If you have depression or a certain kind of anxiety, you may be interested in learning more about venlafaxine. It’s a generic prescription drug used to help treat the following conditions in adults:

Venlafaxine comes as an extended-release (ER)* capsule that you swallow.

It also comes in ER and immediate-release (IR)† tablets that you swallow. But the tablet forms of venlafaxine are not covered in this article.

Venlafaxine is also called venlafaxine hydrochloride (HCl). The drug may be used as a long-term treatment.

This article describes venlafaxine’s side effects. For more information about venlafaxine, including details about its uses, see this in-depth article.

* ER means the drug slowly releases the active ingredient over a long period of time. (An active ingredient is what makes a drug work.)
† IR means the drug releases the active ingredient as soon as you take it.

Some people may experience mild to serious side effects during their venlafaxine treatment. Examples of the drug’s commonly reported side effects include:

  • sweating
  • sleepiness
  • dry mouth
  • digestive problems, such as
    • nausea*
    • constipation
    • loss of appetite
  • sexual side effects

Read on to learn about other possible mild and serious side effects of venlafaxine.

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

Some people may have mild side effects while taking venlafaxine. Examples that have been reported with this drug include:

* To learn more about this side effect, see the “Side effects explained” section below.
† To learn more about this side effect, see the “Venlafaxine and weight gain or weight loss” section below.
‡ An allergic reaction is possible after using venlafaxine. This side effect wasn’t reported in studies, but has been reported since the drug became available as a prescription.

In most cases, these side effects should be temporary. And some may be easily managed. But if you have any symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop taking venlafaxine unless your doctor recommends it.

Venlafaxine may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

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

Serious side effects can happen with venlafaxine, but most of them are rare.

Serious side effects that have been reported with this drug include:

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

* Venlafaxine 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 the “Side effects explained” section below.
‡ To learn more about this side effect, see the “Venlafaxine sexual side effects” section below.
§ An allergic reaction is possible after using venlafaxine. This side effect wasn’t reported in studies but has been reported since the drug became available as a prescription.

Help is out there

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

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.

Venlafaxine is not approved for use in children under the age of 18 years. But venlafaxine has a boxed warning for the increased risk of suicidal thoughts and behaviors in children. 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.

This risk also affects adults ages 24 years and younger. For details, see the “Side effects explained” section below.

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

Do venlafaxine’s side effects vary based on which strength (37.5 mg, 75 mg, 150 mg) or dosage I’m taking (such as 300 mg per day)?

It’s possible for side effects from venlafaxine to vary based on the strength or dose you’re prescribed. For example, in studies of venlafaxine, greater increases in blood pressure occurred at higher doses of the drug.

If you have more questions about your risk of side effects based on your venlafaxine strength or dose, talk with your doctor.

Does stopping venlafaxine cause discontinuation syndrome (withdrawal symptoms)?

Yes, suddenly stopping venlafaxine can lead to withdrawal symptoms. These are side effects that can happen when you suddenly stop taking a drug your body was used to having.

Below are possible withdrawal symptoms of venlafaxine:

To reduce your risk of withdrawal symptoms, it’s important that you do not stop taking venlafaxine unless your doctor advises you to do so. If they do, they’ll instruct you on how to lower your dosage slowly over time before you stop it.

If you have other questions about withdrawal and venlafaxine, talk with your doctor or pharmacist.

Can venlafaxine cause long-term side effects?

Yes, you may have long-term side effects with venlafaxine. But the length of time that side effects from venlafaxine last can vary from person to person.

Most side effects of this drug are expected to ease within hours to days of taking your first dose. In rare cases, side effects of venlafaxine may last longer.

For example, sexual side effects* from venlafaxine could last for several weeks or months after you stop taking the drug.

For more details about what to expect with venlafaxine treatment, talk with your doctor.

* To learn more about this side effect, see the “Sexual side effects” section below.

Does venlafaxine cause joint pain or muscle pain?

Joint pain and muscle pain were not reported as side effects in studies of venlafaxine.

