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.

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

Rare

• 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

• Night sweats

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

The most commonly reported side effects were nausea, headache, somnolence, and dizziness.

Very common (10% or more): Nausea (up to 58%), dry mouth (up to 22%), constipation (up to 15%)

Common (1% to 10%): Abdominal pain, diarrhea, dyspepsia, eructation, flatulence, vomiting

Uncommon (0.1% to 1%): Circumoral paresthesia, colitis, dysphagia, esophagitis, gastritis, gastroenteritis, gastrointestinal hemorrhage, gastrointestinal ulcer, gingivitis, glossitis, hemorrhoids, melena, mouth ulceration, oral moniliasis, rectal hemorrhage, stomatitis, tongue edema

Rare (less than 0.1%): Abdominal distention, buccoglossal syndrome, cheilitis, cholecystitis, cholelithiasis, duodenitis, esophageal spasm, gastroesophageal reflux disease, gum hemorrhage, hematemesis, hyperchlorhydria, ileitis, increased salivation, intestinal obstruction, pancreatitis, parotitis, periodontitis, proctitis, salivary gland enlargement, soft stools, tongue discoloration

Very common (10% or more): Headache (up to 38%), somnolence (up to 26.1%), dizziness (up to 23.9%), tremor (up to 10.2%)

Common (1% to 10%): Akathisia, amnesia, dysgeusia, hypertonia, hypesthesia, increased muscle tone, migraine, paresthesia, sedation, taste perversion, vertigo

Uncommon (0.1% to 1%): Abnormal coordination, abnormal speech, ataxia, balance disorder, central nervous system (CNS) stimulation, dyskinesia, hyperesthesia, hyperkinesia, hypotonia, incoordination, myoclonus, neuralgia, neuropathy, parosmia, seizure, syncope, stupor, taste loss, visual field defect

Rare (0.1% to 0.01%): Abnormal gait, akinesia, aphasia, bradykinesia, cerebral ischemia, cerebrovascular accident, convulsion, dementia, dystonia, facial paralysis, Guillain-Barre Syndrome, hypokinesia, loss of consciousness, neuritis, neuroleptic malignant syndrome (NMS), nystagmus, paresis, reflexes decreased, reflexes increased, serotonin syndrome, torticollis

Very rare (less than 0.01%): Extrapyramidal reactions, tardive dyskinesia

Frequency not reported: Impaired coordination, sensory disturbance

Postmarketing reports: Coordination abnormal, impaired balance, involuntary movements, NMS-like reactions, shock-like electrical sensations

Very common (10% or more): Insomnia (up to 24%), nervousness (up to 21.3%), abnormal orgasm (up to 12.5%), anxiety (up to 11.2%)

Common (1% to 10%): Abnormal dreams, abnormal thinking, agitation, anorgasmia, confusion, depersonalization, depression, libido decreased, orgasm disturbance, orgasmic dysfunction

Uncommon (0.1% to 1%): Apathy, bruxism, derealization, emotional lability, euphoria, hallucination, hostility, hypomania, libido increased, mania, manic reaction, psychosis, suicidal ideation, suicide attempt, withdrawal syndrome

Rare (less than 0.1%): Alcohol abuse, delirium, delusions, homicidal ideation, hysteria, impulse control difficulties, paranoid reaction, psychotic depression, psychomotor restlessness

Frequency not reported: Aggression, delayed orgasm, increased dreaming, intense dreams, nightmares, other sleep disorders, self-harm, sleep disturbances, suicidal behaviors, vivid dreams, withdrawal symptoms

Postmarketing reports: Catatonia, confusional state, panic, paranoia, psychotic disorder

Very common (10% or more): Sweating (up to 19.3%), night sweats (up to 11.4%)

Common (1% to 10%): Ecchymosis, hyperhidrosis, pruritus, rash

Uncommon (0.1% to 1%): Acne, alopecia, brittle nails, contact dermatitis, dry skin, eczema, face edema, maculopapular rash, photosensitivity reaction, psoriasis, skin hypertrophy, urticaria

