Side Effects of Effexor XR: What You Need to Know

Effexor XR (venlafaxine) is a prescription drug that’s used to treat certain mental health conditions, such as major depressive disorder. Effexor XR can cause side effects that range from mild to serious. Examples include weight changes, sweating, and high blood pressure.

Effexor XR is used in adults to treat:

major depressive disorder (commonly called depression)
generalized anxiety disorder
social anxiety disorder
panic disorder

The active ingredient in Effexor XR is venlafaxine. (An active ingredient is what makes a drug work.) The drug comes as an extended-release (XR) capsule, which means it slowly releases the active ingredient over a prolonged period of time.

Keep reading to learn about the common, mild, and serious side effects that Effexor XR can cause. For a general overview of the drug, including details about its uses, see this article.

Some people may experience mild or serious side effects during their Effexor XR treatment. Examples of Effexor XR’s commonly reported side effects include:

nausea
feeling tired
sweating*
constipation
sexual side effects

* To learn more about this side effect, see “Side effects explained” below.

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Effexor XR may cause mild side effects in some people. Examples of mild side effects that have been reported with Effexor XR include:

nausea
feeling tired
sweating*
constipation
dry mouth
unusual dreams
loss of appetite
headache
weight gain or weight loss*

* To learn more about this side effect, see “Side effects explained” below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And do not stop using Effexor XR unless your doctor recommends it.

Effexor XR may cause mild side effects other than the ones listed above. See the Effexor XR prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Effexor XR, visit MedWatch.

In rare cases, some people may develop serious side effects from taking Effexor XR. Serious side effects that have been reported with Effexor XR include:

suicidal thoughts or behaviors*
serotonin syndrome (high level of the chemical serotonin)
sexual side effects, such as erectile dysfunction and irregular ejaculation
high blood pressure†
unusual bleeding
eye problems, such as closed-angle glaucoma
mania or hypomania (both of which cause moments of extremely high excitement and energy)
allergic reaction†‡
low sodium in your blood
seizures
lung problems, such as pneumonia
high cholesterol

If you develop serious side effects while taking Effexor XR, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* Effexor XR has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.
† To learn more about this side effect, see “Side effects explained” below.
‡ An allergic reaction is possible after using Effexor XR. But it’s not clear whether this side effect occurred in studies.

You may experience more side effects in your first week of treatment with Effexor XR. But not everyone will experience side effects, and side effects can be different for each person.

You may be more likely to experience suicidal thoughts and behaviors* during the first week of treatment. If you notice symptoms, be sure to talk with your doctor.

When you first start taking a new medication, your body has to get used to it. So in the first week, you may experience more side effects. It takes about 3 days for Effexor XR to reach a consistent level in your blood. During the time that your body is adjusting, you may have a higher risk for side effects.

Side effects that you experience may also depend on other medical conditions you have or other medications you take. If you have questions about what to expect when you first start taking Effexor XR, talk with your doctor or pharmacist.

* Effexor XR has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.

Get answers to some frequently asked questions about Effexor XR’s side effects.

Are there any long-term side effects of Effexor XR?

Yes, long-term side effects of Effexor XR are possible. Examples include weight gain, weight loss, and eye problems such as closed-angle glaucoma.

It’s possible that taking Effexor XR for a longer period of time may raise your risk for long-term side effects. But this isn’t the case for everyone, as side effects of Effexor XR can vary from person to person.

If you’re concerned about long-term side effects of Effexor XR, talk with your doctor or pharmacist.

Do side effects from Effexor XR vary depending on the strength I take (37.5 mg, 75 mg, or 150 mg)?

It’s possible. You may have an increased risk for side effects if you’re taking a higher dose of Effexor XR. This is because there’s more medication in your body, and it may have a greater effect on you.

Will Effexor XR cause withdrawal symptoms if I stop taking it?

Effexor XR can cause withdrawal symptoms if treatment stops suddenly.

Examples of withdrawal symptoms that may occur if you stop taking Effexor XR include:

agitation or irritability
confusion
dizziness
anxiety
headache
insomnia (trouble sleeping)
seizures

If you’re interested in stopping your Effexor XR treatment, talk with your doctor first. They’ll likely want to decrease your dose slowly to help reduce the risk of withdrawal symptoms.

In most cases, your doctor will decrease your dose by 75 milligrams per week until you’re not taking the drug anymore. But be sure to follow your doctor’s recommendation for decreasing your dose and stopping treatment.

