Ketoconazole and Tolvaptan interaction
Ketoconazole 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 Ketoconazole label · effective 2026-07-07
…contraindicated with ketoconazole tablets: methadone, disopyramide, dronedarone, ergot alkaloids such as dihydroergotamine, ergometrine, ergotamine, methylergometrine, irinotecan, lurasidone, oral midazolam, alprazolam, triazolam, felodipine, nisoldipine, ranolazine, tolvaptan, eplerenone, lovastatin, simvastatin and colchicine (see PRECAUTIONS: Drug Interactions ).
Other colchicine, in subjects with renal or hepatic impairment; tolvaptan colchicine alcohol, cinacalcet Colchicine: The potential increase in plasma concentrations of colchicine when coadministered with ketoconazole tablets may increase the risk of potentially fatal adverse events Tolvaptan: Ketoconazole 200 mg administered with tolvaptan increased tolvaptan…
Larger doses would be expected to produce larger increases in tolvaptan exposure.
There is not adequate experience to define the dose adjustment that would be needed to allow safe use of tolvaptan with strong CYP3A inhibitors such as ketoconazole.
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.