Posted by Cam W. on October 19, 2000, at 7:17:54
In reply to Re: input from Dr. Stahl, posted by JohnB on October 18, 2000, at 23:17:39
John - Prozac's long half-life makes it an attractive drug to augment with Effexor in several situations. As Dr.Stahl mentioned, Effexor augmentation is especially done when the Prozac (at a couple different dosages) has brought partial relief of depressive symptoms. This partial serotonergic effect can be maintained or slightly inhanced (watch for signs of serotonin syndrome) at low Effexor doses and, as you increase the Effexor dose, the NRI portion kicks in hopefully bringing even more relief.
At this point one could maybe try to take away the Prozac, but if there are hints of non-compliance to the medication therapy, the Prozac should be left in the regimen to avoid serotonin withdrawl symptoms (eg if the person is missing too many consecutive Effexor doses). Non-compliance with Effexor can bring rapid onset of withdrawl symptoms because of this drug's short half-life. Prozac's 100 hour half-life prevents the onset of serotonin withdrawl syndrome in non-compliant patients. The absence of the symptoms of this syndrome may improve the compliance of someone taking Effexor.
Also, some researchers have stated that while SRIs block the serotonin reuptake pump, they may do so at different sites on the pump. Thus, theoretically a combination of both Prozac and Effexor may give a slightly more effective reuptake blockade than either drug separately, giving more than just an additive serotonergic effect.
Also, you have to look at side effect profiles of the 2 drugs. Both drugs have different affinities for secondary receptors, those that contribute to side effects. Using both drugs together gives enhanced serotonergic activity with decreased side effects caused by the different secondary receptor concentrations of the 2 drugs (eg decreased intensity of cholinergic, antihistaminergic & or alpha-adrenergic side effects, etc.).
There are a couple other reasons for this strategy, but I can't come up with them off of the top of my head. Hope this helps - Cam
poster:Cam W.
thread:45713
URL: http://www.dr-bob.org/babble/20001012/msgs/46743.html