Ondansetroninteractions
2 ML ondansetron 2 MG/ML Injection
This is the interactions section of this product’s FDA label — what the manufacturer documented for this drug. It is not a check of your medication list, and a drug missing from it has not been cleared: licensed clinical databases list far more interactions than any single label does. Before combining medicines, ask a pharmacist, who can check everything you take at once and will do it for free.
Named on this label
Every name above is printed in the text below. This is not the full set of drugs that interact with this one — it is the set this manufacturer wrote down.
Drug interactions
7.1 Drugs Affecting
Cytochrome P-450 Enzymes Ondansetron does not appear to induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system of the liver. 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 limited available data, no dosage adjustment is recommended for patients on these drugs.
7.2 Apomorphine
Based on reports of profound hypotension and loss of consciousness when apomorphine was administered with ondansetron, the concomitant use of apomorphine with ondansetron is contraindicated.
7.3 Phenytoin,
Carbamazepine, and Rifampin In patients treated with potent inducers of CYP3A4 (i.e., phenytoin, carbamazepine, and rifampin), the clearance of ondansetron was significantly increased and ondansetron blood concentrations were decreased. However, on the basis of available data, no dosage adjustment for ondansetron is recommended for patients on these drugs.
7.4 Tramadol
Although there are no data on pharmacokinetic drug interactions between ondansetron and tramadol, data from two small trials indicate that concomitant use of ondansetron may result in reduced analgesic activity of tramadol. Patients on concomitant ondansetron self administered tramadol more frequently in these trials, leading to an increased cumulative dose in patient-controlled administration (PCA) of tramadol.
7.5 Serotonergic
Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT 3 receptor antagonists and other serotonergic drugs, including selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs).
7.6 Chemotherapy
In humans, carmustine, etoposide, and cisplatin do not affect the pharmacokinetics of ondansetron. In a crossover trial in 76 pediatric patients, intravenous ondansetron did not increase blood levels of high-dose methotrexate.
7.7 Temazepam
The coadministration of ondansetron had no effect on the pharmacokinetics and pharmacodynamics of temazepam.
7.8 Alfentanil and
Atracurium Ondansetron does not alter the respiratory depressant effects produced by alfentanil or the degree of neuromuscular blockade produced by atracurium. Interactions with general or local anesthetics have not been studied.
Text above is quoted in full from the FDA-approved drug label published by openFDA, effective July 23, 2026. Matched to this product by RxNorm code. Cross-references to other sections of the full prescribing information have been removed, since they point to a document not shown here. Nothing else is changed: no sentence is shortened, reworded or summarised.
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