Azole Antifungal Agents/Hydantoins
This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Medical warning:
Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When taking these two medicines together, your body may not process either medicine properly.
What might happen:
The blood levels of your seizure medicine may increase and cause toxic effects. The blood levels of your antifungal medicine may decrease and reduce the beneficial effects in treating your infection.
What you should do about this interaction:
Contact your doctor if you experience unusual eye movements, unsteadiness, nausea, dizziness, confusion, tremor, slurred speech, drowsiness, or loss of consciousness. Let your doctor know if your infection does not seem to be improving.If your doctor prescribes these medicines together, you may need to have blood levels of these medicines checked. Your doctor may want to adjust the dosage of your medicines.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
References:
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2.Mitchell AS, Holland JT. Fluconazole and phenytoin: a predictable interaction. BMJ 1989 May 13;298(6683):1315.
3.Lazar JD, Wilner KD. Drug interactions with fluconazole. Rev Infect Dis 1990 Mar-Apr;12 Suppl 3:S327-33.
4.Blum RA, Wilton JH, Hilligoss DM, Gardner MJ, Henry EB, Harrison NJ, Schentag JJ. Effect of fluconazole on the disposition of phenytoin. Clin Pharmacol Ther 1991 Apr;49(4):420-5.
5.Touchette MA, Chandrasekar PH, Milad MA, Edwards DJ. Contrasting effects of fluconazole and ketoconazole on phenytoin and testosterone disposition in man. Br J Clin Pharmacol 1992 Jul;34(1):75-8.
6.Ducharme MP, Slaughter RL, Warbasse LH, Chandrasekar PH, Van de Velde V, Mannens G, Edwards DJ. Itraconazole and hydroxyitraconazole serum concentrations are reduced more than tenfold by phenytoin. Clin Pharmacol Ther 1995 Dec;58(6):617-24.
7.Howitt KM, Oziemski MA. Phenytoin toxicity induced by fluconazole. Med J Aust 1989 Nov 20;151(10):603-4.
8.Vfend (voriconazole) US prescribing information. Pfizer Inc. November, 2011.
