Effexor (Venlafaxine) Side Effects: Common, Severe, & Rare

What Is Effexor (Venlafaxine)?

Effexor (venlafaxine) is FDA-approved for the treatment of depression, anxiety disorders, and other mental health conditions.¹ Effexor belongs to the serotonin and norepinephrine reuptake inhibitors (SNRIs) class of drugs which work by regulating the reabsorption of serotonin and norepinephrine in the brain. This helps to improve one’s mood and emotional well-being, thus relieving symptoms of anxiety or depression.

Effexor is mainly prescribed to those with major depressive disorder (MDD) and generalized anxiety disorder (GAD), as studies suggest the drug is both effective and well-tolerated in these cases.^3,5 Doctors also prescribe Effexor for anxiety disorders, such as social a

nxiety disorder and panic disorder. SRNIs work similarly to SSRIs. However, while SSRIs block only the reuptake of serotonin, Effexor, an SNRI, blocks the reabsorption of both serotonin and norepinephrine.

In some cases, Effexor may be prescribed off-label (not FDA-approved) for use in the treatment of post-traumatic stress disorder (PTSD), premenstrual dysphoric disorder (PMDD), and obsessive-compulsive disorder (OCD).² The medication should only be taken as prescribed by a licensed physician.

Side Effects of Effexor

Side effects are common within the first and second weeks of Effexor treatment. However, the severity and frequency of side effects depend on several factors, including one’s age, current or past health conditions, and the type of condition being treated.

Common side effects, including nausea and vomiting, usually do not require immediate medical attention. Should more severe reactions occur, such as persistent headaches or drowsiness, it may be necessary to seek medical guidance. One’s age and preexisting medical conditions can contribute to the severity of side effects. Additionally, it is important to note that Effexor can have interactions with other substances, which can result in overdose, organ failure, or sudden death.

Common Side Effects

Some side effects of Effexor are mild. Sexual side effects from Lexapro may occur for some, as well as other discomforts. For some people, these effects may go away after one or two weeks, but they often persist for as long as a person takes the medication. However, if the side effects worsen, talk to your doctor as soon as possible.

Common side effects of Effexor may include:¹

• Dry mouth
• Constipation or diarrhea
• Sexual problems
• Sleeping problems
• Appetite issues
• Headaches
• Sweating
• Nausea or vomiting
• Shaking
• Weight changes
• Dizziness
• Drowsiness
• Indigestion
• Abnormal dreams

Severe Side Effects

Sometimes, severe side effects of Effexor can occur, making it difficult for one to function. It is important to seek immediate medical attention if this occurs, as it can be life-threatening. Severity of side effects depends greatly on a person’s age and medical history, as well as any interaction between another substance and Effexor. Therefore, it is important to understand which substances should be avoided when taking this medication.

Severe side effects of Effexor that may require immediate medical attention include:¹

• Serotonin syndrome: Effexor can create serotonin build-up in the body, increasing the risk of serotonin syndrome.
• Discontinuation syndrome: Abruptly stopping Effexor without proper guidance increases the risk of Effexor withdrawal.
• Manic episodes: Patients with bipolar disorder are at increased risk of experiencing manic episodes when taking Effexor.
• Sexual dysfunction: Effexor can result in sexual dysfunction such as ejaculatory delay in men or decreased libido and orgasm in women.
• Irregular heartbeat: Effexor can increase systolic and diastolic blood pressure, increasing hypertension risk.
• Suicidal thoughts: Effexor has been associated with increased risk of suicidal thoughts and behaviors in children and young adults.
• Increased bleeding: Effexor increases the risk of excessive bleeding as the drug interferes with the body’s clotting process.
• Angle-closure glaucoma: Effexor can lead to pupil dilation and narrowing of the eyes’ angles, increasing the risk of angle-closure glaucoma.
• Seizure: Patients with seizure disorders may experience episodic seizures while on Effexor medication.

Rare Side Effects

While much research has been conducted to identify common and severe side effects, there is still the possibility that rare adverse reactions to Effexor may occur. These include rash and muscle stiffness. However, few people have experienced these side effects, meaning they are generally not considered to be a threat. Discuss the risks associated with Effexor with a doctor about taking the medication.

Rare side effects of Effexor may include:¹

• Irritability
• Skin rash
• Menstrual changes
• Severe muscle stiffness
• Uncommon pale skin
• Agitation

Allergic Reactions

Allergic reactions to Effexor are possible, especially if patients have a history of allergic reactions to other antidepressants. Side effects include difficulty breathing and swelling. Seek medical attention immediately if symptoms of an allergic reaction occur, as these can be life-threatening.

