What is Effexor?
(Venlafaxine)

Effexor, also known as generic venlafaxine HCI, is an antidepressant that is also sold in an extended-release form as Effexor XR. It is an SNRI or serotonin norepinephrine reuptake inhibitor, which means that it inhibits the reuptake of norepinephrine as well as serotonin. Wyeth, now owned by Pfizer, is the manufacturer of Effexor.

The FDA has placed Effexor in the Pregnancy Category C class of drugs which says that animal reproduction studies have shown an adverse effect on the fetus and there are no adequate well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risk. The Pregnancy Categories measure the teratogenic effects a drug has on a fetus (teratogenic or embryocidal or other). Teratogenic means that a drug or other substance is capable of interfering with the development of a fetus. Embryocidal pertains to the killing of an embryo.

The FDA also lists the following non-teratongenic effects:

Neonates [newborns] exposed to Effexor XR, other SNRIs (Serotonin and Norepinephrine Reuptake Inhibitors), or SSRIs (Selective Serotonin Reuptake Inhibitors), late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. (...)

Nursing Mothers
Venlafaxine [Effexor] and ODV have been reported to be excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from Effexor XR, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.