Two questions. Was your doctor aware of your taking Effexor prior to proscribing Tramadol? Do you have a seizure disorder?
It is probably safe to take these medications in combination. They have completely different mechanisms of action. While it is true that Effexor is an Serotonin-norepinephrine reuptake inhibitor (SNRI) this is not true about Tramadol. As you correctly stated Tramadol is not a Monoamine oxidase inhibitor (MAOI). However, it is believed that it can increase the risk of Serotonin syndrome in combination with a SNRI or Selective Serotonin uptake inhibitor (SSRI). Be aware of the signs and symptoms of Serotonin syndrome:
* Cognitive effects: mental confusion, hypomania, hallucinations, agitation, headache, coma.
* Autonomic effects: shivering, sweating, hyperthermia, hypertension, tachycardia, nausea, diarrhea.
* Somatic effects: myoclonus (muscle twitching), hyperreflexia (manifested by clonus), tremor.
In addition Tramadol by itself can lower your seizure threshold if you have a seizure disorder. It is believed that this phenomenon is aggravated by SSRIs.
I am sure that this combination should be fine with most people, but make sure that your doctor is aware of all medications and drugs that you are taking.