Zofran (Ondasetron)

Zofran (ondansetron) is an antiemetic medication used to prevent nausea and vomiting, particularly in the field of anesthesia. It is a selective 5-HT3 receptor antagonist, which works by blocking the action of serotonin in the brain and the gastrointestinal tract.

Route of administration

Oral: Disintegrating tablets, film-coated tablets, and oral solution
Intravenous: Injection
Intramuscular: Injection

Dose

For anesthesia-related nausea and vomiting:

Adult:

 * Oral: 16 mg before anesthesia induction
 * Intravenous: 4 mg before anesthesia induction or immediately before/during/after surgery

Pediatric:

 * Oral: 4 mg for children aged 4-11 years, 30-60 minutes before surgery
 * Intravenous: 0.1 mg/kg (up to 4 mg) for children aged 1 month-12 years, immediately before/during/after surgery

Half-life

The elimination half-life of ondansetron is approximately 3-6 hours.

Expected time to work

Oral: Onset of action is approximately 30 minutes to 2 hours.
Intravenous: Onset of action is approximately 5-30 minutes.

Use in anesthesia

Zofran is commonly used in anesthesia to:

Prevent postoperative nausea and vomiting (PONV)
Prevent nausea and vomiting induced by chemotherapy
Prevent nausea and vomiting associated with radiation therapy

Side effects

Headache
Fatigue
Constipation
Diarrhea
Dizziness

Contraindications

Hypersensitivity to ondansetron or any component of the formulation
Concomitant use with apomorphine
Patients with congenital long QT syndrome

Drug interactions

Serotonin syndrome risk may increase when combined with other serotonergic agents (e.g., SSRIs, SNRIs, TCAs, MAOIs, triptans)