But muscle pain can be a symptom of rhabdomyolysis (a type of severe muscle damage). Rhabdomyolysis wasn’t reported in studies of venlafaxine, but has been reported since the drug became available as a prescription.

Other symptoms of rhabdomyolysis can include:

If you have muscle pain or other symptoms of rhabdomyolysis with venlafaxine, tell your doctor right away. They’ll tell you how to manage this side effect if it happens.

Weight gain and weight loss were less common side effects in studies of venlafaxine.

Keep in mind that weight changes can occur with depression and anxiety. So you may experience weight gain or weight loss because of the condition you’re using the drug to treat.

In addition, the digestive side effects of venlafaxine may lead to weight loss. These include nausea, loss of appetite, and diarrhea. If you have these side effects with venlafaxine, you may notice weight loss.

If you’re concerned about weight gain or weight loss with venlafaxine, talk with your doctor. They can suggest ways to maintain a healthy weight.

Sexual side effects were common in studies of venlafaxine. Below are examples that have been reported with this drug:

It’s important to remember that depression and anxiety may also affect you sexually. Venlafaxine is used to treat these conditions. So it may be difficult to tell whether these side effects are related to the drug or the condition you’re taking the drug to treat.

If you have sexual side effects while taking venlafaxine, talk with your doctor. They can help you figure out whether the side effects are from venlafaxine or the condition it’s treating.

Learn more about some of the side effects venlafaxine may cause.

Urinary side effects

Urinary side effects were not common in studies of venlafaxine. But examples of urinary side effects that may occur include:

What might help

If you have urinary side effects with venlafaxine, talk with your doctor. They can recommend ways to manage these side effects. They can also recommend whether a treatment option other than venlafaxine might be better for you.

Nausea

Nausea was one of the most common side effects in studies of venlafaxine. (With nausea, you may have belly discomfort or feel as though you need to vomit.)

What might help

Nausea with venlafaxine is usually temporary. This side effect may ease as your body gets used to the medication. It should go away after you’ve taken the drug for a few days to weeks. But if you have bothersome or long-lasting nausea with venlafaxine, talk with your doctor. They can suggest ways to ease it, such as taking the drug with food.

Headache

Headache was a less common side effect in studies of venlafaxine. (With headache, you may feel pain or discomfort in your head or face.)

What might help

If you have bothersome headaches with venlafaxine, talk with your doctor. They can recommend ways to relieve your symptoms. For example, they may suggest you take an over-the-counter (OTC) pain reliever, such as acetaminophen (Tylenol).

Keep in mind that certain OTC pain relievers can increase your risk of bleeding as a side effect of venlafaxine. These include nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin) and naproxen (Aleve).

Increased risk of suicidal thoughts and behaviors

Venlafaxine has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Antidepressants, such as venlafaxine, may increase the risk of suicidal thoughts and behaviors in certain people. This includes children and adults ages 24 years and younger. But keep in mind that venlafaxine is not approved for use in children under the age of 18 years.

While you’re taking venlafaxine, watch for new or worsened anxiety or depression. Also watch for changes in mood, such as agitation, irritability, and anger. These can be signs of an increased risk of suicidal thoughts or behaviors.

Be sure to watch especially close for the above changes during your first few months of treatment and after any dosage change.

What might help

If you have unusual changes in mood or behaviors with venlafaxine, tell your doctor right away. They may adjust your treatment plan or prescribe a different medication for your condition.

Allergic reaction

Like most drugs, Venlafaxine can cause an allergic reaction in some people. This side effect wasn’t reported in studies, but has been reported since the drug became available as a prescription.

Symptoms can be mild to serious and can include:

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

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 a treatment to manage your symptoms. Examples include:

  • an antihistamine you take by mouth, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to venlafaxine, they’ll decide if you should continue taking 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’ve had a serious allergic reaction to venlafaxine, they may have you switch to a different treatment.

Keeping track of side effects

During your venlafaxine treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

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

Keeping notes and sharing them with your doctor will help them learn more about how venlafaxine affects you. They can then use this information to adjust your treatment plan if needed.

Below are warnings for venlafaxine.

