Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other selective 5-HT3 receptor antagonists.
ECG changes including QT interval prolongation has been seen in patients receiving ondansetron. In addition, postmarketing cases of Torsade de Pointes have been reported in patients using ondansetron. Avoid ondansetron 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 development of serotonin syndrome has been reported with 5-HT3 receptor antagonists alone. Most reports have been associated with concomitant use of serotonergic drugs (e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors, mirtazapine, fentanyl, lithium, tramadol, and intravenous methylene blue). Some of the reported cases were fatal. Serotonin syndrome occurring with overdose of ondansetron alone has also been reported. The majority of reports of serotonin syndrome related to 5-HT3 receptor antagonist use occurred in a post-anesthesia care unit or an infusion center.
Symptoms associated with serotonin syndrome may include the following combination of signs and symptoms: mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, with or without gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Patients should be monitored for the emergence of serotonin syndrome, especially with concomitant use of ondansetron and other serotonergic drugs. If symptoms of serotonin syndrome occur, discontinue ondansetron and initiate supportive treatment. Patients should be informed of the increased risk of serotonin syndrome, especially if ondansetron is used concomitantly with other serotonergic drugs (see PRECAUTIONS and OVERDOSAGE).
There is currently no manufacturer warning information available for this drug.
The active ingredient in ondansetron orally disintegrating tablets, USP is ondansetron base, the racemic form of ondansetron, and a selective blocking agent of the serotonin 5-HT3 receptor type. Chemically it is (±) 1, 2, 3, 9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one. It has the following structural formula:
The molecular formula is C18H19N3O representing a molecular weight of 293.4. Ondansetron is a white to off-white powder.
Each 4 mg ondansetron orally disintegrating tablet, USP for oral administration contains 4 mg ondansetron base. Each 8 mg ondansetron orally disintegrating tablet, USP for oral administration contains 8 mg ondansetron base. Each ondansetron orally disintegrating tablet also contains the inactive ingredients mannitol, crospovidone, lactose monohydrate, microcrystalline cellulose, aspartame, strawberry guarana flavor, colloidal silicon dioxide, and magnesium stearate. The strawberry guarana flavor contains maltodextrin, propylene glycol, artificial flavors, and acetic acid. Ondansetron orally disintegrating tablets, USP are orally administered formulation of ondansetron which rapidly disintegrates on the tongue and does not require water to aid dissolution or swallowing.
This product does not meet USP Disintegration Time. The 4 mg and 8 mg tablets disintegrate in approximately 60 seconds.
