Some medications change how sildenafil and tadalafil behave in your body, and every medication has possible side effects. This page lists what to tell your provider about and what to watch for. It is provided for reference — your licensed provider makes every prescribing decision.
Medications that can strengthen the effect (CYP3A4 inhibitors)
These can slow the breakdown of sildenafil and tadalafil, making their effect stronger and longer. If you take any of these, your provider may start you at a lower dose. Tell your provider about anything on this list.
Strong inhibitors
- Adagrasib
- Atazanavir
- Ceritinib
- Clarithromycin
- Cobicistat and cobicistat-containing co-formulations
- Darunavir
- Idelalisib
- Itraconazole
- Ketoconazole
- Levoketoconazole
- Lonafarnib
- Lopinavir
- Mifepristone
- Nefazodone
- Nelfinavir
- Nirmatrelvir-ritonavir
- Ombitasvir-paritaprevir
- Ombitasvir-paritaprevir-ritonavir plus dasabuvir
- Posaconazole
- Relacorilant
- Ritonavir and ritonavir-containing co-formulations — found in Kaletra and Norvir (HIV), Paxlovid (COVID-19), and Viekira (chronic hepatitis C)
- Tucatinib
- Voriconazole
Moderate inhibitors
- Amiodarone
- Aprepitant
- Avacopan
- Berotralstat
- Cimetidine
- Conivaptan
- Crizotinib
- Cyclosporine
- Diltiazem
- Duvelisib
- Dronedarone
- Erythromycin
- Fedratinib
- Fluconazole
- Fosamprenavir
- Fosnetupitant-palonosetron
- Grapefruit juice
- Imatinib
- Isavuconazole (isavuconazonium sulfate)
- Lefamulin
- Letermovir
- Netupitant
- Nilotinib
- Nirogacestat
- Ribociclib
- Rilzabrutinib
- Schisandra
- Verapamil
Medications that can weaken the effect (CYP3A4 inducers)
These can speed up the breakdown of sildenafil and tadalafil, which may make them less effective. Your provider may adjust your starting dose. Tell your provider about anything on this list.
Strong inducers
- Apalutamide
- Carbamazepine
- Encorafenib
- Enzalutamide
- Fosphenytoin
- Lumacaftor
- Lumacaftor-ivacaftor
- Mitotane
- Phenytoin
- Rifampin (rifampicin)
Moderate inducers
- Bexarotene
- Bosentan
- Cenobamate
- Dabrafenib
- Dexamethasone
- Dipyrone
- Efavirenz
- Elagolix, estradiol, and norethindrone therapy pack
- Eslicarbazepine
- Etravirine
- Fexinidazole
- Lorlatinib
- Mitapivat
- Modafinil
- Nafcillin
- Pacritinib
- Pexidartinib
- Phenobarbital
- Primidone
- Repotrectinib
- Rifabutin
- Rifapentine
- Sotorasib
- St. John’s wort
Possible side effects
Side effects of sildenafil and tadalafil may include:
- Headaches
- Sudden hearing loss, usually one-sided, within 24 hours of medication use — typically temporary in about a third of those affected
- Dyspepsia / stomach burning
- Vasodilation / flushing
- Diarrhea
- Rhinitis / nasal congestion
- Epistaxis / nosebleeds
- A blue tinge to the vision lasting 2–3 hours and resolving on its own (can be associated with sildenafil)
- In men over 50 with high blood pressure or high cholesterol: a very rare risk of Non-arteritic Anterior Ischemic Optic Neuropathy (NAION) — about 2–4 cases per 10,000 person-years
- Serious retinal detachment
- Retinal vein occlusion
If visual symptoms develop Stop the medication and get evaluated promptly by an eye specialist. For any concerning side effect, discontinue use and consult your personal healthcare provider.