Hydroxyurea as a cause of drug fever.

We report on a patient with essential thrombocythemia treated with hydroxyurea who became febrile 3 weeks after the treatment was started. After drug withdrawal, the fever resolved but after rechallenge there was recurrence of the fever. Although hydroxyurea-induced fever is rare, this drug must be added to the list of drugs that produce fever and the physicians should be aware of this possibility.