When starting a new medication, it’s normal to feel anxious about how your body may react.
The prospect of experiencing side effects can be daunting, and depression and the medications used to treat it can affect your appetite and body weight in unwanted ways.
While side effects can range from annoying to scary, it’s also important to note that most of the time, the positive effects of the medication outweigh the negative.
In this article, we’ll review a common side effect of antidepressants: weight gain, specifically in the context of Effexor.
We’ll review what Effexor is, the relationship between this medication and weight gain, and common side effects when taking it.
We’ll also go over precautions and when to see a doctor.
What is Effexor?
Effexor (venlafaxine) is an antidepressant that is commonly prescribed to treat symptoms associated with depression and anxiety.
Effexor helps relieve symptoms that may occur with depression and anxiety, like sadness, hopelessness, guilt, and lack of interest in things that once brought you joy.
It can also be used to treat physical manifestations of anxiety, including nausea, jitters, or restlessness, amongst other things.
It can also be prescribed as a mood stabilizer, as well as used to treat post-traumatic stress disorder, bipolar disorder, and attention-deficit hyperactivity disorder.
It has also been prescribed to treat hot flashes as a result of menopause or chemothrapy.
These are “off label” uses, meaning the FDA has not approved them for these diseases but prescribers can decide if it’s appropriate for individual patients.
How Effexor works
Antidepressants work by affecting the chemicals in the brain known as neurotransmitters.
These include the managing of available levels of serotonin, norepinephrine, and dopamine.
Effexor is part of a class of drugs known as SNRIs (serotonin-norepinephrine reuptake inhibitor), which regulate the amount of serotonin and norepinephrine molecules in the brain by blocking the reabsorption or reuptake of such chemicals.
This makes more of these chemicals available in the brain and results in mood regulation.
Effexor and Weight Gain
Many antidepressant and anxiety medications list weight gain as a potential side effect.
This is the case with Effexor as well, but not everyone experiences such side effects.
What the research says
Studies show that newer antidepressant drugs may be associated with weight gain.
Some studies and clinical studies show that patients treated with Effexor gain a significant amount of weight, while other studies show that weight gain from venlafaxine is small and potentially insignificant.
While studies show that some antidepressants may cause weight gain, the effect of antidepressants on weight is still mixed and needs further examination.
Common Side Effects of Effexor
Like many medications, there are a variety of side effects that may occur when taking Effexor.
These side effects are often mild, and a doctor will usually prescribe a low dose to start and build up slowly to a higher daily dose to avoid significant side effects.
Many of the side effects should go away within a few weeks.
Common side effects include:
- Blurred vision
- Dry mouth
- Insomnia or difficulty falling asleep
- Gastrointestinal issues like heartburn, decreased appetite, constipation, gas, or diarrhea
- Vivid or unusual dreams
- Decreased sex drive or difficulty achieving orgasm or ejaculation
- Prickly or tingling sensations
Depression and Weight Changes
There are a number of signs of depression.
A common one to look out for is appetite changes.
This may include a noticeable weight gain or loss.
This may occur in both clinically depressed, as well as “high functioning” depression.
Those who are depressed may be less likely to make healthy eating choices, which may affect one’s weight more than a medication itself.
Depression also affects energy levels and your desire to do things that you once enjoyed.
This may affect one’s desire to exercise regularly, an important part of maintaining a healthy body weight.
How to Take Effexor
Effexor is often taken daily with a starting dose of 37.5 mg per day, which is increased over time to 75 mg daily, a common dosage to treat depression, generalized anxiety, panic disorders, and social anxiety disorder.
Your doctor may adjust your dosage over time, but they do not usually recommend going over 225 mg per day.
Before starting Effexor, tell your doctor about all medications and supplements you take, as some can interact with the medication and cause serious side effects.
Especially in the beginning, it is best to avoid alcohol, as venlafaxine can make you drowsy.
Before stopping Effexor, consult your doctor and they will help you wean off the medication.
Sudden and immediate stopping can cause withdrawal side effects like nausea, vomiting, headache, and irritability. It’s best to stop taking Effexor with the help of a psychiatrist.
When to See a Doctor
Speak with your doctor about what antidepressant medication is right for you.
If your side effects worsen or symptoms don’t begin to resolve in 6 weeks, you may want to try a different dose of medication.
Contact a doctor immediately if you suspect signs of an overdose, which includes dizziness, flashes of hot and cold, dilated pupils, irregular heart rate, and seizures.
With drugs that affect the serotonin levels in your brain, there is a risk of serotonin syndrome.
This is when your body has too much serotonin and requires immediate medical attention.
Symptoms include restlessness, insomnia, confusion, high blood pressure, sweating, diarrhea, headache, and goosebumps.
If you experience serious side effects, including suicidal thoughts or worsening symptoms of depression, talk to someone immediately, such as calling a suicide crisis line like 1-800-273-TALK.
Frequently Asked Questions
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Low-Dose Estradiol and the Serotonin-Norepinephrine Reuptake Inhibitor Venlafaxine for Vasomotor Symptoms. (2014.)
A drug combination that reduces weight gain associated with antidepressant therapy.
Weight gain and associated factors in patients using newer antidepressant drugs. (2014.)
Antidepressants cause minimal weight gain. (2014.)
Serotonin Syndrome. (2013.)