Ketoconazole: indications and contraindications

Ketoconazole is a medicine used to fight fungal infections. Therefore, ketoconazole is an antifungal drug. It belongs to the family of imidazoles, where other medications such as clotrimazole, fluconazole or imidazole are also found.

This medication is active by mouth, although in Europe it is only marketed for fungal infections topically, due to the risk of hepatotoxicity. It has the property of inhibiting the synthesis of corticosteroids at the adrenal level and, at higher doses, inhibits the activity of pathogenic fungi.

Some of the fungi on which ketoconazole is effective They are, among many others:

  • Candida albicans.
  • Aspergillus famigatus.
  • Microsporum gypseum.
  • Malassezia furfur.

As we can see, ketoconazole It is used to treat infections due to Candida albicans, as well as those caused by other fungi that belong to this genus. They are responsible for producing the known candidiasis.

Thus, let's start by seeing the general characteristics of this infection to better understand the effect of ketoconazole, as well as the properties of this medicine.

General characteristics of candidiasis

Candidiasis is a fungal infection or mycosis produced by any of the Candida species. Not only is the fungus produced Candida albicans, which is the best known among the general population.

The location of the most common infection is the vagina. However, it can also affect other parts of the body. It usually occurs when the body's defenses are weakened and are not able to keep the fungi that inhabit these parts of the body under control.

On the other hand, mention that 75% of women suffer this infection at least once in their lives, and 50% of these suffer from it on a recurring basis. It is important to know that it is not a sexually transmitted disease, although it can be spread to the sexual partner, in case the infection is suffered.

Nowadays, we have a very effective therapeutic arsenal to treat the symptoms of this infection, among which it is worth highlighting:

  • Itch.
  • Burning sensation, especially when urinating or having sex.
  • Vaginal rash.
  • Thick, white and odorless vaginal discharge.

How does ketoconazole carry out its effect on the body?

This drug is effective against fungal infections because It is capable of inhibiting fungal cell membrane synthesis. Specifically, ketoconazole inhibits the synthesis of ergosterol, which is an essential substance of the fungal membrane.

To do this, it interacts with an enzyme called 14-α-demethylase. This enzyme is necessary to convert lanosterol to ergosterol. In this way, since ergosterol cannot be synthesized from lanosterol, the fungal membrane cannot be created and the fungus dies.

In addition, as we have commented at the beginning of the article, ketoconazole can also affect the synthesis of corticosteroids. In this sense, it is a medicine that has a very potent activity in inhibiting the synthesis of thromboxane. It is sometimes used orally to treat Cushing's syndrome.

For this reason, too it has been used in order to prevent respiratory distress syndrome in adults, especially in patients who present a high risk.

Also read: Fluconazole: utility and side effects

Contraindications of ketoconazole

When administering this medication, it is very important to consider adverse reactions that can occur, as well as the situations in which its use is contraindicated.

As for contraindications, It is a medicine that requires an acid medium for its dissolution and absorption, so that in patients who have achlorhydria or hypochlorhydria, the antifungal cannot reach the plasma levels required to exert its effect.

Further, it is metabolized by the liver, so that patients who have liver damage, can see their problems aggravated with the use of this antifungal.

Its use also It is contraindicated in pregnant and breastfeeding women. The reason for this is that it falls within the category C of pregnancy risk, as teratogenic effects have been observed in animals in studies. Ketoconazole is excreted in breast milk and can cause nuclear jaundice in the nursing baby.

On the other hand, regarding the most common adverse reactions that this drug can trigger, we can mention:

  • Nausea and vomiting.
  • Hepatotoxicity
  • Libido decrease, due to its effect on the synthesis of hormones.
  • Photophobia.

Discover also: Medicines allowed in pregnancy


Ketoconazole It is a medication widely used to fight fungal infections. Above all, it is used for the treatment of candidiasis, a disease that affects many women and is not a sexually transmitted disease.

When starting treatment with this medicine, we must take into account both possible adverse reactions and contraindicated situations. We recommend that you consult your doctor or pharmacist with any questions you have about it.