Rare (less than 0.1%): Cellulitis, erythema multiforme, erythema nodosum, exfoliative dermatitis, furunculosis, granuloma, hair discoloration, hirsutism, leukoderma, lichenoid dermatitis, miliaria, mucocutaneous hemorrhage, petechial rash, pruritic rash, purpura, pustular rash, seborrhea, skin atrophy, skin discoloration, skin striae, Stevens-Johnson syndrome, sweating decreased, toxic epidermal necrolysis, vesiculobullous rash

Very common (10% or more): Anorexia (up to 20%)

Common (1% to 10%): Blood cholesterol increased, decreased appetite, increased appetite, weight gain, weight loss

Uncommon (0.1% to 1%): Dehydration, hyperglycemia, hyperlipemia, hyperlipidemia, hypokalemia, hyponatremia, increased alkaline phosphatase, thirst

Rare (less than 0.1%): Alcohol intolerance, diabetes mellitus, gout, hemochromatosis, hypercholesteremia, hyperkalemia, hyperphosphatemia, hyperuricemia, hypocholesteremia, hypoglycemia, hypophosphatemia, hypoproteinemia

Frequency not reported: Height changes, loss of appetite, weight changes

Postmarketing reports: Lactate dehydrogenase (LDH) increased

Very common (10% or more): Asthenia (up to 19%)

Common (1% to 10%): Accidental injury, chills, fatigue, fever, tinnitus, trauma

Uncommon (0.1% to 1%): Hyperacusis, intentional injury, malaise, otitis media

Rare (less than 0.1%): Abortion, deafness, energy increased, feeling drunk, healing abnormal, labyrinthitis, menopause, motion sickness, otitis externa

Frequency not reported: Discontinuation syndrome, pain

Postmarketing reports: Congenital anomalies

Very common (10% or more): Abnormal ejaculation (up to 16%)

Common (1% to 10%): Albuminuria, enlarged prostate, erectile dysfunction, impotence, metrorrhagia, pollakiuria, prostatic disorder, prostatitis, urinary frequency, urinary hesitation, urinary retention, urination impaired, vaginitis

Uncommon (0.1% to 1%): Amenorrhea, bladder pain, breast pain, cystitis, dysuria, hematuria, leukorrhea, menorrhagia, nocturia, pelvic pain, polyuria, prostate irritability, pyuria, urinary incontinence, urinary urgency, vaginal hemorrhage

Rare (less than 0.1%): Balanitis, breast discharge, breast engorgement, breast enlargement, calcium crystalluria, cervicitis, endometriosis, galactorrhea, hypercalcinuria, hypomenorrhea, lactation (female), mastitis, menstrual disorders associated with increased bleeding or increased irregular bleeding, ovarian cyst, orchitis, prolonged erection, salpingitis, urolithiasis, uterine hemorrhage, uterine spasm, vaginal dryness

Frequency not reported: Delayed ejaculation, dysmenorrhea

Postmarketing reports: Proteinuria

Common (1% to 10%): Chest pain, edema, hot flashes/hot flush, hypertension/increased blood pressure, palpitation, postural hypotension, substernal chest pain, tachycardia, vasodilation

Uncommon (0.1% to 1%): Angina pectoris, arrhythmia, bradycardia, cold feet, cold hands, extrasystoles, hypotension, orthostatic hypotension, peripheral vascular disorder, thrombophlebitis

Rare (less than 0.1%): Aortic aneurysm, arteritis, bigeminy, bundle branch block, capillary fragility, cardiovascular disorder (mitral valve and circulatory disturbance), coronary artery disease, congestive heart failure, cyanosis, ECG QT prolonged, first-degree atrioventricular block, heart arrest, hematoma, myocardial infarct, pallor, sinus arrhythmia, torsade de pointes, ventricular fibrillation, ventricular tachycardia

