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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Limited Use [what does this mean?]
Generic drug name: venlafaxine (ven la FAX een)
Brand name(s): EFFEXOR XR
GENERIC: available FAMILIES: Other Drugs for Depression, Selective Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

This drug caused harm to developing fetuses in animal studies, including a decrease in birth weight, an increase in still births, and an increase in pup deaths after birth. There is new evidence that when women take this drug in the third trimester of pregnancy, serious complications can arise in their infants’ health immediately after delivery. These complications require prolonged hospitalization, respiratory support, and tube feeding.

Breast-feeding Warning

Venlafaxine and its metabolite are excreted in human milk. Because of the potential for serious adverse reactions in the nursing infant, you should not take this drug while nursing.

Safety Warnings For This Drug [top]


Suicidality and Antidepressant Drugs

Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents and young adults in short-term studies. These studies did not show an increase in the risk of suicidal thoughts and behavior with antidepressant use in patients older than 24 years; there was a reduction in risk with antidepressant use in patients aged 65 and older. In patients of all ages who are started on antidepressant therapy, monitor closely for clinical worsening and emergence of suicidal thoughts and behaviors. Advise families and caregivers of the need for close observation and communication with the prescriber.

Sexual Dysfunction

All of the SSRI antidepressants have been shown to commonly cause sexual dysfunction in both men and women. In a large prospective study of over 6,000 men and women, sexual dysfunction occurred 36–43% of the time, depending on the drug. Types of sexual dysfunction include problems of desire (libido: sexual interest or drive), arousal (erectile function in men, lubrication in women) and release (ejaculation/orgasm in men and orgasm in women). Strategies to cope with this problem include decreasing the dosage to the lowest effective level; a drug holiday for patients in whom compliance is not a problem; if acceptable to the patient and partner, seeing if the sexual dysfunction resolves without further intervention.[1]

Facts About This Drug [top]

Venlafaxine (EFFEXOR XR) is approved by the Food and Drug Administration (FDA) for treating major depression, as well as generalized anxiety disorder, social anxiety disorder and panic disorder. It is a member of the family of drugs called selective serotonin/norepinephrine reuptake inhibitors (SNRIs). Like all other antidepressants, venlafaxine improves, but does not cure, the symptoms of depression. This drug works by blocking the neurotransmitters serotonin and norepinephrine.

We have...

Venlafaxine (EFFEXOR XR) is approved by the Food and Drug Administration (FDA) for treating major depression, as well as generalized anxiety disorder, social anxiety disorder and panic disorder. It is a member of the family of drugs called selective serotonin/norepinephrine reuptake inhibitors (SNRIs). Like all other antidepressants, venlafaxine improves, but does not cure, the symptoms of depression. This drug works by blocking the neurotransmitters serotonin and norepinephrine.

We have designated venlafaxine as Limited Use. For patients who need an antidepressant drug, we recommend trying one of the newer selective serotonin reuptake inhibitors (SSRIs; for example, fluoxetine [PROZAC, SARAFEM]) first, as these are the safest antidepressants. If symptoms do not improve sufficiently with use of an SSRI and remain severe, further treatment with other antidepressants is warranted.


Be Careful Not to Overdose

The therapeutic effects of venlafaxine do not start immediately after beginning treatment. In fact, it takes about two weeks to see improvement and several more weeks to experience the full effect. If improvement is inadequate, the dose can be increased to 150 milligrams (mg) a day, no more frequently than every four days, under the supervision of a physician.

The maximum total daily dose of immediate-release venlafaxine is 375 mg, and the maximum daily dose of extended-release venlafaxine is 225 mg. People with kidney or liver problems and elderly adults should take a lower dose.


Venlafaxine is not recommended for women who are pregnant or breastfeeding or for children younger than 18 years.

In October 2008, Health Canada (an agency similar to the FDA) issued a communication that extended-release venlafaxine overdosage may be associated with an increased risk of death compared with the related SSRIs. This safety information was incorporated into the "Overdosage" section of all Canadian product information for extended-release venlafaxine products.[2]

In 2016, Prescrire International published a review of venlafaxine indicating that the risk of cardiac adverse effects and fatal overdoses is higher with venlafaxine than with other SSRI drugs.[3]

Adverse effects

Some adverse effects of venlafaxine are more likely to occur with higher doses, but these can be minimized by starting with low doses, such as 25 mg a day.[4]

High blood pressure occurs in patients using this drug, so patients should work with their physicians to regularly monitor their blood pressure.

According to the Committee on Safety of Medicines in the United Kingdom, the risk of cardiac adverse effects and toxicity after overdose of venlafaxine is higher than it is with SSRIs.