Because some withdrawal symptoms may be serious, you should not stop taking Effexor XR without first talking with your doctor. They can help you safely stop your treatment.

Can side effects occur if I miss a dose of Effexor XR?

Yes, it’s possible that missing a dose of Effexor XR may cause certain side effects, including withdrawal symptoms.

If you miss a dose of Effexor XR, take it as soon as you remember. But if it’s almost time for your next dose, skip your missed dose and take your next dose on your regular schedule. You should not take two doses of Effexor XR to make up for a missed dose. Doing so could raise your risk for side effects.

How long do side effects from Effexor XR last?

It depends. Some side effects, such as nausea, may occur when you first start taking Effexor XR but may go away after you take it for a while. Other side effects, including decreased appetite and changes in weight, may last throughout your treatment.

If you’re concerned about certain side effects of Effexor XR, talk with your doctor. They can discuss your risk for these side effects and how long they may last if you do experience them. Your doctor may also be able to treat your side effects so they don’t last as long.

Learn more about some of the side effects Effexor XR may cause.

Weight gain or weight loss

Weight gain or weight loss can occur in people taking Effexor XR. But these were not common side effects reported in studies of Effexor XR.

What might help

If you’re concerned about any unexpected weight gain or weight loss you experience while taking Effexor XR, talk with your doctor. They can help determine what your next steps should be.

Sweating

You may experience sweating during your Effexor XR treatment. Sweating was one of the most common side effects that people taking Effexor XR reported in studies.

What might help

If you’re sweating more than usual while taking Effexor XR and it’s bothersome to you, talk with your doctor. They may be able to recommend ways to decrease this side effect. In some cases, they may recommend a different medication to treat your mental health condition.

Suicidal thoughts and behaviors in children and young adults

Effexor XR has a boxed warning for the risk of suicidal thoughts and behaviors in children and in young adults (ages 18 to 24 years). A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

All antidepressant drugs carry this boxed warning about suicidal thoughts and behaviors. These side effects can occur within the first few months of starting treatment or whenever the dose is increased or decreased.

It’s important to note that Effexor XR is not approved for anyone younger than 18 years old.

What might help

It’s important that you tell your doctor if you notice any new or worsening symptoms of depression or suicidal thoughts or behavior. These may include:

suicidal thoughts or suicide attempts
violence or aggression
anxiety or panic attacks
feeling restless or irritable
insomnia (trouble sleeping)
changes in behavior or mood

If you notice any of these symptoms, talk with your doctor. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

If you’re a young adult taking Effexor XR, your doctor will likely monitor you more closely during treatment for any symptoms of depression and suicidal thoughts or behaviors.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

Call the 988 Suicide and Crisis Lifeline at 988.
Text HOME to the Crisis Textline at 741741.
Not in the United States? Find a helpline in your country with Befrienders Worldwide.
Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

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High blood pressure

Effexor may increase your blood pressure. In studies, some people who didn’t already have high blood pressure developed the condition after starting treatment with Effexor XR.

If you already have high blood pressure, Effexor XR may make it worse.

What might help

Before you start taking Effexor XR, tell your doctor about any blood pressure concerns you have or if you’re taking medication to lower your blood pressure.

If you have untreated high blood pressure, your doctor will likely want to treat it before starting your Effexor XR treatment. This is because the drug can also increase your blood pressure, which may be unsafe if your blood pressure is already high.

Your doctor will also check and monitor your blood pressure throughout your treatment.

Allergic reaction

Like most drugs, Effexor XR can cause an allergic reaction in some people. But it’s not clear whether this side effect occurred in studies.

Symptoms can be mild or serious and can include:

skin rash
itchiness
flushing (temporary warmth, redness, or deepening of skin color)
swelling under your skin, typically in your eyelids, lips, hands, or feet
swelling of your mouth, tongue, or throat, which can make it hard to breathe

Allergic reactions can also affect the eyes. It’s important that you tell your doctor if you notice any problems with your eyes. Symptoms may include:

changes in your vision
eye pain
redness, discoloration, or swelling in or around your eye

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter antihistamine that you swallow, such as Benadryl (diphenhydramine), or a product that you apply to your skin, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms you had a mild allergic reaction to Effexor XR, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Effexor XR, they may have you switch to a different treatment.

what dose of drug you were taking when you had the side effect
how soon after starting that dose you had the side effect
what your symptoms were from the side effect
how it affected your daily activities
what other medications you were also taking
any other information you feel is important

Before you start taking Effexor XR, talk with your doctor about any medical conditions you have or any medications you take. They can determine if this medication may be a safe treatment option for you.

