Question: Now that Pristiq has been out for awhile, what has been the clinical response with your patients compared with the Effexor XR formulation? Rumors have said it is more tolerable and less sexual side effects, although I have tried some samples, and it doesn’t seem to be as calming as Effexor, and I am unsure what the Pristiq 50mg dose is compare to a similar Effexor XR dosage?
Also what SSRI/SNRI tends to have the fewest sexual side effects?
Pristiq and Cymbalta seem to have less sexual side-effects than Effexor
and if Pristiq at 50mg is an adequate dose it should have the least
sexual effects. 90% of the first 570,000 treated with Pristiq have
stayed with a 50mg dose. This dose has the same efficacy in control
studies as 75-150 of Effexor with better tolerability. The drop out
rate due to side-effects is essentially the same as placebo.
When most people (normal metabolizers) take Effexor – 70% of the benefit
comes from Effexor being metabolized so the effects are very similar.
Pristiq does have a slightly higher ratio of norepinephrine effect
relative to serotonin than Effexor and this could account for your
impression that it’s not as calming – that is most likely a temporary
Because Pristiq doesn’t require the same liver metabolism as Effexor
there are less issues with drug drug interactions and tolerability for
those people (7-10% of Caucasians) who are poor metabolizers. Poor
metabolizers don’t usually do as well on Effexor and don’t usually
tolerate doses above 75mg. Some people do better on 100mg of Pristiq.
Pristiq is also more cost-effective, especially at 100mg dose – since
there is a 100mg tablet – whereas Effexor frequently requires 225mg or
more necessitating multiple capsules.
Wyeth is also getting ready to launch a program where they will pay 1/2
of your cost (copay or cash) as long as you take it on a continual
basis for life if necessary.