Fluconazole interactions

Fluconazole is a triazole antifungal that may be administered in recurrent vaginal candidiasis. Fluconazole interacts with sulphonylureas such as glibenclamide, resulting in increased plasma concentrations of the sulphonylurea. 

Sud K, Singh B, Krishna VS, Thennarasu K, Kohli HS, Jha V, Gupta KL, Sakhuja V. Unpredictable cyclosporin-fluconazole interaction in renal transplant recipients. Nephrol Dial Transplant 1999 14(7) 1698-703. 

Fluconazole interacts with a number of drugs, including those metabolised by cytochrome P450 enzymes, but interactions are unlikely to be clinically significant with a single dose of fluconazole. 

Nicolau DP, Qowe HM, Nightingale CH, Quintiliani R. Rifampin-fluconazole interaction in critically ill patients. Ann Pharmaco r (1995) 29,994-6. 

Toxicological studies have demonstrated that there are no important problems with fluconazole. Therapeutic doses of fluconazole may cause enzyme induction in the Hver. This suggests that interactions with other dmgs cannot be excluded. The side effects are similar to those of itraconazole and include nausea, headache, and vertigo. Occasionally, increased Hver enzymes may be noted. Like itraconazole, fluconazole is contraindicated during pregnancy. 

If immunocompromised patients experience frequent or severe recurrences, particularly of esophageal candidiasis, chronic maintenance therapy with fluconazole 100 to 200 mg daily should be considered. In patients with infrequent or mild cases, secondary prophylaxis is not recommended. The rationale for not giving prophylaxis includes availability of effective treatments for acute episodes, risk of developing resistant organisms, potential for drug interactions, and the cost of therapy. 

Itraconazole and ketoconazole (200-800 mg/day orally for 1 year) are effective in 74% to 86% of cases, but relapses are common fluconazole 200-400 mg daily is less effective (64%) than ketoconazole or itraconazole, and relapses are seen in 29% of responders Severe disease Amphotericin B 0.7 mg/kg/day for a minimum total dose of 35 mj kg is effective in 59% to 100% of cases and should be used in patients who require hospitalization or are unable to take itraconazole because of drug interactions, allergies, failure to absorb drug or failure to improve clinically after a minimum of 12 weeks of itiaconazole therapy... 

Black DJ, Kunze KL, Wienkers LC, et al. Warfarin-fluconazole. II.A metabolically based drug interaction in vivo studies. Drug Metab Dispos 1996 24(4) 422-428. 

Drugs that may interact with losartan include cimetidine, phenobarbital, fluconazole, indomethacin, and rifamycins. 

Because trimetrexate is metabolized by a P450 enzyme system, drugs that induce or inhibit this drug metabolizing enzyme system may elicit important drug interactions that may alter trimetrexate plasma concentrations, which include erythromycin, rifampin, rifabutin, ketoconazole, fluconazole, cimetidine, nitrogen substituted imidazole drugs (eg, clotrimazole, ketoconazole, miconazole). 

The importance of these enzymes for drug interactions is that enzyme inducers and inhibitors may preferentially affect certain isoforms and consequently may only affect the metabolism of selected drugs. For example, ketoconazole has the potential to inhibit the metabolism of drugs metabolised to a great extent by the sub-family 3A (e.g. midazolam) but not of those metabolised by sub-family 1A (e.g. theophylline), 2C (e.g. diazepam), or 2D (e.g. metaprolol). In contrast, although fluconazole is a weaker inhibitor of the sub-family 3A than ketoconazole, it also inhibits the sub-family 2C, and so the interactions of fluconazole differ from those of ketoconazole. 

The adverse effects that most frequently result in discontinuation of rifabutin include GI intolerance, rash, and neutropenia. Rifabutin levels will be increased with concurrent administration of fluconazole and clarithromycin, resulting in anterior uveitis, polymyalgia syndrome, and a yellowish-tan discoloration of the skin (pseudojaundice). Other adverse reactions are similar to those of rifampin, such as hepatitis, red-orange discoloration of body fluids, and drug interactions due to effects on the hepatic P450 cytochrome enzyme system. 

Greenblatt, D.J., von Moltke, L.L., Harmatz, J.S., Mertzais, P., Graf, J.A., Durol, A.L., Counihan, M., Roth-Schechter, B., and Shader, R.I. (1998b) Kinetic and dynamic interaction study of zolpidem with ketoconazole, itraconazole, and fluconazole. Clin Pharmacol Ther 64 661-671. 

There are drug products whose interaction with PVC bags and infusion sets are so high that they must include labehng precautions for use with PVC containers. These drugs include antineoplastics such as pachtaxel, docetaxel, tacrolimus, and teniposide, and others such as ciprofloxacin, cefoperazone sodium, fluconazole, metronidazole HC1, cimetidine, and propofol [64,65]. 

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