Depression Home > Effexor Warnings and Precautions

Some Effexor Warnings and Precautions

Some warnings and precautions of Effexor include:
  • Antidepressants (including Effexor) may increase the risk of suicidal thinking or behavior in children, teenagers, and adults (see Antidepressants and Suicide for more information). Therefore, if you notice any changes in symptoms or new symptoms while taking Effexor, talk with your healthcare provider immediately. Some of these symptoms may include: anxiety, hostility, agitation, panic, restlessness, hallucinations, extreme hyperactivity, and suicidal thinking or behavior (see Effexor and Suicide for more information).
  • Before prescribing Effexor for depression, your healthcare provider should make sure that you do not have bipolar disorder (instead of depression). Sometimes, the symptoms of bipolar disorder and depression are very similar, and Effexor can cause problems in people with bipolar disorder.
  • In previous studies, Effexor was shown to slightly increase blood pressure and heart rate. Your healthcare provider should monitor your blood pressure and heart rate while you are taking Effexor.
  • Antidepressants can cause a group of dangerous symptoms known as serotonin syndrome. Taking Effexor with other medications that affect serotonin can increase your risk of serotonin syndrome. These other medications can include other antidepressants, triptans (migraine medications), and several other medications (see Effexor Drug Interactions for more information). Contact your healthcare provider immediately if you have any possible symptoms of serotonin syndrome, including:
    • Confusion
    • Seeing or hearing things that are not really there (hallucinations)
    • Fast heartbeat (tachycardia)
    • Feeling faint
    • Fever
    • Sweating
    • Muscle spasms
    • Difficulty walking
    • Diarrhea.
  • Your healthcare provider should monitor your closely if you have glaucoma (a condition of the eye) while you are taking Effexor, as Effexor may make glaucoma worse.
  • Effexor may increase your risk for certain lung problems. Be sure to let your healthcare provider know right away if you have signs of lung problems, such as difficulty breathing, coughing, or chest pain.


  • Effexor can cause anxiety, nervousness, and insomnia. Tell your healthcare provider if you experience these symptoms while taking Effexor. 

  • Effexor may increase the risk of bleeding or bruising. This is probably most dangerous in people who already have a bleeding disorder or who take other medications that increase the risk of bleeding.


  • Effexor can cause a loss of appetite and weight loss. Usually, weight loss is small. However, it is possible to lose large amounts of weight while taking Effexor (see Effexor and Weight Loss).  


  • Effexor can cause seizures or high cholesterol, or may increase your risk of bleeding. Let your healthcare provider know if you have a seizure or if you notice any unusual bleeding (such as unusual bruising or blood in the stool) while taking Effexor.


  • This medication can cause false positives on some urine drug tests for phencyclidine (PCP) or amphetamines. If this happens, more specific tests can be done to confirm (or deny) the results of the initial test. 


  • Since Effexor is removed from the body using the liver and kidneys, you may need a lower Effexor dosage if you have liver or kidney problems.
  • Effexor can interact with certain other medications (see Effexor Drug Interactions).
  • You should talk with your doctor about whether to avoid alcohol while taking Effexor (see Alcohol and Effexor).
  • If you are elderly or are taking a diuretic, Effexor could cause low salt levels in the blood (hyponatremia). Salt levels generally return to "normal" when Effexor is discontinued.
  • If you are stopping Effexor, you should be monitored by a healthcare professional for Effexor withdrawal symptoms. If you do develop any symptoms of Effexor withdrawal -- such as irritability, anxiety, confusion, headache, lethargy, or insomnia -- your healthcare provider may slow down the rate at which the Effexor is stopped (see Effexor Withdrawal).
  • Effexor may affect your ability to perform complex tasks requiring mental and motor skills. Therefore, it is recommended that you become accustomed to its effect on you before performing activities that require mental or motor concentration (such as driving a car or operating machinery). Taking Effexor with alcohol or other medications that cause drowsiness can increase this effect.
  • Effexor is considered a pregnancy Category C medication. This means that Effexor may not be safe to use during pregnancy. Talk with your healthcare provider about the risks and benefits of using Effexor during pregnancy (see Effexor and Pregnancy for more information).
  • Effexor passes through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, be sure to talk with your healthcare provider about using Effexor (see Effexor and Breastfeeding).
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
List of references (click here):
Other Articles in This eMedTV Presentation

Topics & Medications


Related Channels

eMedTV Links
Copyright © 2006-2019 Clinaero, Inc.

eMedTV serves only as an informational resource. This site does not dispense medical advice or advice of any kind. Site users seeking medical advice about their specific situation should consult with their own physician. Click Terms of Use for more information.

This site complies with the HONcode standard for trustworthy health information:
verify here.