Venlafaxine pharmacokinetic parameters

Pharmacokinetic parameters of the newer antidepressants are shown in Table 35— 5.9,29 Several antidepressants are not very highly protein bound, and the most notable of these is venlafaxine. The elimination half-lives of nefazodone and... 

Although venlafaxine is a weak inhibitor of CYP2D6, variability has been observed in the pharmacokinetic parameters of venlafaxine in patients with hepatic or renal function impairment. As a precaution, elderly patients taking venlafaxine concurrently with a drug that has a narrow therapeutic index and also is metabolized by CYP2D6 should be carefully monitored. Concurrent use of CYP3A4 inhibitors with venlafaxine has been shown to interfere with its metabolism and clearance. Similar to the other antidepressants that block 5-HT reuptake, venlafaxine may interact pharmacodynamically to cause toxic levels of 5-HT to accumulate, leading to the 5-HT syndrome. 

W.J., and Chiang, S.T. (1992) Introduction of a composite parameter to the pharmacokinetics of venlafaxine and its active O-desmethyl metabolite. / Clin Pharmacol 32 716-724. 

---