seizures associated with high-dose intravenous morphine containing sodium bisulfite preservative.

Abstract

To report a case of seizures occurring during administration of high-dose intravenous morphine containing sodium bisulfite as a preservative. A 56-year-old woman hospitalized with multiple myeloma developed myoclonic and tonic-clonic seizures following administration of intravenous morphine with sodium bisulfite preservative at doses exceeding 400 mg/h. These seizures resolved when the morphine was discontinued, anticonvulsants were administered, and the drug therapy was changed to intravenous fentanyl without preservative. The factors potentially associated with this adverse reaction are discussed and the literature concerning the adverse central nervous system effects of opiates and sulfites is reviewed. High doses of intravenous morphine with sulfite preservative may be associated with seizure development. If patients require high doses of intravenous morphine, a preservative-free formulation should be used to avoid possible additive or synergistic toxicities.