Pristiq is a serotonin-norepinephrine reuptake inhibitor (SNRI) used to treat major depressive disorder in adults. Common side effects include nausea, dizziness, insomnia, sweating, sexual issues, weight loss, constipation, fatigue, and dry mouth. Less common side effects include chills, feeling jittery, somnolence, abnormal dreams, and vision problems. Other less common side effects include high blood pressure, tremor, and hot flashes.
What Is Pristiq?
Pristiq is a serotonin-norepinephrine reuptake inhibitor (SNRI) for major depressive disorder. It contains the active ingredient, desvenlafaxine. Pristiq is a brand-name medication while it is also available as generic desvenlafaxine.1 It affects serotonin and norepinephrine levels in the brain to potentially enhance your mood.2 The difference between a selective serotonin reuptake inhibitor (SSRI) vs an SNRI is that SSRIs only affect serotonin and SNRIs impact both serotonin and norepinephrine. Non-FDA-approved uses, also known as off-label uses, of Pristiq may include general anxiety disorder (GAD), social anxiety, panic disorder (PD), post-traumatic stress disorder (PTSD), and migraines. Doctors may prescribe a medication off-label if they believe it can be beneficial based on their professional opinion.
Common Side Effects of Pristiq
Pristiq commonly causes nausea, dizziness, insomnia, decreased appetite, constipation, dry mouth, sweating, and sexual issues. 2 It can also cause fatigue, somnolence, and anxiety. Less common side effects include abnormal dreams, jitteriness, burning or prickling sensations, and tremor. Side effects that can be serious that you should seek medical attention for are abnormal vision or pupil dilation, high blood pressure, and continuous vomiting.
Common side effects of Pristiq can include:2
- Nausea
- Dry mouth
- Constipation
- Vomiting
- Fatigue
- Dizziness
- Insomnia
- Sweating
- Inability to have an orgasm
- Low libido
Severe Side Effects of Pristiq
Severe side effects from Pristiq include ones that are possible with nearly any serotonin agent, such as a risk of suicidal ideation and serotonin syndrome. 2 Pristiq can also risk activation of mania or hypomania, and should not be taken if you also have bipolar disorder. Also, your blood pressure should be controlled and you should not take Pristiq if you also have glaucoma or lung disease. These side effects are serious and require medical attention.
Severe side effects of Pristiq can include:2
- Serotonin syndrome
- Seizures in people who have seizure disorders
- Risk of suicidal thoughts in certain people*
- High blood pressure
- Abnormal bleeding
- Angle-closure glaucoma in certain people who have eye issues
- Activation of mania or hypomania in people who have bipolar disorder
- Low sodium (salt) levels
- Lung disorders including interstitial lung disease and eosinophilic pneumonia
*Pristiq has a black box warning for this side effect. This is the most serious warning from the FDA.
Side effects are different for everyone. The most common side effects include nausea, dizziness, insomnia, sexual issues, constipation, dry mouth, and sweating.2 This list may not include every potential side effect, and some can be rare but serious. Speak with their doctor to ensure that you know all the potential side effects before taking Pristiq.
Allergic Reactions
A severe allergic reaction to Pristiq is similar to a reaction you could have to any medication. If you have an anaphylactic reaction, immediate medical attention is required for these symptoms. Symptoms of an allergic reaction include hives, facial swelling, dizziness, difficulty breathing or speaking, anxiousness or confusion, or a fast, irregular heartbeat.
Symptoms of an allergic reaction can include:
- Swelling
- Trouble breathing or speaking
- Fast and irregular heartbeat
- Anxiousness or confusion
- Lightheadedness, dizziness, or fainting
- Wheezing
- Clammy skin
- Hives
If you do experience an allergic reaction, talk to your doctor or pharmacist immediately. If you experience an anaphylactic reaction, such as difficulty breathing, go to the nearest emergency room. Certain SNRIs should not be used if you are allergic to Pristiq, such as Effexor since it is very similar. However, you may be able to try other SNRIs. You should talk with your prescriber before starting any new antidepressant if you have or do experience an allergic medication to any antidepressants.3
Interactions With Pristiq
Some herbal supplements, substances, and medications, if taken together with Pristiq, can risk serotonin syndrome, a rare but serious side effect. Also, Pristiq is broken down by the same enzymes as some substances and medications and can increase other substances’ absorption. There may also be interactions with Pristiq and substances having similar effects on the body, which increases the risk of side effects.
