Effexor Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: skin rash or hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Contact your doctor promptly if you have any of the following side effects, especially if they are new symptoms or if they get worse: mood changes, anxiety, panic attacks, trouble sleeping, irritability, agitation, aggressiveness, severe restlessness, mania (mental and/or physical hyperactivity), thoughts of suicide or hurting yourself. Call your doctor at once if you have any of these serious side effects:

  • increased blood pressure (severe headache, blurred vision);
  • nausea, vomiting, diarrhea, fever, fast heartbeat; hallucinations, loss of coordination, fainting, coma;
  • seizure (convulsions);
  • extreme thirst with headache, nausea, vomiting, and weakness; or
  • easy bruising or bleeding.

Other less serious side effects are more likely to occur, such as:

  • drowsiness, dizziness, nervousness, or anxiety;
  • dry mouth, increased sweating;
  • nausea, vomiting, diarrhea, constipation;
  • decreased sex drive, impotence, or difficulty having an orgasm;
  • headache, blurred vision;
  • tremor or chills; or
  • changes in appetite or weight.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What other drugs will affect Effexor?

Before taking Effexor, tell your doctor if you are using any of the following medicines:

  • cimetidine (Tagamet, Tagamet HB);
  • warfarin (Coumadin);
  • ketoconazole (Nizoral);
  • tryptophan (sometimes called L-tryptophan);
  • haloperidol (Haldol) or risperidone (Risperdal);
  • almotriptan (Axert), frovatriptan (Frova), sumatriptan (Imitrex), naratriptan (Amerge), rizatriptan (Maxalt), or zolmitriptan (Zomig); or
  • any other antidepressants such as amitriptyline (Elavil), amoxapine (Ascendin), citalopram (Celexa), clomipramine (Anafranil), desipramine (Norpramin), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), imipramine (Tofranil), nortriptyline (Pamelor), paroxetine (Paxil), protriptyline (Vivactil), sertraline (Zoloft), or trimipramine (Surmontil).

If you are using any of these drugs, you may not be able to use Effexor, or you may need dosage adjustments or special tests during treatment.There may be other drugs not listed that can affect Effexor. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.