Postmarketing reports: Atrial fibrillation, deep vein thrombophlebitis, ECG abnormalities, stress cardiomyopathy, supraventricular tachycardia, Takotsubo cardiomyopathy, ventricular extrasystole

Common (1% to 10%): Bronchitis, cough increased, dyspnea, pharyngitis, sinusitis, yawn/yawning

Uncommon (0.1% to 1%): Asthma, chest congestion, epistaxis, hyperventilation, laryngismus, laryngitis, pneumonia, voice alteration

Rare (less than 0.1%): Atelectasis, hemoptysis, hypoventilation, hypoxia, interstitial lung disease, larynx edema, pleurisy, pulmonary embolus, pulmonary eosinophilia, sleep apnea

Frequency not reported: Rhinitis, upper respiratory infection, upper respiratory tract infection

Common (1% to 10%): Abnormality of accommodation, abnormal vision, blurred vision, mydriasis

Uncommon (0.1% to 1%): Cataract, conjunctivitis, corneal lesion, diplopia, dry eyes, eye pain, photophobia

Rare (less than 0.1%): Angle-closure glaucoma, blepharitis, chromatopsia, conjunctival edema, decreased pupillary reflex, exophthalmos, eye hemorrhage, keratitis, miosis, papilledema, retinal hemorrhage, scleritis, subconjunctival hemorrhage, uveitis

Frequency not reported: Difficulty focusing eyes

Common (1% to 10%): Neck pain, trismus, twitching

Uncommon (0.1% to 1%): arthritis, arthrosis, bone pain, bone spurs, bursitis, leg cramps, myasthenia, neck rigidity, tenosynovitis

Rare (less than 0.1%): Muscle cramp, muscle spasms, musculoskeletal stiffness, myopathy, osteoporosis, osteosclerosis, pathological fracture, plantar fasciitis, rhabdomyolysis, rheumatoid arthritis, tendon rupture

Frequency not reported: Arthralgia, back pain, myalgia

Postmarketing reports: Bone fracture, creatine phosphokinase (CPK) increased

Common (1% to 10%): Flu syndrome, infection

Uncommon (0.1% to 1%): Moniliasis

Rare (less than 0.1%): Appendicitis, bacteremia

Uncommon (0.1% to 1%): Anemia, leukocytosis, leukopenia, lymphadenopathy, mucous membrane bleeding, mucosal hemorrhage, thrombocythemia, thrombocytopenia

Rare (less than 0.1%): Agranulocytosis, aplastic anemia, basophilia, blood dyscrasias, eosinophilia, lymphocytosis, neutropenia, pancytopenia, prolonged bleeding time

Postmarketing reports: INR increased, prolonged partial thromboplastin time, prothrombin time increased

Uncommon (0.1% to 1%): Abnormal liver function tests, ALT increased, AST increased

Rare (less than 0.1%): Biliary pain, bilirubinemia, cholecystitis, cholelithiasis, hepatitis, jaundice, liver tenderness

Postmarketing reports: Fatty liver, GGT elevation, hepatic reactions, liver damage, liver failure, liver necrosis

Uncommon (0.1% to 1%): Kidney calculus, kidney pain

Rare (less than 0.1%): Anuria, blood urea nitrogen (BUN) increased, creatinine increased, glycosuria, kidney function abnormal, oliguria, pyelonephritis, uremia

Postmarketing reports: Renal failure

Uncommon (0.1% to 1%): Angioedema

Rare (less than 0.1%): Anaphylactic reaction, anaphylaxis

Frequency not reported: Hypersensitivity

Rare (0.1% to 0.01%): Goiter, gynecomastia (male), hyperthyroidism, hypothyroidism, inappropriate antidiuretic hormone secretion (SIADH)/syndrome of inappropriate antidiuretic hormone secretion, thyroid nodule, thyroiditis

Very rare (less than 0.01%): Blood prolactin increased

Rare (less than 0.1%): Carcinoma, fibrocystic breast, multiple myeloma