Fluconazole
Updated onBenjamin Clanner-Engelshofen is a freelance writer in the medical department. He studied biochemistry and pharmacy in Munich and Cambridge / Boston (USA) and noticed early on that he particularly enjoyed the interface between medicine and science. That is why he went on to study human medicine.
More about the experts All content is checked by medical journalists.Fluconazole belongs to the group of azole antimycotics, so it is an agent against fungal infections. Like other representatives of this group, it is effective against a relatively large number of different types of infectious fungi. If other medications are taken at the same time, it may be necessary to adjust the dose. Here you can read more about the effects and uses of fluconazole, side effects and other interesting facts.
This is how fluconazole works
Fluconazole is an anti-fungal agent (antifungal) from the azole group. It blocks an enzyme that is essential for fungi.
Cholesterol is usually only mentioned in a negative context - as blood fat that can "clog" the blood vessels. In certain amounts, however, cholesterol is essential for the human body. Among other things, it is an important component of the cell membrane. Without cholesterol and thus without a functioning membrane, the body's cells could no longer perform many tasks.
The membrane of fungal cells contains a building block that is structurally related to, but not identical to, cholesterol: ergosterol (also called ergosterol). Without this substance, the fungal membrane loses its stability and the fungus is no longer able to grow.
Azole antifungals such as fluconazole inhibit a specific fungal enzyme (lanosterol-14-alpha-demethylase) that is involved in the production of ergosterol. This selectively slows down the growth of the fungus. Fluconazole inhibits the growth of some fungi (fungistatic) and even kills others (fungicidal).
Uptake, breakdown and excretion
After ingestion by mouth, fluconazole is well absorbed into the blood through the intestinal wall and reaches the highest blood levels after half an hour to one and a half hours. The active ingredient reaches all areas of the body, including the brain, skin and nails.
Only a small part of it is broken down by the body and most of it is excreted unchanged in the urine. About 30 hours after ingestion, the blood level of fluconazole has fallen by half again.
When is fluconazole used?
The active ingredient fluconazole is used to treat fungal infections. Examples of this are the infestation of the oral, nasal and vaginal mucous membranes with yeast Candida albicans (e.g. with oral thrush, vaginal thrush), skin fungal diseases (dermatomycoses) and the infestation of the meninges with Coccidioides immitis (Coccidioidomycosis, also known as valley or desert fever).
Fluconazole therapy can also be used as a precautionary measure to prevent (renewed) fungal infections in immunocompromised patients. These would be, for example, transplant patients, cancer and HIV patients.
The treatment is usually carried out for a limited period of time, as the development of resistance in the fungi cannot be ruled out. In individual cases, however, long-term treatment with fluconazole may also be necessary.
This is how fluconazole is used
Fluconazole is usually given by mouth (orally), for example in the form of capsules. The dosage is determined individually and is between 50 and 400 milligrams daily or 150 milligrams weekly, depending on the indication. In very severe cases, a fluconazole dosage of up to 800 milligrams per day is possible.
A double dose of fluconazole is usually taken on the first day of treatment in order to quickly achieve a high concentration of the active substance in the body.
In some cases, the drug is given directly into a vein (intravenously). Fluconazole is available in juice form for children and people with swallowing problems.
What are the side effects of fluconazole?
One in ten to one hundred people will experience side effects such as headache, abdominal pain, nausea, diarrhea, vomiting, rash and an increase in liver enzymes in the blood.
Anemia, decreased appetite, drowsiness, dizziness, cramps, sensory disturbances, constipation and other digestive disorders, muscle pain, fever, rash and itching are possible in one in hundred to one thousand people.
What should be considered when taking fluconazole?
Contraindications
Fluconazole must not be taken if:
- simultaneous use of terfenadine (antiallergic agent) if the fluconazole daily dose is 400 milligrams or more
- simultaneous intake of drugs that prolong the so-called QT interval in the ECG and are broken down by the enzyme CYP3A4 (e.g. erythromycin, cisapride, astemizole, pimozide and quinidine)
Interactions
The active substance fluconazole inhibits certain drug-breaking enzymes in the liver (namely CYP2C9, CYP2C19 and CYP3A4). If other active ingredients are taken at the same time as fluconazole, their levels can rise sharply due to the reduced breakdown and reach poisonous (toxic) concentrations.
Examples of this are the antiallergic agent terfenadine, pimozide (agent against psychosis), antibiotics such as erythromycin and certain agents against cardiac arrhythmias. Concomitant use must be avoided or requires dose adjustment.
Caution is also advised if ciclosporin, sirolimus or tacrolimus (drugs to prevent transplant rejection) are being taken at the same time. These active ingredients have a narrow therapeutic range (overdosing is easy).
A dose adjustment may also be necessary in combination with other active substances:
- Antidepressants like amitriptyline and nortriptyline
- Anticoagulants such as warfarin and phenprocoumon
- Anti-epilepsy and anti-seizure medicines, such as carbamazepine and phenytoin
- Opioids like methadone, fentanyl, and alfentanil
- Asthma medications such as theophylline
- Lipid lowering drugs such as atorvastatin and simvastatin
- Pain relievers such as celecoxib
- certain cancer medicines, such as olaparib
Age restriction
If indicated, fluconazole can be administered from birth.
pregnancy and breast feeding period
Long-term, high-dose intake of fluconazole during pregnancy can possibly damage the development of the child - even if previous observations speak against an increased risk of malformations. Nevertheless, pregnant women should only take the active ingredient in urgent cases and only for a short time, under medical supervision.
The active ingredient fluconazole is excreted in breast milk. However, if maternal treatment is required, breast-feeding can still be used.
For both pregnancy and breastfeeding, local therapy with clotrimazole, miconazole or nystatin is preferable in the case of vaginal mycosis (vaginal thrush).
How to get medication with fluconazole
In Germany, Austria and Switzerland, drugs with the active ingredient fluconazole are only available on prescription in every dosage form and dosage.
How long has fluconazole been known?
The newer antifungal agents in the azole group were developed from around 1969. A major disadvantage of the first active substances in this group, such as clotrimazole, was that they could only be administered orally and not via injection.
For this reason, ketoconazole was developed in 1978, which can be administered by injection, but is very toxic to the liver. Based on its structure, a new antifungal agent was then developed - it was named fluconazole. It was very effective and well tolerated both orally and via injection. Fluconazole was finally approved in 1990.
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