Okay...I see now. That effect is not the same as increasing blood flow to the limbs... those arteries are larger.
Serotonin can cause vaso active responses in some sensitive people. Mostly people who already have alot of serotonin genetically. The SSRIs like Prozac, Paxil, Lexapro do not have the
norepi reuptake functions. So they cause more flushing than SNRIs like Savella, Cymbalta, and Effexor.
The flushing is not predictable either, and often is mediated by emotions and/or food.
Overall Cymbalta, with its combination actions, is more vasoconstrictive than other SSRIs. It has warnings on it for
people with hypertension, for example.
None of these drugs is a potent vasodilator however, like the calcium channel blockers, Cardizem, Calan, Norvasc, or like Nitroglycerine, which is so powerful it dilates vessels in the brain causing headache.
It is a matter of degree. I would not expect Cymbalta to restore cold hands and feet therefore. In fact it might make them colder depending on the neurotransmitter balance that person has.
So don't expect that action as predictable.
The vasoactive biogenic amines also include histamine.
Here is the new histamine thread I am building, as I find new information:
http://neurotalk.psychcentral.com/thread161714.html
When histamine or serotonin is available to skin suddenly, there is tingling, burning, flushing. But blood pressure is not typically affected. The only blood pressure effects of SSRIs (not so much Cymbalta but possible) is a sudden orthostatic effect when standing up suddenly. And this varies from person to person as well. You will not find the antidepressants listed as "vasodilators" for this reason. It is more of a potential side effect than a direct drug effect.
http://highbloodpressure.about.com/o...epressants.htm
Mostly from I've read and seen, the vasoactive effects are on the
skin only. Not on the receptors of all the blood vessels, leading to and including limbs themselves. Blood pressure lowering drugs dilate many larger vessels, and this is how they lower blood pressure. Massive doses, as in an overdose however, may be quite different.