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Effexor Side Effects

Generic Name: venlafaxine

Note: This document contains side effect information about venlafaxine. Some of the dosage forms listed on this page may not apply to the brand name Effexor.

For the Consumer

Applies to venlafaxine: oral capsule extended release, oral tablet, oral tablet extended release

Along with its needed effects, venlafaxine (the active ingredient contained in Effexor) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking venlafaxine:

More common

  • Lack or loss of strength
  • severe headache
  • sweating

Less common

  • Blurred vision
  • chest pain
  • fast or irregular heartbeat
  • mood or mental changes
  • ringing or buzzing in the ears
  • suicidal thoughts


  • Actions that are out of control
  • convulsions
  • high fever
  • irritability
  • itching or skin rash
  • lightheadedness or fainting, especially when getting up suddenly from a sitting or lying position
  • menstrual changes
  • nervousness
  • problems with urinating or holding urine
  • severe muscle stiffness
  • talking, feeling, and acting with excitement that you cannot control
  • trouble breathing
  • unusually pale skin

Incidence not known

  • Agitation
  • bloody, black, or tarry stools
  • bloody stool or urine
  • dark urine
  • decreased frequency or amount of urine
  • diarrhea
  • drowsiness
  • fever
  • general feeling of tiredness or weakness
  • headache
  • increased thirst
  • light-colored stools
  • muscle cramps, spasms, or pain
  • nausea or vomiting
  • nosebleeds
  • overactive reflexes
  • poor coordination
  • red or purple spots on the skin
  • restlessness
  • shivering
  • stomach pain on the upper right side
  • swelling of the face, lower legs, ankles, hands, or fingers
  • trembling or shaking that is hard to control
  • twitching
  • unusual bruising
  • unusual tiredness or weakness
  • vomiting of blood or material that looks like coffee grounds
  • yellow eyes or skin

Some side effects of venlafaxine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Abnormal dreams
  • chills
  • constipation
  • decrease in sexual desire or ability
  • diarrhea
  • dry mouth
  • heartburn
  • increased sweating
  • loss of appetite
  • nausea
  • stomach pain or gas
  • stuffy or runny nose
  • tingling, burning, or prickly sensations
  • trouble sleeping
  • vomiting
  • weight loss

Less common

  • Change in taste
  • muscle tension
  • yawning

Incidence not known

For Healthcare Professionals

Applies to venlafaxine: oral capsule extended release, oral tablet, oral tablet extended release


Very common (10% or more): Nausea (up to 35%), dry mouth ( up to 17%), constipation (12%)
Common (1% to 10%): Vomiting, abdominal pain, diarrhea, dyspepsia, flatulence, eructation
Uncommon (0.1% to 1%): Bruxism, colitis, dysphagia, tongue edema, esophagitis, gastritis, gastroenteritis, gastrointestinal ulcer, gingivitis, glossitis, rectal hemorrhage, hemorrhoids, melena, stomatitis, mouth ulceration
Rare (less than 0.1%): Cheilitis, cholecystitis, cholelithiasis, duodenitis, esophageal spasm, hematemesis, gastrointestinal hemorrhage, gum hemorrhage, ileitis, intestinal obstruction, parotitis, periodontitis, proctitis, increased salivation, soft stools, tongue discoloration
Postmarketing reports: Pancreatitis[Ref]

Nervous system

Very common (10% or more): Headache (up to 38%), dizziness (up to 20%), somnolence (up to 20%), fatigue (11%), nervousness (up to 10%)
Common (1% to 10%): Tremor, paraesthesia, twitching, hypertonia, migraine, trismus, vertigo
Uncommon (0.1% to 1%): Myoclonus, dysgeusia, akathisia, apathy, ataxia, circumoral paraesthesia, CNS stimulation, emotional lability, euphoria, hallucinations, hostility, hyperesthesia, hyperkinesia, hypotonia, incoordination, neuralgia, neuropathy, seizure, abnormal speech, stupor
Rare (less than 0.1%): Akinesia, alcohol abuse, aphasia, bradykinesia, buccoclusal syndrome, cerebrovascular accident, loss of consciousness, dementia, dystonia, facial paralysis, feeling drunk, abnormal gait, Guillain-Barre Syndrome, hyperchlorhydria, hypokinesia, impulse control difficulties, neuritis, paresis, torticollis
Frequency not reported: Neuroleptic malignant syndrome (NMS), serotonergic syndrome, extrapyramidal reactions (including dystonia, and dyskinesia), tardive dyskinesia[Ref]


Common (1% to 10%): Hypertension, vasodilatation (mostly hot flashes/flushes), palpitation, chest pain
Uncommon (0.1% to 1%): Hypotension, postural hypotension, syncope, angina pectoris, arrhythmia, extrasystoles, peripheral vascular disorder (mainly cold feet and/or cold hands), thrombophlebitis
Rare (less than 0.1%): Aortic aneurysm, arteritis, first-degree atrioventricular block, bigeminy, bradycardia, bundle branch block, capillary fragility, cardiovascular disorder (mitral valve and circulatory disturbance), coronary artery disease, congestive heart failure, heart arrest, mucocutaneous hemorrhage, myocardial infarct, pallor
Postmarketing reports: QT prolongation, ventricular fibrillation, ventricular tachycardia (including torsades de pointes)[Ref]


