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venlafaxine (ven-la-fax-een)

Effexor, Effexor XR


Therapeutic: antidepressants, antianxiety agents

Pharmacologic: selective serotonin/norepinephrine reuptake inhibitors


Major depressive disorder. Generalized anxiety disorder (Effexor XR only). Social anxiety disorder (Effexor XR only). Panic disorder (Effexor XR only). Unlabeled Use: Premenstrual dysphoric disorder.


Inhibits serotonin and norepinephrine reuptake in the CNS. Therapeutic Effects: ↓ in depressive symptomatology, with fewer relapses/recurrences. ↓ anxiety. ↓ in panic attacks.

Adverse Reactions/Side Effects

CNS: NEUROLEPTIC MALIGNANT SYNDROME, SEIZURES, abnormal dreams, anxiety, dizziness, headache, insomnia, nervousness, weakness, abnormal thinking, agitation, confusion, depersonalization, drowsiness, emotional lability, worsening depression. EENT: rhinitis, visual disturbances, epistaxis, tinnitus. CV: chest pain, hypertension, palpitations, tachycardia. GI: abdominal pain, altered taste, anorexia, constipation, diarrhea, dry mouth, dyspepsia, nausea, vomiting, weight loss. GU: sexual dysfunction, urinary frequency, urinary retention. Derm: ecchymoses, itching, photosensitivity, skin rash. Neuro: paresthesia, twitching. Misc: SEROTONIN SYNDROME, chills, bleeding, yawning.


Examination and Evaluation

  • Watch for signs of neuroleptic malignant syndrome, including hyperthermia, diaphoresis, generalized muscle rigidity, altered mental status, tachycardia, changes in blood pressure (BP), and incontinence. Symptoms typically occur within 4–14 days after initiation of drug therapy, but can occur at any time during drug use. Report these signs to the physician immediately.

  • Monitor and immediately report signs of serotonin syndrome, including hyperthermia, rigidity, myoclonus, and autonomic instability with fluctuating vital signs and extreme agitation that may proceed to delirium and coma. Patients should not take venlafaxine with other drugs that increase serotonin levels (e.g., MAO inhibitors).

  • Be alert for new seizures or increased seizure activity, especially at the onset of drug treatment. Document the number, duration, and severity of seizures, and report these findings to the physician immediately.

  • Be alert for increased depression and suicidal thoughts and ideology, especially when initiating drug treatment, and in children and teenagers. Notify physician or other mental health care professional immediately if patient exhibits worsening depression.

  • Monitor anxiety, nervousness, agitation, confusion, emotional lability, expression of abnormal thoughts, or other alterations in mood and behavior. Notify physician if these symptoms become problematic.

  • Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report a rapid heart rate (tachycardia) or signs of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

  • Assess BP and compare to normal values (See Appendix F). Report a sustained increase in BP (hypertension).

  • Assess signs of paresthesia (numbness, tingling) or muscle twitching. Perform objective tests including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

  • Assess dizziness and drowsiness that might affect gait, balance, and other functional activities (See Appendix C...

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