Venlafaxine

Venlafaxine is used to treat depression, anxiety, panic attacks, and social anxiety disorder (social phobia). It may improve your mood and energy level and may help restore your interest in daily living. It may also decrease fear, anxiety, unwanted thoughts, and the number of panic attacks. Venlafaxine is known as a serotonin-norepinephrine reuptake inhibitor (SNRI). It works by helping to restore the balance of certain natural substances (serotonin and norepinephrine) in the brain.

• Venlafaxine may also be used to treat hot flashes that occur with menopause.
• Venlafaxine is available under the following different brand names: Effexor, and Effexor XR.

Dosage Forms and Strengths

Tablet

• 25 mg
• 37.5 mg
• 50 mg
• 75 mg
• 100 mg

Tablet, extended release

• 37.5mg
• 75mg
• 150 mg
• 225 mg

Capsule, extended release

• 37.5 mg
• 75 mg
• 150 mg

Immediate release

• 75 mg/day orally divided every 8-12 hours initially; may be increased by up to 75 mg/day not faster than every 4 days
• Moderate: Up to 225 mg/day orally divided every 8-12 hours
• Severe: Up to 375 mg/day orally divided every 8-12 hours

Extended release

• 37.5-75 mg orally once daily initially; may be increased by 75 mg/day every 4 days; not to exceed 225 mg/day

Immediate release

• 25-50 mg/day orally divided every 8-12 hours initially; may be increased as tolerated by up to 25 mg/day no faster than every 4 days
• Moderate: Up to 225 mg/day orally divided every 8-12 hours
• Severe: Up to 375 mg/day orally divided every 8-12 hours

Extended release

• 37.5 mg orally once daily initially; may be increased by 37.5 mg/day every 4-7 days; not to exceed 225 mg/day

Pediatric (Off-label)

• Children: 37.5 mg/day orally initially
• Adolescents: 37.5-75 mg/day orally initially
• Maintenance: Children, 75-150 mg/day; adolescents, 150-300 mg/day

• Adult: Extended release: 37.5-75 mg orally once daily initially; may be increased by 75 mg/day every 4-7 days; not to exceed 225 mg/day
• Geriatric: Extended release: 37.5 mg orally once daily initially; may be increased by 37.5 mg/day every 4 days; not to exceed 225 mg/day

• Adult, Extended release: 75 mg orally once daily
• Dosages greater than 75 mg/day not shown to be more effective
• Geriatric, Extended release: 37.5 mg orally once daily; may be increased by 37.5 mg/day every 4 days

• Children: 37.5 mg/day orally initially
• Adolescents: 37.5-75 mg/day orally initially
• Maintenance: Children, 75-150 mg/day; adolescents, 150-300 mg/day

• Adult, Extended release: 37.5 mg orally once daily for 7 days, then 75 mg once daily; may be further increased by 75 mg/day every 7 days; not to exceed 225 mg/day
• Geriatric, Extended release: 37.5 mg orally once daily for 7 days, then 75 mg once daily; may be further increased by 37.5 mg/day every 7 days; not to exceed 225 mg/day

• Immediate release: 37.5 mg BID or 75 mg once/day; alternatively may titrate up beginning with 37.5 mg once/day for 1 week then 75 mg daily
• Extended release: 37.5-150 mg orally once daily for 4-12 weeks

• Extended release formulation: 37.5-300 mg/day

• Adult: 18.75-75 mg/day; may increase to 150 mg/day after 4 weeks; doses up to 225 mg/day used
• Children less than 40 kg: 12.5 mg/day orally initially; increase by 12.5 mg/week; not to exceed 50 mg/day divided twice daily
• Children 40 kg or more: 12.5 mg/day orally initially; increase by 25 mg/week; not to exceed 75 mg/day divided three times daily

• 75-225 mg/day orally; onset of relief may start in 1-2 weeks or take up to 6 weeks for full benefit

• Take with food
• If discontinuing therapy after 7 or more days, taper dosage

• Mild to severe renal impairment: Reduce dosage by 25-50%
• Mild to moderate hepatic impairment: Reduce dosage by 50%

Common side effects or health problems may include:

• Headache
• Nausea
• Insomnia
• Weakness
• Dizziness
• Ejaculation disorder
• Drowsiness
• Dry mouth
• Sweating
• Loss of appetite
• Nervousness
• Inability to orgasm
• Weight loss
• Abnormal vision
• High blood pressure (hypertension)
• Impotence
• Numbness and tingling
• Tremor
• Vasodilation
• Vomiting
• Weight gain
• Gas (flatulence)
• Itching
• Yawning
• Indigestion
• Twitching
• Dilated pupils

Other side effects of venlafaxine include:

• Agranulocytosis
• Anemia
• Aneurism
• Bacteremia
• Fainting
• Muscle weakness
• Reduced urination
• Skin swelling
• Suicide ideation/attempt

Postmarketing side effects of venlafaxine reported include:

• Chills
• Shortness of breath
• Interstitial lung disease

This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of this medicine or any drug before seeking medical advice from your doctor, healthcare provider, or pharmacist first. To do so may result in serious consequences or side effects.

