January 15th, 2008

Interaction between midazolam and clarithromycin in the elderly.

The cytochrome P450 3A enzymes (CYP3A4 and CYP3A5) participate in the biotransformation of approximately half of the drugs that undergo metabolic clearance in human adults. CYP3A4 is highly expressed in the liver and the epithelium of the small intestine and represents on average 30% of total hepatic CYP protein and 33–87% of intestinal CYP. CYP3A5 [...]

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January 15th, 2008

Time-dependent inhibition of human drug metabolizing cytochromes P450 by tricyclic antidepressants

Despite many decades of clinical utilization, the drug interaction potential of tricyclic antidepressants (TCAs), particularity inhibition of drugs eliminated by cytochromes P450 (CYP), is not completely understood. Desipramine is known to cause modest increases in the plasma concentrations of paroxetine and nefazodone whereas imipramine and nortriptyline may precipitate phenytoin toxicity. Amitriptyline increases the metabolic [...]

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