Substances you should avoid while taking Pristiq include:2
- St John’s Wort: St. John’s Wort may act as strongly as other antidepressants. Therefore, it is highly recommended to not take it with SNRIs.
- Other antidepressants, including MAOIs: Taking Pristiq with other antidepressants can risk serotonin syndrome. Taking a certain type of antidepressant known as an MAOI (monoamine oxidase inhibitor) is contraindicated with Pristiq and you will need to work with your prescriber to ensure you stop taking an MAOI for a certain amount of time before starting Pristiq.
- Alcohol: Alcohol and Pristiq together may increase your risk of seizures, GI bleeds, serotonin syndrome, coma, and death.
- Tryptophan: Large amounts of foods high in tryptophan, such as aged cheese,
- beer, and chocolate, can risk serotonin syndrome.
- Blood thinners: Pristiq can risk bleeding, so medicines like Aleve, aspirin, ibuprofen, warfarin, and Xarelto should not be taken with Pristiq.
Who Experiences the Most Side Effects on Pristiq?
The likelihood of experiencing side effects can be impacted by several factors, including age, medical history, and history of side effects from other SNRIs. Certain health conditions, such as lung disease or suicidal ideation, can increase the likelihood of developing side effects. It is important to talk to your doctor about your health conditions before taking SNRIs.
Pristiq Frequently Asked Questions (FAQ) About Side Effects
Some Pristiq side effects will go away over time and some may not. It is important to see your doctor regularly to be monitored for side effects that may not go away. Pristiq may also cause weight loss by decreasing your appetite, which may or may not go away over time. Also, side effects are more likely with higher doses. Mild side effects tend to go away after the first couple of weeks.
Do Pristiq Side Effects Go Away?
Some side effects may take 1-2 weeks to subside, others may last 4-6 weeks, and some may be ongoing. Side effects, such as nausea, vomiting, constipation, dry mouth, sweating, decreased appetite, nervousness, and fatigue, will likely improve over the first few of weeks. Other side effects, like worsening depression, can last 4-6 weeks. Side effects like high blood pressure, and interstitial lung disease can be ongoing.
Does Pristiq Cause Weight Changes?
Yes, weight changes from Pristiq are possible. This side effect was not reported in clinical trials. But Pristiq can cause reduced appetite, and when treating your depression symptoms your appetite or desire to exercise may change.
Do Pristiq Side Effects Vary Based on the Dosage?
Side effects may be more likely to occur the higher the Pristiq dosage you take. Also, it has been shown that there is no added benefit for doses of 100 mg or higher, but the risk of side effects increases.4 Your doctor may start you on 25 mg or 50 mg once daily, but the recommended dose is 50 mg once daily with or without food.
Does Pristiq Cause Side Effects During the First Week?
Pristiq can cause side effects during the first 1-2 weeks. You may even notice side effects starting the first day. Side effects you would experience within the first couple of weeks include nausea, vomiting, constipation, dry mouth, sweating, decreased appetite, nervousness, and fatigue. However, many people find that these symptoms improve after a couple of weeks.
Pristiq Withdrawal
You may experience withdrawal symptoms if you discontinue Pristiq too quickly and may require immediate medical care. This is also known as antidepressant discontinuation syndrome. You may experience a headache, irritability, nausea, feeling dizzy, vomiting, nightmares, and prickling or tingling sensations.2 In rare instances, people have also experienced suicidal ideation, severe aggression, and other life-threatening symptoms.
Additional antidepressant withdrawal symptoms can include irritability, anxiety, insomnia, fatigue, and flu-like symptoms. These symptoms may indicate that you have a physical dependence, even without abuse. You may experience withdrawal symptoms within a few days of discontinuation. If you feel that you are dependent, tell your doctor and consider finding a support group.
If you want to stop taking your medication, you should talk with your prescriber first. It is important to work with your prescriber to set up a plan that is safe for you to taper off your medication to reduce the risk of discontinuation syndrome and serious side effects. Your prescriber will help you create a plan to safely lower your dose of Pristiq and stop taking your medication.
Other Warnings & Precautions For Taking Pristiq
Pristiq has many warnings that should be considered before starting the medication. It may cause an increased risk of suicidal ideation, mania, elevated blood pressure, serotonin syndrome, interstitial lung disease, eosinophilic pneumonia, discontinuation syndrome, lowered sodium levels, angle closure glaucoma, abnormal bleeding, and seizures. Some of these only apply to certain individuals.2
Precautions for taking Pristiq include:2
Increased Risk of Suicidal Thoughts
A rare but serious side effect you may experience is suicidal ideation. Young adults are more likely to experience this. If you have symptoms of worsening depression, seek immediate medical help.
