<p><strong>Metronidazole:</strong>&nbsp;Disulfiram-like reaction with alcohol. Increased oral anticoagulant effect, blood levels of phenytoin, lithium toxicity, plasma cone of astemizole &amp; terfenadine; blood cone of carbamazepine. Decreased blood levels with phenobarb. Risk of CNS-related effects (eg psychotic reactions) with disulfiram. Increased blood levels &amp; neurologic effects with cimetidine. May increase blood levels &amp; toxicity of fluorouracil; toxicity of cyclosporine. Increased cardiotoxicity with amiodarone. Interference with blood levels of liver enzymes, glucose (hexokinase method), theophylline &amp; procainamide. Decreased levels with phenytoin.<br />
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<strong>Miconazole:</strong>&nbsp;Increased risk of bleeding with acenocoumarol, anisindione, dicumarol, phenindione, phenprocoumon, warfarin; plasma cone &amp; exposure to oxybutinin.<br />
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May increase risk of phenytoin, phosphenytoin, cyclosporine, trimetrexate toxicity &amp; cardiotoxicity with pimozide. May inhibit metabolism of astemizole, cisapride &amp; terfenadine. Reduced carbamazepine metabolism. Increased or prolonged effects of opioid (fentanyl). May cause hypoglycemia with glimepiride. Reduced clearance &amp; increased plasma cone of oxycodone. May increase bioavailability of tolterodine (in patients with deficient CYP2D6 activity).</p>