Azole antifungal (strong CYP3A4 inhibitor)
Ketoconazole: What to Know Before You Take It
Also known as Nizoral
A patient-focused safety profile with information from public regulatory sources.
Reviewed by the OmniRx Health clinical team•Last reviewed Jul 4, 2026
In plain language
What Ketoconazole is used for
INDICATIONS & USAGE Ketoconazole shampoo, 2% is indicated for the treatment of tinea (pityriasis) versicolor caused by or presumed to be caused by Pityrosporum orbiculare (also known as Malassezia furfur or M. orbiculare ) . Note: Tinea (pityriasis) versicolor may give rise to hyperpigmented or hypopigmented patches on the trunk which may extend to the neck, arms and upper thighs. Treatment of the infection may not immediately result in normalization of pigment to the affected sites. Normalization of pigment following successful therapy is variable and may take months, depending on individual skin type and incidental sun exposure. Although tinea versicolor is not contagious, it may recur because the organism that causes the disease is part of the normal skin flora.
Read before you decide
Risks and precautions
Who should not take it
CONTRAINDICATIONS Ketoconazole shampoo, 2% is contraindicated in persons who have known hypersensitivity to the active ingredient or excipients of this formulation.
Medication review
Ketoconazole drug interactions
Ketoconazole + LovastatinConcomitant administration with strong CYP3A4 inhibitors (e.g., itraconazole, ketoconazole, posaconazole, voriconazole, HIV protease inhibitors, boceprevir, telaprevir, erythromycin, clarithromycin, telithromycin, nefazodone and cobicistat-containing products) (see WARNINGS , Myopathy/Rhabdomyolysis ).Contraindicated interactionKetoconazole + Fluticasone Salmeterol• Strong cytochrome P450 3A4 inhibitors (e.g., ritonavir, ketoconazole): Use not recommended.Major interactionKetoconazole + RifampinTelaprevir Decrease AUC by 92% Systemic Hormonal Contraceptives Prevention or Management: Advise patients to change to non-hormonal methods of birth control during rifampin therapy Estrogens Decrease exposure Progestins Anticonvulsants Phenytoin Administered with rifampin 450 mg daily Decrease exposure Antiarrhythmics Disopyramide Decrease exposure Mexiletine Decrease exposure Quinidine Decrease exposure Propafenone Decrease AUC by 50%–67% Tocainide Decrease exposure Antiestrogens Tamoxifen D…Major interactionKetoconazole + Rivaroxaban7.2 Drugs that Inhibit Cytochrome P450 3A Enzymes and Drug Transport Systems Interaction with Combined P-gp and Strong CYP3A Inhibitors Avoid concomitant administration of XARELTO with known combined P-gp and strong CYP3A inhibitors (e.g., ketoconazole and ritonavir) [see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3) ] .Major interactionKetoconazole + Sildenafil7 DRUG INTERACTIONS Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhib…Major interactionKetoconazole + Tamsulosin7 DRUG INTERACTIONS • Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole).Major interactionKetoconazole + TicagrelorAvoid use of strong inhibitors of CYP3A (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir and telithromycin) [see Clinical Pharmacology ( 12.3 )] .Major interactionKetoconazole + AlprazolamExamples Ketoconazole, itraconazole, clarithromycin Moderate or Weak Inhibitors of CYP3A Clinical implication Concomitant use of alprazolam with CYP3A inhibitors may increase the concentrations of alprazolam, resulting in increased risk of adverse reactions of alprazolam [see Clinical Pharmacology (12.3) ].Moderate interactionKetoconazole + Codeineketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of Codeine Sulfate Tablets and CYP3A4 inducers can result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence [see Warnings and Precautions ( 5.7 )] .Moderate interactionKetoconazole + EszopicloneUse with ethanol causes additive psychomotor impairment ( 7.1 ) • Rifampicin Combination use may decrease exposure and effects of eszopiclone tablets ( 7.2 ) • Ketoconazole Combination use increases exposure and effect of eszopiclone tablets.Moderate interactionKetoconazole + Hydrocodone AcetaminophenRisks of Concomitant Use or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of hydrocodone bitartrate and acetaminophen tablets with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of hydrocodone bitartrate and acetaminophen tablets and prolong opioid adverse reactions, and which may cause potentially fatal respirato…Moderate interactionKetoconazole + Oxycodone5.6 Risks of Concomitant Use or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of oxycodone hydrochloride with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of oxycodone and prolong opioid adverse reactions, which may cause potentially fatal respiratory depression [see Warnings and Precautions (5.3)] , particularl…Moderate interactionKetoconazole + PhenytoinTable 1: Drugs That Affect Phenytoin Concentrations Interacting Agent Examples Drugs that may increase phenytoin