Ondansetron and headache

Nursing, Jan 1999 by Shuster, Joel

WHY WAS THIS PATIENT USN MIP DIZZY

A 56-YEAR-OLD WOMAN WITH BREAST cancer was being treated with I.V. doxorubicin and cyclophosphamide. She was nauseated for 3 days after therapy, despite taking prochlorperazine, so the clinical oncologic pharmacist recommended 8 mg of I.V. ondansetron (Zofran), administered 30 minutes before therapy and followed with 8-mg oral doses 4 and 8 hours after therapy.

An hour after the patient took the second oral dose, she became light-headed and complained of a severe headache. She took 1,000 mg of acetaminophen, and when the headache didn't subside in the next hour, she called her health care provider. By this time, she felt hot and recorded her temperature as 101.4 F (38.6 C). She was told to go to the ED. When she arrived at the ED, she was so dizzy that her husband had to help her from the car. Stat blood chemistries and a complete blood cell count were within normal limits. Her vital signs were normal, except for the slight elevation in temperature. She was given I.V. morphine for the severe headache and her dizziness and headache subsided.

What went wrong?

Ondansetron antagonizes serotonin receptors in the peripheral and central nervous systems. Headache is the most common adverse reaction; dizziness is also common. Up to 8% of patients report fever, but having all three reactions is unusual.

What precautions can you take? Alert the patient to possible adverse reactions to ondansetron, such as headache, malaise, dizziness, sedation, diarrhea, constipation, musculoskeletal pain, chills, and fever. Tell her not to drive while she's on the medication because it can make her drowsy. Consider using another antiemetic during chemotherapy. B

Dr. Shuster is clinical associate professor, Temple University, and clinical pharmacist, Allegheny University Hospitals-MCP, both in Philadelphia, Pa. Send examples of adverse drug reactions to: Joel Shuster, PharmD, The Institute for Safe Medication Practices, 300 W. Street Rd., Warminster, PA 18974. Fax: (215) 956-9266. E-mail: shuster@auhs.edu. If we publish your item (anonymously), we'll pay you $25.