Allergic reactions to Effexor may include:³

• Breathing problems
• Rash/hives
• Swelling
• Swollen tongue

Interactions With Effexor

Taking certain medications, herbs, or supplements alongside Effexor can change how Effexor works in your body or increase the risk for serious side effects. This article does not consider all the possible interactions. Please let your doctor, psychiatrists, and pharmacists know about all the products you currently use, such as prescription medication, nonprescription drugs, and herbal supplements. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.

While many antidepressants work in the same way, they each have different chemical structures. Because of this, they produce varying side effects in patients. Therefore, it is important not to mix Effexor with other antidepressants, as this can worsen the side effects of either or both medications. Moreover, combining Effexor with substances such as alcohol can result in similar reactions. Discuss these risks with a doctor before starting Effexor treatment.

Substances to avoid while on Effexor include:^1,4

• St. John’s Wort: St John’s wort is an herbal remedy for depression that, when taken with Effexor, increases the risk of side effects.
• NSAIDs: Taking Effexor with NSAIDs increases the risk of bleeding or bruising.
• Other SNRIs: Combining Effexor with other SNRIs can worsen the side effects of each substance and possibly result in overdose.
• Alcohol: Mixing alcohol with Effexor can trigger or worsen the side effects of either substance.
• Migraine medications: The interaction between Effexor and migraine drugs increases serotonin syndrome risk.
• Blood thinners: Combining Effexor with blood thinners increases the risk of excessive bleeding as Effexor interferes with the blood clotting process.
• MAOIs: Using Effexor with or within 14 days of stopping MAOIs increases the risk of serotonin syndrome.

This is not a comprehensive list of possible interactions. You should speak with your doctor or pharmacist about any prescription or over-the-counter medications, herbs, or supplements that you take before starting Effexor.

Who Experiences Side Effects More?

The severity of side effects range from person to person. One’s age and preexisting health conditions can contribute to the likelihood of experiencing adverse effects. If you are concerned about these risks, share them with your doctor before taking Effexor.

Effexor Side Effects in Women

Effexor may result in adverse effects for both pregnant and breastfeeding women. Mothers taking Effexor while breastfeeding may expose their babies to the drug through breast milk contamination. Effexor may result in birth defects in unborn infants, including heart and brain abnormalities.¹

Effexor Side Effects in Children

Effexor is an antidepressant prescribed to adults for the treatment of depression and anxiety disorders. The medication has not been approved for children as its safety and effectiveness have not been established. Effexor increases the risk of suicidal thoughts and behaviors in younger populations.¹

Withdrawal Symptoms From Effexor

Effexor is only available on prescription and should be taken as prescribed by a doctor. Stopping the medication without proper guidance can lead to Effexor withdrawal. This occurs due to an imbalance of serotonin and norepinephrine in the brain, triggering side effects of the drug.¹

Taking Effexor for extended periods can result in cognitive dependence on the substance. This may lead to medication misuse and further dependency. In the case of withdrawal symptoms or dependency, a doctor can offer alternatives or a tapering dose.

Questions to Ask Your Health Team

If you are considering Effexor as a part of your treatment plan, discuss both the benefits and risks of the medication with a physician. If Effexor is not a suitable option for you, your doctor can recommend an alternative.

Questions to ask your care team about Effexor include:

• Are there risks involved with off-label Effexor treatment?
• How long will it take for me to adjust to Effexor?
• Am I at risk for more severe symptoms if I am already taking other anxiety/depression medications?
• Will a previous history of addiction make me more susceptible to dependency?
• What is the best dose of Effexor to ensure fewer side effects?
• Are there substances I am taking that could interact with Effexor?
• When should I reach out to you about side effects?
• Should I tell my therapist I am taking this medication?
• How often should I come in for checkups while on Effexor?
• Effexor is not working for me. What should I do?
• How do other types of antidepressants compare, such as considering Effexor vs Lexapro?

Final Thoughts

Effexor can be an effective part of a person’s anxiety or depression treatment plan. However, taking the medication can result in side effects that range in severity. Because of this, be sure to discuss your current and past medical history with your physician, and disclose any substances you are considering or currently taking. This can help reduce the risk for experiencing severe adverse reactions to the medication.