Drug-induced fever is an elevation in body temperature in the days or weeks following the usage of a new medication. Medications commonly known to cause fever include antimicrobials, anticonvulsants, antibiotics, sympathomimetics, and sulfonamides. Familial predisposition to drug hypersensitivity has been observed, particularly in the setting of renal dysfunction or if the patient is also on thiazide diuretics.

Common drugs that induce fever, by mechanism:

• Hypersensitivity – anticonvulsants, penicillin, minocycline, sulfonamide, allopurinol
• Altered thermoregulatory mechanisms – thyroxine, anticholinergics, amphetamines, cocaine
• Directly related to administration – paraldehyde, pentazocine, amphotericin B, bleomycin
• Direct extension of pharmacologic action – chemotherapy
• Idiosyncratic – succinylcholine, haloperidol, serotonergic

It may not be possible to quickly rule out systemic illness or infection, but discontinuing the suspected medication may eliminate the fever within 72-96 hours. Care should be taken not to put the patient at risk of greater harm by stopping multiple medications at once.

Risk of drug-induced fever increases with the number of medications taken, particularly in older adults and in those with active HIV infection. Patients with cystic fibrosis have a high incidence of drug-induced fever, most commonly from parenteral beta-lactams, piperacillin, and imipenem / cilastatin.