Ondansetron: uses, appearance and warnings

Prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin ≥ 50 mg/m 2 . Prevention of nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy. Prevention of nausea and vomiting associated with radiotherapy in patients receiving either total body irradiation, single high-dose fraction to the abdomen, or daily fractions to the abdomen. Prevention of postoperative nausea and/or vomiting. As with other antiemetics, routine prophylaxis is not recommended for patients in whom there is little expectation that nausea and/or vomiting will occur postoperatively. In patients where nausea and/or vomiting must be avoided postoperatively, ondansetron tablets are recommended even where the incidence of postoperative nausea and/or vomiting is low.

Ondansetron tablets USP, 4 mg (ondansetron hydrochloride dihydrate equivalent to 4 mg of ondansetron), are white, oval, film-coated tablets debossed with “4” on one side and “NO” on the other side. They are supplied as follows: NDC 67877-169-30 Bottles of 30 Ondansetron tablets USP, 8 mg (ondansetron hydrochloride dihydrate equivalent to 8 mg of ondansetron), are yellow, oval, film-coated tablets, debossed with “8” on one side and “NO” on the other side. They are supplied as follows: NDC 67877-170-30 Bottles of 30 Store at 20° - 25°C (68° - 77°F) [See USP Controlled Room Temperature]. Dispense in a tight, light-resistant container as defined in the USP.

The concomitant use of apomorphine with ondansetron is contraindicated based on reports of profound hypotension and loss of consciousness when apomorhpine was administered with ondansetron. Ondansetron tablets are contraindicated for patients known to have hypersensitivity to the drug.

Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other selective 5-HT 3 receptor antagonists. ECG changes including QT interval prolongation has been seen in patients receiving ondansetron. In addition, post-marketing cases of Torsade de Pointes have been reported in patients using ondansetron. Avoid ondansetron hydrochloride in patients with congenital long QT syndrome. ECG monitoring is recommended in patients with electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia), congestive heart failure, bradyarrhythmias or patients taking other medicinal products that lead to QT prolongation.

The following have been reported as adverse events in clinical trials of patients treated with ondansetron, the active ingredient of ondansetron tablets. A causal relationship to therapy with ondansetron tablets have been unclear in many cases. Chemotherapy-Induced Nausea and Vomiting The adverse events in Table 5 have been reported in ≥ 5% of adult patients receiving a single 24 mg ondansetron tablet in 2 trials. These patients were receiving concurrent highly emetogenic cisplatin-based chemotherapy regimens (cisplatin dose ≥ 50 mg/m 2 ). Table 5. Principal Adverse Events in US Trials: Single Day Therapy With 24-mg Ondansetron hydrochloride tablets (Highly Emetogenic Chemotherapy) Event Ondansetron 24 mg q.d. n = 300 Ondansetron 8 mg b.i.d. n = 124 Ondansetron 32 mg q.d. …

Ondansetron does not itself appear to induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system of the liver (see CLINICAL PHARMACOLOGY, Pharmacokinetics ). Because ondansetron is metabolized by hepatic cytochrome P-450 drug-metabolizing enzymes (CYP3A4, CYP2D6, CYP1A2), inducers or inhibitors of these enzymes may change the clearance and, hence, the half-life of ondansetron. On the basis of available data, no dosage adjustment is recommended for patients on these drugs. Apomorphine Based on reports of profound hypotension and loss of consciousness when apomorphine was administered with ondansetron, concomitant use of apomorphine with ondansetron is contraindicated (see CONTRAINDICATIONS ). …