Boxed warning: Increased risk of suicidal thoughts and behaviors in certain people

Venlafaxine has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

This risk affects children and adults ages 24 years and younger. But keep in mind that venlafaxine is not approved for use in children under the age of 18 years.

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

Other warnings

Venlafaxine may not be right for you if you have certain medical conditions. This is known as a drug-condition interaction. Other factors may also affect whether Venlafaxine is a good treatment option for you. Talk with your doctor about your health history before starting this drug. Factors to consider include those described below.

Narrow eye angles. Before starting treatment with venlafaxine, tell your doctor if you have narrow eye angles. The drug can increase the risk of a glaucoma attack in people with this condition. (With a glaucoma attack, you have a sudden increase in eye pressure that cause severe eye pain and loss of vision.)

Before starting venlafaxine, your doctor may recommend you have an eye exam to check for narrow eye angles. If you have this condition, your doctor may prescribe a drug other than venlafaxine for you.

Bipolar disorder. Venlafaxine may cause mania or hypomania (episodes of high energy and excitement that are typically related to bipolar disorder). Before taking venlafaxine, tell your doctor if you have bipolar disorder. They may prescribe a drug other than venlafaxine for you.

High blood pressure. If you have high blood pressure, tell your doctor before starting venlafaxine. This drug may increase your blood pressure, which could worsen the high blood pressure you already have. Your doctor will likely treat your high blood pressure before having you start venlafaxine.

Heart problems. Venlafaxine may cause heart-related side effects, such as increased heart rate. If you have heart disease or have had a heart attack or stroke, talk with your doctor before starting venlafaxine. They can determine if this drug is safe for you.

Liver or kidney problems. Before taking venlafaxine, tell your doctor if you have liver or kidney problems. Examples include liver failure and kidney failure. These conditions could cause venlafaxine to build up in your body, which could increase your risk of side effects from the drug.

If you have liver or kidney problems, your doctor can tell you if it’s safe to take venlafaxine. If they tell you it’s safe, they may prescribe you a lower dosage of the drug than usual.

Seizure. Venlafaxine may cause seizures. If you already have seizures before taking the drug, you may be at a greater risk of them during treatment with this drug.

Before starting venlafaxine, talk with your doctor about any seizures you’ve had. They can tell you whether this drug is the right treatment option for you.

Allergic reaction. If you’ve had an allergic reaction to venlafaxine or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other medications that might be better options for you.

Alcohol and venlafaxine

You should not take venlafaxine with alcohol. Drinking alcohol while taking this drug could increase your risk of overdose with venlafaxine.

If you drink alcohol, talk with your doctor before starting venlafaxine treatment. They can recommend safe ways to stop drinking. Or they may prescribe a different medication for you instead.

Pregnancy and breastfeeding while taking venlafaxine

It’s not known whether venlafaxine is safe to take during pregnancy or while breastfeeding. Studies have shown that the drug passes into breast milk, but it’s not known to cause side effects in a breastfed child.

If you’re pregnant, breastfeeding, or plan to be either, talk with your doctor before starting venlafaxine. They can discuss with you the risks and benefits of using this medication during these times.

If you take venlafaxine while pregnant, consider enrolling in the National Pregnancy Registry for Antidepressants. This registry collects information about what happens when an antidepressant, such as venlafaxine, is used during pregnancy. This helps researchers better understand the risks of using the drug while pregnant.

To enroll in this registry, talk with your doctor. You can also visit the registry’s site or call 844-405-6185.

Like most drugs, venlafaxine can cause side effects. In most cases these are mild, but serious side effects are possible. If you have questions about side effects this drug can cause, talk with your doctor.

Examples of questions you may want to ask to feel more comfortable about venlafaxine treatment include:

  • How do the side effects of venlafaxine compare with other medications that treat my condition?
  • If I have side effects from this drug, will I need to stop taking it?
  • Do I have any health conditions that increase my risk of side effects from venlafaxine?

You can also ask your doctor about Effexor XR, which is the brand-name version of venlafaxine. A generic drug and its brand-name version are expected to have the same side effects because they contain the same active ingredient. (An active ingredient is what makes a drug work.)

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Disclaimer: Healthline 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.