Is reboxetine (Edronax) more likely to pharmacologically interact with paroxetine (Seroxat) than wi

Fråga: Is reboxetine (Edronax) more likely to pharmacologically interact with paroxetine (Seroxat) than with other selective serotonin reuptake inhibitors (SSRI:s)?

Sammanfattning: There is no obvious risk of pharmacokinetic interactions between reboxetine and paroxetine, although available data is limited. The pharmacodynamic interaction potential should not differ between the SSRI:s.

Svar: No reports of drug interactions between paroxetine and reboxetine were found in Drugline, Medline or standard pharmacological literature. Data on interactions between reboxetine and other SSRI:s is also very limited.

Reboxetine, a selective norepinephrine reuptake inhibitor, and an SSRI could theoretically have additive effects, combined mimicking the actions of an unselective antidepressant. Since all SSRI:s are highly serotonin-selective, the pharmacodynamic interaction potential should not differ between substances.

Reboxetine is extensively metabolised, although the enzymatic mechanisms are unknown. However, it has been suggested that the cytochrome P450 isoenzyme CYP3A4 is involved (2). Neither fluoxetine nor quinidine affects the metabolism of reboxetine, speaking against an involvement of CYP2D6 (1-2).

Paroxetine is mainly metabolised by CYP2D6 and is a potent inhibitor of this enzyme. It is not known to affect drugs metabolised by other enzymes (1). Hence, pharmacokinetic interactions between paroxetine and reboxetine seem unlikely. 1 Caccia S. Metabolism of the newer antidepressants. An overview of the pharmacological and pharmacokinetic implications. Clin Pharmacokinet 1998;34:281-302. 2 Drugdex(R) System; Micromedex, Inc., Englewood, Colorado (Edition expires (9/2001))