Symptoms of Mania or Bipolar Disorder
Taking Pristiq may trigger bipolar disorder symptoms such as mania for people who have bipolar disorder. These symptoms may include high energy, inflated positive mood, and agitation. If you have had bipolar disorder in your health history, you should talk with your prescriber before starting Pristiq. And if you experience mania or bipolar symptoms while taking Pristiq, seek immediate medical attention.
Long-term Elevated Blood Pressure Issues
Pristiq can increase your blood pressure, whether you already have high blood pressure or not. Monitor your blood pressure when starting Pristiq to reduce the risk of blood pressure changes. If you experience high blood pressure, seek immediate medical attention. Examples of symptoms of high blood pressure include headaches, chest pain, dizziness, nausea, and vision changes.
Serotonin Syndrome
Pristiq may cause serotonin syndrome. You may feel irritable, hot, confused, have increased blood pressure or heart rate, dilated pupils, or have muscle rigidity. If you experience symptoms, seek medical help immediately.
Interstitial Lung Disease and Eosinophilic Pneumonia
Pristiq can cause long-term lung scarring that is irreversible. You may have shortness of breath, a cough, fatigue, a fever, night sweats, or chest discomfort. If you experience any of these symptoms or have difficulty breathing or shortness of breath, seek immediate medical help.
Discontinuation Syndrome
Like other SSRIs and SNRIs, Pristiq can cause discontinuation syndrome if you lower your dose too quickly. You may have symptoms such as a headache, irritability, nausea, nightmares, anxiety, insomnia, and flu-like symptoms. Seek immediate medical care if you experience any of these symptoms.
Lowered Sodium Levels
Pristiq has been known to lower sodium (salt) levels and cause side effects. The elderly and patients taking diuretics are more likely to experience low sodium levels. Symptoms include headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which can lead to falls, hallucinations, loss of consciousness, seizures, coma, respiratory arrest, and death. Seek immediate medical attention if you experience any of these symptoms.
Angle Closure Glaucoma
Pristiq may cause angle closure glaucoma. Do not take Pristiq if you have existing glaucoma or take certain medications. If you experience pupil dilation, nausea, vomiting, headache with blurry vision, severe unilateral eye pain, or rainbow-colored halos around bright lights, seek medical care immediately.
Abnormal Bleeding
SSRIs and SNRIs can increase the risk of bleeding. Do not take Pristiq if you take blood thinners or ibuprofen. If you experience bruising easily, gums bleeding when brushing your teeth, severe stomach pain, or have a serious fall, seek medical attention immediately.
Seizures
Pristiq should not be taken if you have a history of seizures. If you experience staring, jerking movements, rapid eye blinking, confusion, breathing problems, loss of bladder control, loss of consciousness, or a sudden fall, seek medical help immediately.
Questions to Ask Your Healthcare Provider About Pristiq Side Effects
You may consider using Pristiq if you have tried other medications such as SSRIs and need a different drug instead. If you’d like to know more about its side effects, ask your doctor or pharmacist for more information.
Questions to ask your care team when considering the side effects of Pristiq may include:
- Can I use Pristiq along with therapy to treat depression?
- How long will it take for me to adjust to taking Pristiq?
- 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 dosage to ensure fewer side effects?
- Are there drugs I am taking that could have negative interactions?
- When should I reach out to you if I am experiencing side effects?
- Is there anything I should tell my therapist about this new medication?
- Will Pristiq be covered by my insurance?
- Does my medical history increase my risk of side effects?
- How often should I see you for checkups while taking Pristiq?
- What should I do if I am unsure if antidepressants are right for me?
- What dose will I expect to experience more serious side effects?
- How can I prevent side effects from occurring?
- What supplements should I avoid while taking Pristiq?
- Are there drugs I am taking that could have negative interactions?
In My Experience
In my experience, patients generally tolerate Pristiq well. It is in its active form, which helps prevent side effects. It’s important to talk to your doctor about Pristiq and follow their guidance because this drug comes with many warnings. Also, you may still want to consider going to therapy, even while taking an SNRI, as having medication and therapy together is recommended.
