Posted by PaulB on June 16, 2001, at 10:50:05
In reply to Paroxetine (Paxil) and Reboxetine (Edronax) ?, posted by ben on June 16, 2001, at 9:48:27
> Does anyone know if this combo may be dangerous ? Are there any interactions between this two meds ? I think of the CYP450 enzymes. Paroxetine is a potent inhibitor of 2D6. What about Reboxetine ? Is it for anyone an effective combo ?
This was something that I looked into with my doctor at one point. After doing some research and making some enquiries we got the information we were looking for.From a Summary of the Product Characteristics of Reboxetine:
'The route of metabolism of Reboxetine is unknown and it is therefore difficult to predict interactions between reboxetine and other drugs. The cytochrome P450 enzyme does not seem to be involved in reboxetine metabolism. Because of reboxetine's narrow therapeutic margin, inhibition of its elimination is a major concern. The potential for co-prescribed drugs to inhibit reboxetine elimination has not been tested. Edronax, therefore should not be given together with drugs known to inhibit other major drug metabolising enzymes other than CYP2D6.
Information regarding reboxetines potential to influence the pharmacokinetics of other drugs is limited. In vitro data show that reboxetine in high concentrations inhibits CYP3A4 and CYP2D6. Until further in vivo data are available , reboxetine should be used with caution when prescribed with drugs metabolised by CYP3A4 or CYP2D6 that have a narrow therapeutic window.'
The SSRI Paroxetine itself, along with Fluoxetine are the most potent inhibitors of CYP2D6 and inhibit their own metabolism by themselves, the only consequence being some strange blood levels of the drugs. I personally think it wouldnt be a problem. It all depends on the drug i.e.Xanax and Nefazadone could create some BIG problems as Xanax levels could increase dramatically.
Paroxetine is like Reboxetine in that it is highly selective and very potent in its mechanism of action. Its indicated for the long-term treatment of depression and may be more effective for severe depressives than SSRI's and of course depression associated with lack of energy and motivation.
When I initially suggested the co-administration of these drugs it seemed to make sense to me but my doctor said that it wasnt 'the done thing'. Generally Reboxetine is used on its own if a patient has relapsed on an SSRI. If you were looking for the dual mode of action Venlafaxine is more commonly used. I was given 75mg of the XR form. Venlafaxine does not possess Reboxetines highly selective noradenergic effects nor Paroxetines highly selective seroternergic effects but as the dose is increased it is said to have a more powerful effect overall and as the dosage increases it begins to affect the dopamine pathways in the brain as well, to what extent I dont know. It seems Effexor XR is a hot topic here at Dr-Bobs and I think a lot of people are doing well on it.
poster:PaulB
thread:66710
URL: http://www.dr-bob.org/babble/20010612/msgs/66718.html