Venlafaxine was ranked fourth on a list of drugs implicated in causing QT prolongation in Finland between 1981 and 2004.[5] The QTc interval is the length of time it takes the large chambers of the heart (ventricles) to electrically discharge and recharge. A prolongation of the QTc interval can lead to torsades de pointes (heart rhythm disruption) and sudden death.

Prolonged use of this drug can cause a decrease in saliva, which can lead to cavities and other dental problems.

Serotonin syndrome

Serotonin syndrome is a potential danger when taking a combination of migraine-headache drugs called triptans with SNRIs, SSRIs or other drugs that affect serotonin, such as venlafaxine. Serotonin syndrome can be life-threatening and happens when there is an excess of serotonin. This usually occurs when two or more drugs that affect serotonin are taken together.

The symptoms of serotonin syndrome include the following

  • Restlessness
  • Hallucinations
  • Loss of coordination
  • Fast heartbeat
  • Increased body temperature
  • Rapid changes in blood pressure
  • Overactive reflexes
  • Diarrhea
  • Coma
  • Nausea
  • Vomiting[6]

Abnormal bleeding

The product label for venlafaxine includes a precaution that use of the drug with escitalopram (LEXAPRO) may increase the risk of bleeding. Use of aspirin, nonsteroidal anti-inflammatory drugs, warfarin and other anticoagulants with venlafaxine may increase this risk.

Low blood sodium

Venlafaxine also has been associated with cases of clinically significant hyponatremia (low blood sodium). Elderly patients may be at greater risk.

Researchers recommend that elderly patients have their sodium levels checked promptly and regularly when taking venlafaxine. This recommendation is based on a study in patients over the age of 65, in which the author found that low blood sodium developed within the first few days of starting treatment with venlafaxine.[7]

Symptoms of hyponatremia include the following:

  • Headache
  • Difficulty concentrating
  • Memory impairment
  • Confusion
  • Weakness
  • Unsteadiness, which may lead to falls

Symptoms associated with more severe and/or acute cases of hyponatremia have included the following:

  • Hallucination
  • Syncope (dizziness)
  • Seizure
  • Coma
  • Respiratory arrest
  • Death[8]

Antidepressants and pregnancy

On Aug. 9, 2004, Health Canada issued a public advisory warning to Canadians that newborns may be adversely affected when their mothers take an SSRI or other newer antidepressant during the third trimester of pregnancy. Health Canada reported that some newborns whose mothers took these drugs during pregnancy have developed complications at birth requiring prolonged hospitalization, breathing support and tube feeding. The symptoms reported include feeding and breathing difficulties, seizures, muscle rigidity, jitteriness and constant crying. In most cases, the mothers were prescribed newer antidepressants during the third trimester of pregnancy.[9]

In May 2012, Prescrire International published an article on reports that use of venlafaxine during pregnancy was associated with gestational hypertension (high blood pressure during pregnancy).[10]

Recent research also has linked use of SNRIs, including venlafaxine, during early pregnancy to a small increased risk of birth defects, including heart malformations.[11],[12]

Neuroleptic malignant syndrome

In 2009, the FDA updated the product label of antidepressants to warn of potentially life-threatening neuroleptic malignant syndrome (NMS) resulting from use of SSRIs and SNRIs alone or with subsequent use of serotonergic drugs such as triptans, with drugs that make the metabolism of serotonin more difficult or with antipsychotics or other dopamine antagonists.[13]

Symptoms of NMS can include extremely high body temperature (hyperthermia); heavy sweating; fast heart rate; fast respiratory rate; rapidly fluctuating blood pressure; impaired consciousness; tremor; and rigid, stiff muscles.

Other regulatory actions surrounding venlafaxine

2004: In October, the FDA issued a public health advisory requiring manufacturers to add a black-box warning (see "FDA Black-Box Warning" at the top of this profile) to the product label of all antidepressants, including information on suicidal thoughts, agitation and impulsivity. A black-box warning is the strongest warning the FDA can require.

The FDA also required that a Medication Guide be given to patients receiving this drug to advise them of the risks and of precautions that can be taken. Click here to view the venlafaxine Medication Guide.

2006: In January, the FDA updated the product label for the venlafaxine extended-release capsules (EFFEXOR XR) to warn about prolonged periods of high blood pressure in patients using the drug to treat panic disorder.[14]

In July, the FDA issued a public health advisory to warn consumers about the possibility of life-threatening reactions — such as nausea, changes in blood pressure or hallucinations — that may be caused by the interaction of triptans and certain antidepressants, including venlafaxine.