Severe Interactions of Venlafaxine include:

• iobenguane I 123
• isocarboxazid
• phenelzine
• procarbazine
• selegiline
• tranylcypromine

Venlafaxine has serious interactions with at least 69 different drugs.

Venlafaxine has moderate interactions with at least 172 different drugs.

Venlafaxine has mild interactions with at least 35 different drugs.

Venlafaxine has mild interactions with at least 65 different drugs.
This document does not contain all possible interactions from the use of this medication. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Warnings

• In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (younger than 24 years) taking antidepressants for major depressive disorders and other psychiatric illnesses.
• This increase was not seen in patients aged older than 24 years; a slight decrease in suicidal thinking was seen in adults older than 65 years.
• Not FDA approved for children; in children and young adults; benefits of taking antidepressants must be weighed against risks.
• Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies; this should be done during the initial 1-2 months of therapy and dosage adjustments.
• The patient's family should communicate any abrupt behavioral changes to a healthcare provider.
• Worsening behavior and suicidal tendencies that are not part of presenting symptoms may necessitate discontinuance of therapy.
• Not FDA approved for the treatment of bipolar depression.
• This medication contains venlafaxine. Do not take Effexor or Effexor XR if you are allergic to venlafaxine or any ingredients contained in this drug.

Contraindications

• Hypersensitivity
• Co-administration with serotonergic drugs
  • Co-administration with monoamine oxidase inhibitors (MAOIs)
  • Concomitant MAOIs administration within 14 days before initiating venlafaxine or within 7 days after discontinuing venlafaxine
  • Initiation of venlafaxine inpatient being treated with linezolid or IV methylene blue

Effects of Drug Abuse

• No information provided

Short-Term Effects

• See "What Are Side Effects Associated with Using Venlafaxine (Effexor, Effexor XR)?"

Long-Term Effects

• See "What Are Side Effects Associated with Using Venlafaxine (Effexor, Effexor XR)?"

Cautions

• Risk of mydriasis; may trigger angle closure attack in patients with angle-closure glaucoma with anatomically narrow angles without a patent iridectomy.
• Use caution in bipolar mania, history of seizures, and cardiovascular disease.
• May precipitate mania or hypomania episodes in patients with bipolar disorder; avoid monotherapy in bipolar disorder; screen patients presenting with depressive symptoms for bipolar disorder.
• Use caution in hepatic or renal impairment.
• Neonates exposed to serotonin-norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs) late in 3rd trimester of pregnancy have developed complications necessitating prolonged hospitalization, respiratory support, and tube feeding.
• Clinical worsening and suicidal ideation may occur despite medication in adolescents and young adults (18-24 years).
• When discontinuing, taper dosage to avoid flulike symptoms.
• May cause an increase in nervousness, anxiety, or insomnia.
• May impair ability to operate heavy machinery; depresses CNS.
• Bone fractures are reported with antidepressant therapy; consider the possibility if the patient experiences bone pain.
• May cause a significant increase in serum cholesterol.
• Dose-dependent anorectic effects and weight loss were reported in children and adult patients.
• Dose-related increase in systolic and diastolic pressure reported.
• Eosinophilic pneumonia and interstitial lung disease were reported.
• SIADH and hyponatremia reported SSRIs.
• Potentially life-threatening serotonin syndrome with SSRIs and SNRIs when used in combination with other serotonergic agents including TCAs, buspirone tryptophan, fentanyl, tramadol, lithium, tryptophan, buspirone, amphetamines,
• St. John's wort, and triptans; symptoms include tremor, myoclonus, diaphoresis, nausea, vomiting, flushing, dizziness, hyperthermia with features resembling neuroleptic malignant syndrome, seizures, rigidity, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma.
• Venlafaxine inpatient being treated with linezolid or IV methylene blue increases the risk of serotonin syndrome; if linezolid or IV methylene blue must be administered, discontinue venlafaxine immediately and monitor for central nervous system (CNS) toxicity; therapy may be resumed 24 hours after last linezolid or methylene blue dose or after 2 weeks of monitoring, whichever comes first.
• SSRIs and SNRIs may impair platelet aggregation and increase the risk of bleeding events, ranging from ecchymosis, hematomas, epistaxis, petechiae, and GI hemorrhage to life-threatening hemorrhage; concomitant use of aspirin,
• NSAIDs, warfarin, other anticoagulants, or other drugs are known to affect platelet function may add to this risk.
• Control hypertension before initiating treatment; monitor blood pressure regularly during treatment.
• Risks of sustained hypertension, hyponatremia, and impeded height and weight in children.
• Drug-laboratory test interactions: False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been observed during venlafaxine therapy because of the lack of specificity of the screening tests.
• May cause or exacerbate sexual dysfunction.

Pregnancy and Lactation

• Use venlafaxine with caution during pregnancy if the benefits outweigh the risks. Animal studies show risk and human studies are not available or neither animal nor human studies are done. Neonates exposed to serotonin-norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs) late in 3rd trimester of pregnancy have developed complications necessitating prolonged hospitalization, respiratory support, and tube feeding.
• Venlafaxine enters milk; breastfeeding is not recommended.