Effexor Side Effects

Effexor (venlafaxine) is an SNRI antidepressant medication which works by increasing activity of serotonin and norepinephrine in the brain. It may cause side effects similar to SSRI medications, some of which may be serious or life-threatening.

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Quick Summary

Effexor Common Side Effects

Effexor (venlafaxine) is an SNRI antidepressant medication which works by affecting norepinephrine and serotonin levels in certain areas of the brain. Like all medications it may cause side effects, most of which are not serious and will go away with time.

Common side effects of Effexor include:

  • Headaches
  • Dry mouth
  • Nausea
  • Sedation
  • Increased perspiration
  • Constipation
  • Sexual dysfunction

Effexor Serious Side Effects

Effexor may also cause side effects or complications which are more severe or may be serious or life-threatening.

Serious side effects or complications of Effexor include:

  • Activation of manic state
  • Increased suicide risk
  • Serotonin Syndrome
  • Birth defects
  • Withdrawal effects

Severe side effects of Effexor should be reported to a health care professional right away. Sudden or severe symptoms such as changes in level of consciousness should treated as a medical emergency as they may be life-threatening.

Effexor Side Effects Overview

SNRI antidepressant, Effexor, may cause a number of side effects which can result in serious illness or injury. Severe Effexor side effects may include those affecting the cardiovascular and nervous system, the skin and musculoskeletal system, and may include birth defects when Effexor is taken during pregnancy.

Effexor is an antidepressant pharmaceutical medication used for treating major depressive disorder (MDD) and other mental problems. Effexor is also sometimes used to treat migraines and vasomotor instability, or hot flashes. Effexor side effects are very similar to side effects from SSRI, or selective serotonin reuptake inhibitor, medications. Effexor is slightly different from SSRI antidepressants because it is an SNRI, or serotonin norepinephrine reuptake inhibitor. However, Effexor side effects can be as dangerous as side effects from SSRIs.

Common Effexor Side Effects

Intended and unintended Effexor side effects are continuously recorded by the medical community in order to stay updated. This helps to keep patients safe from adverse complications. It is easier for doctors and other practitioners to treat patients when they can consider all potential problems.

Most common Effexor side effects:

  • headaches
  • dry mouth
  • nausea
  • increased perspiration

Other common Effexor side effects:

  • chills
  • confusion
  • dizziness
  • vision problems
  • increased tonicity (muscle tone)
  • loss of appetite
  • pupil dilation
  • depersonalization
  • sexual problems
  • menstrual problems
  • sedation
  • urinary problems
  • paresthesia (tingling)

Severe Effexor Side Effects

Though most side effects of Effexor are mild-to-moderate and may subside over time, some side effects are more severe, may be serious or even life-threatening.

Severe side effects may include:

  • Suicide risk
  • Activation of manic state in bipolar patients
  • Serotonin syndrome
  • Withdrawal
  • Birth defects

Suicide Risk Black Box Warning

Like other antidepressants, Effexor was given a black-box warning by the FDA due to an increased risk of suicide. A black-box or boxed statement warning is the most severe safety alert that can be issued by the FDA. It requires that information about increased suicide risk be printed at the top of all prescribing information.

Effexor’s black box warning states that the medication may increase the risk of suicidal thoughts and behaviors of children, adolescents and young adults. The risk may be highest in beginning periods after medication is started or dosage is changed.

Birth Defects

Effexor use has been associated with birth defects when the medication is taken during pregnancy. The FDA has designated venlafaxine as Pregnancy Category C which indicates that Effexor has caused harm to animals during testing but has not been fully tested in humans.

Effexor birth defects include:

  • Persistent pulmonary hypertension of the newborn, or PPHN
  • Heart defects and malformations
  • Respiratory distress
  • Physical defects such as cleft lip and palate
  • Anencephaly, or the absence of parts of the brain and skull
  • Craniosynostosis, which causes abnormal skull and brain growth
  • Omphalocele, or an abdominal defect that causes organs to protrude from the belly button
  • Miscarriage
  • Premature birth

After birth, nursing infants may develop side effects due to Effexor secretion in breast milk.

Newborns may develop symptoms such as:

  • Irregular appetite or difficulties feeding
  • Heart defects
  • Growth or development defects
  • Jitteriness or shaking
  • Seizures
  • Consistent or abnormally frequent crying

Pregnant and nursing women should discuss their medication use with their health care providers.

Effexor Serotonin Syndrome

Though it most commonly occurs in SSRI-type antidepressants, SNRI medications such as Effexor may also result in excessive serotonin buildup in the brain.

Symptoms may include:

  • Sudden increase in blood pressure or heart rate
  • High temperature
  • Unexpected muscle contractions
  • Changes in mental status
  • Loss of consciousness

Symptoms of serotonin syndrome should be treated as an emergency.

Effexor Withdrawal Syndrome

Stopping Effexor too suddenly may lead to discontinuation syndrome. Symptoms of withdrawal may be reduced by tapering off of the medication.

Effexor withdrawal symptoms:

  • loss of coordination
  • stomach cramps
  • severe headaches/migraines
  • extreme sleepiness
  • fatigue

Notwithstanding claims relating to this product, the drug/medical device remains approved by the U.S. FDA.