serum levels Antiepileptic drugs Ethosuximide, felbamate, oxcarbazepine, methsuximide, topiramate Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazol…Moderate interactionKetoconazole + PravastatinCaution should also be exercised if a statin or other agent used to lower cholesterol levels is administered to patients also receiving other drugs (e.g., ketoconazole, spironolactone, cimetidine) that may diminish the levels or activity of steroid hormones.Moderate interactionKetoconazole + TacrolimusStrong CYP3A Inhibitors : Protease inhibitors (e.g., nelfinavir, telaprevir, boceprevir, ritonavir), azole antifungals (e.g., voriconazole, posaconazole, itraconazole, ketoconazole), antibiotics (e.g., clarithromycin, troleandomycin, chloramphenicol), nefazodone, letermovir, Schisandra sphenanthera extracts May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation).Moderate interactionKetoconazole + Tramadolketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of tramadol hydrochloride extended-release tablets and CYP3A4 inducers can decrease the plasma concentration of tramadol [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to tramadol, [see Warnings and Precautions ( 5.Moderate interactionKetoconazole + ZolpidemJohn's wort): Combination use may decrease effect ( 7.2 ) Ketoconazole: Combination use may increase effect ( 7.2 ) 7.1 CNS-Active Drugs CNS Depressants Coadministration of Zolpidem with other CNS depressants increases the risk of CNS depression.Moderate interactionKetoconazole + Apixaban( 7.2 , 12.3 ) 7.1 Combined P-gp Strong CYP3A4 Inhibitors For patients receiving apixaban 5 mg or 10 mg twice daily, the dose of apixaban should be decreased by 50% when coadministered with drugs that are combined P-gp and strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir) [see Dosage and Administration (2.5) and Clinical Pharmacology ( 12.3) ].Minor interactionKetoconazole + AtorvastatinExamples: Erythromycin, clarithromycin, itraconazole, ketoconazole, posaconazole, and voriconazole.Minor interactionKetoconazole + Buprenorphine Naloxoneketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inducers can decrease the plasma concentration of buprenorphine [see Clinical Pharmacology ( 12.3 )] , potentially resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to buprenorphine.Minor interactionKetoconazole + ColchicineDrug Interactions: Pharmacokinetic Parameters for Colchicine Tablets in the Presence of the Coadministered Drug Coadministered Drug Dose of Coadministered Drug (mg) Dose of Colchicine Tablets (mg) N % Change in Colchicine Concentrations from Baseline (Range: Min – Max) C max AUC 0-t Cyclosporine 100 mg single dose 0.6 mg single dose 23 270.0 (62.0 to 606.9) 259.0 (75.8 to 511.9) Clarithromycin 250 mg twice daily, 7 days 0.6 mg single dose 23 227.2 (65.7 to 591.1) 281.5 (88.7 to 851.6) Ketocon…Minor interactionKetoconazole + DabigatranIn patients with moderate renal impairment (CrCl 30 to 50 mL/min), reduce the dosage of dabigatran etexilate to 75 mg twice daily when administered concomitantly with the P-gp inhibitors dronedarone or systemic ketoconazole.Minor interactionKetoconazole + DexamethasoneDrugs which inhibit CYP 3A4 (e.g., ketoconazole, macrolide antibiotics such as erythromycin) have the potential to result in increased plasma concentrations of corticosteroids.Minor interactionKetoconazole + DiazepamAt present, this reaction is known to occur with cimetidine, ketoconazole, fluvoxamine, fluoxetine, and omeprazole.Minor interactionKetoconazole + DigoxinConivaptan 33% 43% Diltiazem 20% NA Indomethacin 40% NA Mirabegron 29% 27% Nefazodone 27% 15% Nifedipine 45% NA Propantheline 24% 24% Quinine NA 33% Rabeprazole 29% 19% Saquinavir 27% 49% Spironolactone 25% NA Telmisartan 20 to 49% NA Tricagrelor 31% 28% Tolvaptan 30% 20% Trimethoprim 22 to 28% NA Digoxin concentrations increased, but magnitude is unclear Alprazolam, azithromycin, cyclosporine, diclofenac, diphenoxylate, epoprostenol, esomeprazole, ibuprofen, ketoconazole, lansoprazole, metfo…Minor interactionKetoconazole + FamotidineSee the prescribing information for other drugs dependent on gastric pH for absorption for administration instructions, including atazanavir, erlotinib, ketoconazole, itraconazole, ledipasvir/sofosbuvir, nilotinib, and rilpivirine.Minor interactionKetoconazole + FluoxetineAdditionally, in vitro studies have shown ketoconazole, a potent inhibitor of CYP3A4 activity, to be at least 100 times more potent than fluoxetine or norfluoxetine as an inhibitor of the metabolism of several substrates for this enzyme, including astemizole, cisapride, and midazolam.Minor interactionKetoconazole + ItraconazoleAlthough many of the clinical drug interactions in Table 1 are based on information with a similar azole antifungal, ketoconazole, these interactions are expected to occur with itraconazole.Minor interactionKetoconazole + LansoprazoleDrugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole) Clinical Impact: Lansoprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity.Minor interactionKetoconazole + MethylprednisoloneDrugs such as troleandomycin and ketoconazole may inhibit the metabolism of methylprednisolone and thus decrease its clearance.Minor interactionKetoconazole + OxybutyninMean oxybutynin chloride plasma concentrations were approximately 2 fold higher when Oxybutynin chloride extended-release tablets were administered with ketoconazole, a potent CYP3A4 inhibitor.Minor interactionKetoconazole + PantoprazoleDrugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole) Clinical Impact: Pantoprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity.Minor interactionKetoconazole + Quetiapine7 DRUG INTERACTIONS Concomitant use of strong CYP3A4 inhibitors: Reduce quetiapine dose to one sixth when coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) ( 2.5 , 7.1 , 12.3 ) Concomitant use of strong CYP3A4 inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7-14 days) of potent CYP3A4 inducers (e.g., phenytoin, rifampin, St.Minor interactionKetoconazole + SimvastatinExamples: Select azole anti-fungals (e.g., itraconazole, ketoconazole, posaconazole, and voriconazole), select macrolide antibiotics (e.g., erythromycin and clarithromycin), select HIV protease inhibitors (e.g., nelfinavir, ritonavir, and darunavir/ritonavir), select HCV protease inhibitors (e.g., boceprevir and telaprevir), cobicistat-containing products, and nefazodone.Minor interactionKetoconazole + SucralfateDrug Interactions Some studies have shown that simultaneous sucralfate administration in healthy volunteers reduced the extent of absorption (bioavailability) of single doses of the following: cimetidine, digoxin, fluoroquinolone antibiotics, ketoconazole, l-thyroxine, phenytoin, quinidine, ranitidine, tetracycline, and theophylline.Minor interactionKetoconazole + Tadalafilketoconazole, ritonavir) increase tadalafil exposure ( 2.7 , 5.10 , 7.2 ) requiring dose adjustment: Tadalafil tablets for use as needed: no more than 10 mg every 72 hours Tadalafil tablets for once daily use: dose not to exceed 2.5 mg CYP3A4 inducers (e.g.Minor interactionKetoconazole + TrazodoneIt is likely that ketoconazole, indinavir, and other CYP3A4 inhibitors such as itraconazole may lead to substantial increases in trazodone plasma concentrations with the potential for adverse effects.Minor interactionKetoconazole + VenlafaxineKetoconazole A pharmacokinetic study with ketoconazole 100 mg b.i.d.Minor interactionKetoconazole + WarfarinTable 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral co…Minor interaction
Check this against your full medication list in the Interaction CheckerFDA safety data
Most-reported side effects
Based on 16,862 FAERS reports. Reports do not prove the drug caused the effect.
drug ineffective 1,729off label use 1,213fatigue 950pruritus 942nausea 861rash 830diarrhoea 788pain 741headache 728psoriasis 649dyspnoea 622dizziness 604
Explore full FDA safety dataRegulatory record
FDA recalls (3)
Class IITerminated · Apr 13, 2022
cGMP deviations: Temperature abuse
Recalling firm: Mckesson Medical-Surgical Inc. Corporate Office
Class IIITerminated · Nov 18, 2013
Failed Impurities/Degradation Specifications: Out-of-Specification degradant results.
Recalling firm: Fougera Pharmaceuticals Inc.
Class IIITerminated · Jul 18, 2012
Failed Impurities/Degradation Specifications: Ketoconazole Cream 2% is the subject of a voluntary drug recall by Fougera due to an Out Of Specification result for an unknown degradant product
Recalling firm: Fougera Pharmaceuticals Inc.
Common questions
Patient questions
What is Ketoconazole prescribed for?
INDICATIONS & USAGE Ketoconazole shampoo, 2% is indicated for the treatment of tinea (pityriasis) versicolor caused by or presumed to be caused by Pityrosporum orbiculare (also known as Malassezia furfur or M. orbiculare ) . Note: Tinea (pityriasis) versicolor may give rise to hyperpigmented or hypopigmented patches on the trunk which may extend to the neck, arms and upper thighs. Treatment of the infection may not immediately result in normalization of pigment to the affected sites. Normalization of pigment following successful therapy is variable and may take months, depending on individual skin type and incidental sun exposure. Although tinea versicolor is not contagious, it may recur because the organism that causes the disease is part of the normal skin flora.
What are the key warnings and safety precautions for Ketoconazole?
Patients taking Ketoconazole should be screened for contraindications, organ function, and concurrent medications by a licensed healthcare provider before beginning treatment.
Does Ketoconazole interact with other medications or foods?
Ketoconazole has 39 documented drug interaction(s) and 0 food interaction(s) in clinical databases. Always provide your complete medication list to your clinician.
This information is educational — not medical advice.
This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.