Adult
PO
Nausea and vomiting associated w/ cancer chemotherapy: 24 mg as a single dose, 30 min prior to the start of single-day chemotherapy.
Prevent delayed emesis following chemotherapy: 8 mg bid for up to 5 days after the end of a chemotherapy course.
Prophylaxis of chemotherapy-induced nausea and vomiting, moderate emetogenic cancer chemotherapy. Initial: 8 mg 30 min prior to chemotherapy; repeat dose 8 hr after the initial dose, then 8 mg 12 hrly for 1-2 days after completion of chemotherapy.
Highly emetogenic cancer chemotherapy: 24 mg as a single dose 30 min prior chemotherapy.
Prophylaxis of post-op nausea and vomiting 16 mg 1 hr prior to anesth; or 8 mg 1 hr prior to anesth followed by 2 more doses of 8 mg at 8 hrly.
Nausea and vomiting associated with cancer chemotherapy or radiotherapy, less emetogenic chemotherapy and/or radiotherapy: 8 mg 2 hr prior to treatment followed by 8 mg 8-12 hr later.
Prophylaxis of nausea and vomiting associated with radiation therapy. Usual dose: 8 mg tid; undergoing total body irradiation: 8 mg 1-2 hr prior to each fraction of therapy daily.
Undergoing single high-dose fraction radiation therapy to the abdomen: 8 mg 1-2 hr prior to radiation, repeat dose 8 hrly for 1-2 days after completion of therapy. Undergoing daily fractioned radiation to the abdomen: 8 mg 1-2 hr prior to radiation, then 8 hrly; repeat therapy daily.

IV/IM
Nausea and vomiting associated w/ cancer chemotherapy, highly emetogenic chemotherapy: 8 mg as a single dose IM or slow IV inj immediately prior to treatment; or 8 mg IM or slow IV inj given immediately prior to treatment followed by either continuous IV infusion of 1 mg/hr for up to 24 hr or by a further 2 doses of 8 mg 2-4 hr apart; or 32 mg as a single dose via IV infusion over ≥15 min immediately prior to treatment; or 150 mcg/kg IV infusion over 15 min (beginning 30 min prior to chemotherapy) and repeated 4 and 8 hr after the 1st dose. Antiemetic efficacy can be enhanced by giving dexamethasone sodium phosphate 20 mg IV prior to chemotherapy.
Prophylaxis of chemotherapy-induced nausea and vomiting. Initial: 0.15 mg/kg (up to max 16 mg/dose) given as 15-min IV infusion 30 min prior to chemotherapy; repeat twice at 4 hrly after initial dose.
Treatment and prophylaxis of post-op nausea and vomiting: 4 mg as a single dose via IM or 4-8 mg slow IV inj at induction of anesthesia.

Rectal
Nausea and vomiting associated w/ cancer chemotherapy - supp: 16 mg 1-2 hr prior to treatment.
Prevent delayed emesis following chemotherapy - supp: 16 mg once daily for up to 5 days after the end of chemotherapy course.

Adverse drug reactions: headache, hiccups, flushing or warmth sensation, constipation, rash, urticaria; seizures and movement disorders including extrapyramidal symptoms, injection site reaction, dizziness, transient visual disturbances.

Adapted from CIMS Drug Information System. Internet. Accessed on January 10, 2016.