Details about this drug’s warnings are below.

Boxed warning: Suicidal thoughts and behaviors in children and young adults

Effexor XR has a boxed warning for suicidal thoughts and behaviors in children and in young adults (ages 18 to 24 years). A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

If you’re a young adult taking Effexor XR, your doctor will likely monitor you more closely during treatment for any symptoms of depression and suicidal thoughts or behaviors.

It’s important to note that Effexor XR is not approved for anyone younger than 18 years old.

To learn more, see the “Side effects explained” section above.

Other warnings

Effexor XR may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Effexor XR. The list below includes factors to consider.

High blood pressure or other heart problems. Before taking Effexor XR, tell your doctor if you have high blood pressure. This drug may cause your blood pressure to increase even more. Your doctor will check your blood pressure before you start treatment. If it’s not well managed, your doctor will likely recommend treating your high blood pressure before you start taking Effexor XR. Even if your blood pressure is well managed, your doctor may want to monitor you more closely during your Effexor XR treatment. This is to make sure your blood pressure doesn’t get too high.

Allergic reaction. If you’ve had an allergic reaction to Effexor XR or any of its ingredients, you should not take Effexor XR. Ask your doctor what other medications are better options for you.

Bipolar disorder or mania. Effexor XR may make your symptoms of bipolar disorder or mania worse. If you have one of these conditions, your doctor may recommend a different medication to treat your condition, or they may monitor you more closely during your treatment.

Glaucoma. Effexor XR may cause an eye condition called closed-angle glaucoma. If you already have closed-angle glaucoma, Effexor XR may make your condition worse. Before taking Effexor XR, talk with your doctor about any eye conditions you have.

Liver problems. Effexor XR may cause elevated liver enzymes, which may be a sign of a liver condition. If you already have a liver problem, Effexor XR may make your condition worse. Before you start treatment with Effexor XR, tell your doctor about any liver conditions you have.

Alcohol and Effexor XR

You should not drink alcohol while taking Effexor XR. Alcohol may raise your risk for certain side effects from Effexor XR.

If you drink and have concerns about avoiding alcohol during your Effexor XR treatment, talk with your doctor.

Pregnancy and breastfeeding while taking Effexor XR

Below are details about using Effexor XR during pregnancy or while breastfeeding.

Pregnancy

It’s not known if Effexor XR is safe to take during pregnancy. If you’re pregnant or planning to become pregnant, talk with your doctor before taking Effexor XR.

Breastfeeding

Taking Effexor XR while breastfeeding is not recommended. Effexor XR passes into breast milk, and it may affect a child who is breastfed. If you’re currently breastfeeding or planning to breastfeed, talk with your doctor about your options.

Effexor XR may be an effective treatment for certain mental health conditions. But some people may experience side effects with this drug. Most side effects are mild, but some may be serious.

It’s important to discuss potential side effects with your doctor before taking Effexor XR so you know what to watch for. Here are some questions you may want to ask your doctor:

How should I treat any side effects that I experience?
Do I have a higher risk for side effects based on my other medical conditions?
What should I do if I become pregnant while taking Effexor XR?

To get information on different conditions and tips for improving your health, subscribe to any of Austra Health’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

Q:

If I’m taking a monoamine oxidase inhibitor (MAOI), how long should I wait between stopping the MAOI and starting treatment with Effexor XR so that I don’t experience side effects?

A:

A: If you’re taking Effexor XR with an MAOI such as the antidepressant Nardil (phenelzine) or the antibiotic Zyvox (linezolid), you should not take these medications within 7 days of stopping Effexor XR unless your doctor recommends it. It’s also important that you stop taking an MAOI at least 2 weeks before starting your Effexor XR treatment.

Before you stop taking any medications, be sure to check with your doctor first.

The Austra Health Pharmacist Team Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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Disclaimer: Austra Health has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

Last medically reviewed on October 9, 2022

How we reviewed this article:

Austra Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Effexor XR (venlafaxine extended-release) capsules, for oral use. (2022).
accessdata.fda.gov/drugsatfda_docs/label/2022/020699s112lbl.pdf

Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

Side Effects of Effexor XR: What You Need to Know

Are there any long-term side effects of Effexor XR?

Do side effects from Effexor XR vary depending on the strength I take (37.5 mg, 75 mg, or 150 mg)?

Will Effexor XR cause withdrawal symptoms if I stop taking it?

Can side effects occur if I miss a dose of Effexor XR?