Nirmatrelvir and ritonavir and Tolvaptan interaction
Nirmatrelvir and ritonavir and Tolvaptan: both prescribing labels 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 Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
…hypertension (PAH) • Sedative/hypnotics: triazolam, oral midazolam • Serotonin receptor 1A agonist/serotonin receptor 2A antagonist: flibanserin • Vasopressin receptor antagonists: tolvaptan ➢ Drugs that are strong CYP3A inducers where significantly reduced nirmatrelvir or ritonavir plasma concentrations may be associated with the potential for loss of virologic…
Vasopressin receptor antagonists tolvaptan ↑ tolvaptan Co-administration contraindicated due to potential for dehydration, hypovolemia and hyperkalemia [see Contraindications (4) ] .
From the Tolvaptan (SAMSCA) label · effective 2026-05-07
…dominant polycystic kidney disease (ADPKD) outside of FDA-approved REMS [see Warnings and Precautions (5.2) ] Unable to sense or respond to thirst Hypovolemic hyponatremia Taking strong CYP3A inhibitors [see Warnings and Precautions (5.5) ] Anuria Hypersensitivity (e.g., anaphylactic shock, rash generalized) to tolvaptan or any components of the product [see Adverse…
Concomitant use of strong CYP3A inhibitors ( 4 )
Avoid use with moderate to strong CYP3A inhibitors ( 5.5 )
Do not use SAMSCA with strong inhibitors of CYP3A [see Contraindications (4) ] and avoid concomitant use with moderate CYP3A inhibitors.
Avoid concomitant use with: Moderate CYP3A inhibitors ( 7.1 )
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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.