Ondansetron and Rizatriptan interaction
Ondansetron and Rizatriptan: the Ondansetron prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Ondansetron label · effective 2026-04-16
S e ro t o ni n Syndrome: Serotonin syndrome has been reported with 5-HT 3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs.
Patients should be monitored for the emergence of serotonin syndrome, especially with concomitant use of Ondansetron Injection and other serotonergic drugs.
Patients should be informed of the increased risk of serotonin syndrome, especially if Ondansetron Injection is used concomitantly with other serotonergic drugs [see Drug Interactions (7.5 ), Overdosage (10) ] .
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 SSRIs and SNRIs [see Warnings and Precautions (5.3) ] .
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).
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.