Effect of fluconazole dose on the extent of fluconazole-triazolam interaction.
1. Azole antimycotics interact with the short acting hypnotic triazolam. The effect of fluconazole dose on the extent of fluconazole-triazolam interaction was investigated in a double-blind, randomized cross-over study of four phases. 2. Eight healthy volunteers received either 50 mg, 100 mg or 200 mg (400 mg on day 1) of fluconazole or placebo orally once a day for 4 days. On day 4, they took a 0.25 mg oral dose of triazolam, after which plasma samples were collected and pharmacodynamic effects measured for 18 h. 3. The mean area under the triazolam concentration-time curve (AUC) was increased 1.6-, 2.1- and 4.4-fold (P < 0.001) by fluconazole 50 mg, 100 mg and 200 mg, respectively. The increase in the elimination half-life of triazolam (t1/2,z) varied from 1.3-fold (fluconazole 50 mg, P < 0.05) to 2.3-fold (fluconazole 200 mg, P < 0.001). The peak concentration of triazolam was also increased significantly during all fluconazole phases; more than twofold by fluconazole 200 mg (P < 0.001). 4. The pharmacodynamic effects of triazolam were increased significantly (P < 0.05) by fluconazole 100 mg and 200 mg. 5. Even a small 50 mg daily dose of fluconazole can interact with triazolam and the extent of the interaction increases with increasing fluconazole dose. When triazolam is used concomitantly with fluconazole 50-200 mg, the dose of triazolam should be reduced, accordingly. Simultaneous use of triazolam with higher fluconazole doses should be avoided.
Department of Clinical Pharmacology, University of Helsinki, Finland.
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Varhe
K T
KT
Olkkola
P J
PJ
Neuvonen
D000328:Adult; D000935:Antifungal Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D019540:Area Under Curve; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D015725:Fluconazole / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D006207:Half-Life; D006801:Humans; D008297:Male; D012016:Reference Values; D014229:Triazolam / Q000493:pharmacokinetics / Q000494:pharmacology*
D000935:Antifungal Agents; D014229:Triazolam; D015725:Fluconazole