Where is paxil metabolized

The terminal half-life is about one day, although there is a wide intersubject variability e. In elderly subjects there is wide interindividual variation in steady-state pharmacokinetic parameters, with statistically significantly higher plasma concentrations and slower elimination than in younger subjects, although there is a large degree of overlap in the ranges of corresponding parameters. In severe renal impairment higher plasma levels of paroxetine are achieved than in healthy individuals after single dose.

In moderate hepatic impairment the pharmacokinetics after single doses are similar to those of normal subjects. Paroxetine is not a general inducer or inhibitor of hepatic oxidation processes, and has little or no effect on the pharmacokinetics of other drugs examined.

Its metabolism and pharmacokinetics are to some degree affected by the induction or inhibition of drug metabolizing enzyme s. From a pharmacokinetic standpoint, drug interactions involving paroxetine are considered unlikely to be a frequent occurrence. Data available have failed to reveal any correlation between plasma concentrations of paroxetine and its clinical effects either efficacy or adverse events.

Abstract Paroxetine is well absorbed from the gastrointestinal tract, and appears to undergo first-pass metabolism which is partially saturable. Publication types Review. In comparison with other selective serotonin uptake inhibitors paroxetine is 2 to 23 times more potent. With the exception of a low affinity to muscarinic receptors, which is not relevant for therapeutic effects, it does not interact directly with monoamine neurotransmitter receptors.

Paroxetine is applied orally at single daily doses of 20 to 50 mg and well absorbed from the gastrointestinal tract. Maximal blood levels are reached 2 to 8 hours after oral administration.

Paroxetine is eliminated after transformation in the liver into pharmacologically inactive metabolites. High affinity to the cytochrome P isoenzyme CYP2D6 indicates that interferences occur with other drugs which are metabolized via the same isoenzyme.

Although clinical practice has not reported problematic drug interactions so far, comedications with tricyclic antidepressants should be avoided.