Ketoconazole (Nizoral)

Ketoconazole (Nizoral) is an approved anti-fungal drug. It works primarily by inhibiting the synthesis of ergosterol, a main component in the fungal cell membrane. It is related to itraconazole (Sporanox) and fluconazole (Diflucan) and is manufactured by Janssen Pharmaceuticals.

Among people with HIV, it is used to treat candidiasis (thrush) as an alternative to fluconazole and as maintenance therapy to prevent relapses of candidiasis. It is also used to treat blastomycosis and non-meningeal coccidioidomycosis, and to prevent relapses.

Ketoconazole comes as tablets or as a suspension. It requires the stomach to be acid for it to be properly absorbed, so it should not be taken at the same time as antacids or drugs that include an antacid such as ddI (didanosine, Videx) tablets.1 Ketoconazole can be taken at the same time as ddI capsules (VidexEC) because these do not contain an antacid.2 For some people, taking ketoconazole cola helps to increase the stomach acidity and improve the drugs absorption.

Dose-related gastrointestinal side-effects are the commonest problems but these rarely require treatment to be stopped in people taking doses up to 400mg a day. Ketoconazole can also rarely cause clinically important, even fatal, hepatitis. It is therefore important that liver functions are regularly monitored.

Other side-effects may include nausea and vomiting, abdominal pain, loss of appetite, rash, itching, adrenal insufficiency, decreased libido, impotence, breast enlargement, menstrual abnormalities, headache, fever and chills and discomfort in bright light.

Ketoconazole causes an increase in the levels of most protease inhibitors, as it is an inhibitor of the CYP3A4 enzyme.3 4 5 Dose reductions of ketoconazole may be necessary to reduce the risk of side-effects, when it is taken by patients also taking atazanavir (Reyataz), indinavir (Crixivan), lopinavir, ritonavir (Norvir) or tipranavir (Aptivus).

Ketoconazole should not be taken by patients taking nevirapine (Viramune), due to a dramatic reduction in ketoconazole levels.6 A similar reduction in ketoconazole levels is theoretically possible in patients taking efavirenz (Sustiva), but this has not been studied.

Ketoconazole should be taken with caution by patients taking other drugs that are metabolised by the same route.


  1. Knupp CA et al. Pharmacokinetics of didanosine and ketoconazole after coadministration to patients seropositive for the human immunodeficiency virus. J Clin Pharmacol 33: 912-917, 1993
  2. Damle BD et al. Lack of effect of simultaneously administered didanosine encapsulated enteric bead formulation (Videx EC) on oral absorption of indinavir, ketoconazole, or ciprofloxacin. Antimicrob Agents Chemother 46: 385-391, 2002
  3. Khaliq Y et al. Effect of ketoconazole on ritonavir and saquinavir concentrations in plasma and cerebrospinal fluid from patients infected with human immunodeficiency virus. Clin Pharmacol Ther 68: 637-646, 2000
  4. Boffito M et al. Ketoconazole and lopinavir / ritonavir coadministration: boosting beyond boosting. AIDS Res Hum Retroviruses 19: 941-942, 2004
  5. Bertz R et al. Evaluation of the pharmacokinetics of multiple dose ritonavir and ketoconazole in combination. Clin Pharmacol Ther 63: 230, 1998
  6. Lamson M et al. The pharmacokinetic interactions of nevirapine and ketoconazole. Twelfth World AIDS Conference, Geneva, abstract 12218, 1998

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.