In October, the FDA revised the product label of venlafaxine to highlight information regarding venlafaxine overdose. In post-marketing patient experiences, there have been reports of overdose with venlafaxine, occurring mostly in combination with alcohol and/or other drugs. To reduce the risk of overdose, venlafaxine should be prescribed in the smallest quantity possible and in combination with good patient management.[15]

2007: The FDA announced in May that it would require new warnings concerning the increased risk of suicidal thoughts and behavior in young adults ages 18 to 24 during the first one to two months of treatment with antidepressants. The agency required that the new black-box warnings be printed on the product labels for all antidepressants sold in the United States. The warnings amended an existing black-box warning for children and adolescents.[16]

The FDA-approved product label for antidepressant drugs sold in the United States carries the following statement:

Suicide: The possibility of a suicide attempt is inherent in major depressive disorder and may persist until significant remission occurs. Close supervision of high-risk patients should accompany initial drug therapy. Prescriptions for [Drug X] should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose.

2020: The Medicines and Healthcare products Regulatory Agency (an agency in the United Kingdom similar to the FDA) issued an advisory that SNRI drugs may be associated with a small increased risk of bleeding in women following childbirth when used during the month before delivery.[17]

2023: The FDA updated the drug product label of SNRIs to warn that when these drugs are used in the month before delivery, there is an increased risk of bleeding after giving birth.[18]

Before You Use This Drug [top]

Tell your doctor if you have or have had:

  • allergies
  • blood pressure problems
  • heart, kidney, or liver problems
  • pregnancy or are breast-feeding
  • seizures
  • history of mania

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Do not drink alcohol or use other drugs that can cause drowsiness.
  • Until you know how you react to this drug, do not drive or perform other activities that require alertness.
  • You may feel dizzy when rising from a lying or sitting position. When getting out of bed, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, stay beside the chair until you are sure that you are not dizzy.
  • Use sugarless gum, ice, or saliva substitute if you develop a dry mouth.
  • Have your doctor assess your need to continue taking this drug periodically.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.

How to Use This Drug [top]

  • If you miss a dose and if it is a prompt-release tablet, take it as soon as you remember, unless it is within two hours of the next dose. Do not take double doses. For extended-release tablets, take as soon as possible if remembered the same day. Continue on regular schedule for next dose.
  • Do not share your medications with anyone.
  • Take your drug at the same time(s) each day.
  • Take at regular intervals with food.
  • Swallow extended-release tablets whole.
  • Do not stop taking this drug suddenly, since you could develop signs of withdrawal, such as dizziness, headache, and nausea. Check with your doctor about tapering your dose.
  • Store tablets at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.
  • Tell your doctor immediately if you have skin rash or hives.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

Do not take venlafaxine within 14 days of stopping or starting these monoamine oxidase (MAO) inhibitors: deprenyl, ELDEPRYL, furazolidone, FUROXONE, isocarboxazid, MARPLAN, MATULANE, NARDIL, PARNATE, pheneizine, procarbazine, selegiline, tranylcypromine.

Central nervous system (CNS) depressant drugs, including alcohol, antidepressants, antihistamines, antipsychotics, some blood pressure medications (reserpine, methyldopa, beta-blockers), motion sickness medications, muscle relaxants, narcotics, sedatives, sleeping pills, and tranquilizers.

Other interacting drugs are: cimetidine, COMTAN, entacapone, HALDOL, haloperidol, metoclopramide, MERIDIA, NORVIR, REGLAN, ritonavir, sibutramine, TAGAMET.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • agitation
  • blood pressure increase
  • breathing difficulty
  • chest pain
  • confusion
  • seizures
  • decreased sexual desire or ability
  • depression
  • diarrhea
  • dizziness
  • extreme drowsiness, tiredness, or weakness
  • uncontrolled excitement and activity
  • fainting or lightheadedness
  • fever
  • headache
  • more rapid or pounding heartbeat
  • incoordination
  • itching or skin rash
  • lockjaw
  • menstrual changes
  • mood or mental changes
  • restlessness
  • ringing or buzzing in ears
  • swelling of legs or feet
  • twitching
  • difficulty urinating
  • vision changes
  • abnormal thinking

Call your doctor if these symptoms continue:

  • abnormal dreams
  • anxiety, nervousness
  • constipation
  • diarrhea
  • dry mouth
  • insomnia (trouble sleeping)
  • loss of appetite
  • nausea or vomiting
  • runny or stuffed nose
  • stomach pain
  • taste changes
  • tingling sensation
  • tiredness, weakness, frequent yawning
  • weight loss
  • chills
  • trembling or shaking
  • dizziness
  • heartburn
  • sweating
  • drowsiness

Call your doctor if these symptoms continue after you stop taking the drug:

  • nausea
  • nervousness
  • tiredness or weakness
  • abnormal dreams
  • dizziness
  • dry mouth
  • increased sweating
  • trouble sleeping
  • headache

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood pressure

last reviewed January 1, 2024