Rifapentine and Tadalafil interaction
Rifapentine and Tadalafil: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Rifapentine (Priftin) label · effective 2026-02-06
…Contraceptives/Progestins Ethinyl estradiol, levonorgestrel Immunosuppressants Cyclosporine, tacrolimus Methylxanthines Theophylline Narcotic analgesics Methadone Phosphodiesterase-5 (PDE-5) Inhibitors Sildenafil Thyroid preparations Levothyroxine Tricyclic antidepressants Amitriptyline, nortriptyline 7.5 Other Interactions The conversion of PRIFTIN to 25-desacetyl…
From the Tadalafil (Cialis) label · effective 2026-06-03
CYP3A4 inhibitors (e.g. ketoconazole, ritonavir) increase CIALIS exposure ( 2.7 , 5.10 , 7.2 ) requiring dose adjustment: CIALIS for use as needed: no more than 10 mg every 72 hours CIALIS for once daily use: dose not to exceed 2.5 mg CYP3A4 inducers (e.g. rifampin) decrease CIALIS exposure ( 7.2 ).
Cytochrome P450 Inducers — Studies have shown that drugs that induce CYP3A4 can decrease tadalafil exposure.
CYP3A4 (e.g., Rifampin) — Rifampin (600 mg daily), a CYP3A4 inducer, reduced tadalafil 10-mg single-dose exposure (AUC) by 88% and C max by 46%, relative to the values for tadalafil 10 mg alone.
Although specific interactions have not been studied, other CYP3A4 inducers, such as carbamazepine, phenytoin, and phenobarbital, would likely decrease tadalafil exposure.
The reduced exposure of tadalafil with the coadministration of rifampin or other CYP3A4 inducers can be anticipated to decrease the efficacy of CIALIS for once daily use; the magnitude of decreased efficacy is unknown.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
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.