(for veterinary information only)
BRAND NAME: DIFLUCAN
The development of oral medications to be used in the treatment of invasive fungal infections has represented an immense medical breakthrough. With oral treatment available, human patients no longer require hospitalization several days per week for intravenous treatment of their disease; a more normal and productive lifestyle is now possible. Further, the toxicity profiles of the newer oral drugs represent vast improvement over those of the injectables.
Ketoconazole was the first such oral antifungal drug but it had room for improvement regarding its side effect potential. There were problems with nausea, liver toxicity, and feminization of male patients. Fluconazole was developed in answer to these concerns. Its potential for side effects is far lower and, recently, generic medications have made fluconazole readily affordable. Fluconazole represent yet another generation allowing excellent penetration of the blood/brain barrier, allowing neurologic fungal diseases to be treatable, while in the past they were not.
There are three reasons for choosing fluconazole over other antifungal agents. One reason is to avoid side effects, especially with long term use. Fluconazole is not associated with hormone interference and has less trouble with upset stomach reactions. Another reason to choose fluconazole is ability to penetrate the blood-brain barrier or eye, places where other antifungals cannot go, in order to address a neurologic or ophthalmic infection. Other antifungals are not capable of entering such sequestered areas of the body. The third reason is expense when compared to itraconazole. Itraconazole is frequently the alternative treatment for systemic fungal disease and itraconazole is fraught with bioavailability issues and inconvenient dosing sizes. Fluconazole is available as an effective generic and compounding appropriate pet formulae is not difficult.
Itraconazole is "fungicidal," meaning it kills the fungus, while fluconazole is "fungistatic," which means it prevents the fungus from reproducing. The host's immune system must be strong enough to actually kill the fungus when the patient is on fluconazole.
Fluconazole is typically given twice daily, with our without food. If a dose is accidentally skipped, the next dose should be given when it is remembered and the subsequent dose timed accordingly.
While fluconazole users do not commonly experience side effects, it is important to be aware of what to watch for. Side effects of concern are appetite loss, vomiting, and/or diarrhea. If they occur, medication should be discontinued and liver enzymes should be checked. Despite overall reduced side effects of fluconazole, liver toxicity can occur in as many as one in five patients.
If an adverse side effect occurs, it is expected to resolve with discontinuation of the medication. After recovery, fluconazole can usually be restarted at a lower dose.
IF YOU THINK YOUR PET MAY BE HAVING AN ADVERSE DRUG REACTION,
INTERACTIONS WITH OTHER DRUGS:
The following drugs are stronger in the presence of fluconazole (and thus may have more side effects potential):
Concurrent use with cimetidine, an antacid, will reduce the effect of fluconazole.
Heart rhythm disturbances are possible with fluconazole but generally not significant unless the patient is also using an antibiotic of the macrolide class or cisapride, a motility modifier for the GI tract.
CONCERNS AND CAUTIONS
FUNGAL INFECTIONS AS A GENERAL RULE ARE VERY RESISTANT
Page last updated: 10/4/2020