Efexxor ( venlafaxine) interacts adversely with Nortryptiline and hence the two must not be taken together. Symptoms of the drug interaction may be altered mental status, irritability, altered consciousness, confusion, hallucinations, coma, tachycardia, hyperthermia, diaphoresis, shivering, neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia, and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea. Please consult a physician for the drug prescription. Hope this helps you. Take care and regards!