Drug Interactions between interferon alfa-2b and thalidomide

MONITOR: Thalidomide can cause peripheral neuropathy, and concurrent use of other agents that are also associated with this adverse effect can potentiate the risk and/or severity of nerve damage. Peripheral neuropathy is a common, potentially severe side effect of thalidomide that may be irreversible. The condition generally occurs following chronic use over a period of months, although there have also been reported cases following relatively short-term use. The median time to first neuropathy event was 42.3 weeks in one phase 3 study. Occasionally, symptoms may occur some time after thalidomide treatment has been discontinued. The incidence of neuropathy requiring thalidomide discontinuation, dosage reduction, or interruption increases with cumulative dose and duration of therapy.

MANAGEMENT: Caution is advised if thalidomide is used in combination with other neurotoxic agents. All patients treated with thalidomide should be examined at monthly intervals for the first three months of therapy and periodically thereafter to detect early signs of neuropathy such as burning, tingling, pain, or numbness in the hands and feet. Electrophysiological testing may be performed at baseline and every six months during therapy to detect asymptomatic neuropathy. Consideration should be given to immediate discontinuation of thalidomide in patients who develop peripheral neuropathy to limit further damage. Symptoms may improve or return to baseline in some patients upon discontinuation of thalidomide, although the complete time course of this toxicity has not been fully characterized. If necessary, therapy should generally be reinstituted only after neuropathy returns to baseline status. A dosage reduction of thalidomide may be required as clinically indicated.