Very common (10% or more): Abnormal ejaculation (up to 16%)
Common (1% to 10%): Impotence, decreased libido, anorgasmia, erectile dysfunction, impaired urination, dysuria, metrorrhagia, prostatic disorder (prostatitis and enlarged prostate), vaginitis
Uncommon (0.1% to 1%): Menorrhagia, urinary retention, pelvic pain, cystitis, hematuria, leukorrhea, nocturia, bladder pain, breast pain, polyuria, pyuria, urinary incontinence, urinary urgency, vaginal hemorrhage
Rare (less than 0.1%): BUN increased, creatinine increased, glucosuria, balanitis, breast discharge, breast engorgement, breast enlargement, endometriosis, fibrocystic breast, calcium crystalluria, cervicitis, ovarian cyst, gynecomastia (male), kidney calculus, kidney pain, mastitis, menopause, oliguria, orchitis, pyelonephritis, salpingitis, urolithiasis, uterine spasm, vaginal dryness
Postmarketing reports: Menstrual disorders associated with
increased bleeding or increased irregular bleeding, proteinuria[Ref]


Very common (10% or more): Sweating (up to 14%)
Uncommon (0.1% to 1%): Photosensitivity, rash, acne, alopecia, brittle nails, contact dermatitis, dry skin, eczema, skin hypertrophy, maculopapular rash, psoriasis, urticaria
Rare (less than 0.1%): Erythema nodosum, exfoliative dermatitis, lichenoid dermatitis, hair discoloration, skin discoluration, furunculosis, leukoderma, petechial rash, pustular rash, vesiculobullous rash, seborrhea, skin atrophy, skin striae
Postmarketing reports: Night sweats, erythema multiforme, Stevens-Johnson syndrome, pruritus, toxic epidermal necrolysis[Ref]


Very common (10% or more): Asthenia (up to 19%)
Common (1% to 10%): Accidental injury, trauma
Uncommon (0.1% to 1%): Face edema, malaise, intentional injury
Postmarketing reports: Chills[Ref]


Uncommon (0.1% to 1%): Abnormal liver function tests
Rare (less than 0.1%): Hepatitis, jaundice, bilirubinemia[Ref]


Very common (10% or more): Insomnia (up to 25%)
Common (1% to 10%): Abnormal dreams, depression, agitation, anxiety
Uncommon (0.1% to 1%): Hallucination, derealization, apathy, hypomania
Rare (less than 0.1%): Mania
Frequency not reported: Suicidal ideation, suicidal behaviors, delirium, aggression
Postmarketing reports: Confusion, depersonalization[Ref]


Uncommon (0.1% to 1%): Ecchymosis, mucous membrane bleeding, anemia, leukocytosis, leukopenia, lymphadenopathy, thrombocythemia, thrombocytopenia
Rare (less than 0.1%): Prolonged bleeding time, basophilia, cyanosis, eosinophilia, lymphocytosis, multiple myeloma, purpura
Postmarketing reports: Blood dyscrasias (including agranulocytosis, aplastic anemia, neutropenia, pancytopenia)[Ref]


Common (1% to 10%): Neck pain
Uncommon (0.1% to 1%): Neck rigidity, arthritis, arthrosis, bone pain, bone spurs, bursitis, leg cramps, myasthenia, tenosynovitis
Rare (less than 0.1%): Pathological fracture, myopathy, osteoporosis, osteosclerosis, plantar fasciitis, rheumatoid arthritis, tendon rupture
Postmarketing reports: Rhabdomyolysis[Ref]


Common (1% to 10%): Abnormal vision, abnormality of accommodation, mydriasis
Uncommon (0.1% to 1%): Cataract, conjunctivitis, corneal lesion, diplopia, dry eyes, eye pain, photophobia, visual field defect
Rare (less than 0.1%): Blepharitis, chromatopsia, conjunctival edema, exophthalmos, angle-closure glaucoma, retinal hemorrhage, subconjunctival hemorrhage, keratitis, miosis, papilledema, decreased pupillary reflex, scleritis, uveitis[Ref]


Common (1% to 10%): Increased serum cholesterol , weight loss, decreased appetite, anorexia
Uncommon (0.1% to 1%): Hyponatremia, weight gain, increased alkaline phosphatase, dehydration, hyperglycemia, hyperlipemia, hypokalemia
Rare (less than 0.1%): Syndrome of inappropriate antidiuretic hormone secretion (SIADH), alcohol intolerance, diabetes mellitus, gout, hemochromatosis, hypercalcinuria, hyperkalemia, hyperuricemia, hypocholesteremia, hypoglycemia, hypophosphatemia, hypoproteinemia, uremia[Ref]


Common (1% to 10%): Pharyngitis, yawning, bronchitis, dyspnea
Uncommon (0.1% to 1%): Asthma, chest congestion, epistaxis, hyperventilation, laryngismus, laryngitis, pneumonia, voice alteration
Rare (less than 0.1%): Atelectasis, hemoptysis, hypoventilation, hypoxia, larynx edema, pleurisy, pulmonary embolus, sleep apnea
Postmarketing reports: Pulmonary eosinophilia[Ref]


Very rare (less than 0.1%): Anaphylaxis[Ref]


Common (1% to 10%): Infection
Uncommon (0.1% to 1%): Moniliasis
Rare (less than 0.1%): Appendicitis, bacteremia, cellulitis[Ref]


Rare (less than 0.1%): Goiter, hyperthyroidism, hypothyroidism, thyroid nodule, thyroiditis
Postmarketing reports: Increased prolactin[Ref]


The most commonly reported side effects were headache, dizziness, somnolence, insomnia, and nausea.[Ref]


Rare (less than 0.1%): Carcinoma[Ref]


1. "Product Information. Effexor (venlafaxine)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.