What are the side effects of Effexor (Venlafaxine)?

From the Guidelines

Effexor (venlafaxine) is associated with a range of side effects, including nausea, headache, dizziness, and sexual dysfunction, as reported in a clinical practice guideline from the American College of Physicians 1. When considering the side effects of Effexor, it is essential to weigh the potential benefits against the risks, particularly in terms of morbidity, mortality, and quality of life.

Common Side Effects

Some of the most commonly reported side effects of Effexor include:

• Nausea and vomiting, which are also the most common reasons for discontinuation in efficacy studies 1
• Diarrhea, dizziness, headache, insomnia, and somnolence
• Sexual adverse events, which can be a significant concern for patients

Severe Adverse Events

More severe side effects can include:

• Sexual dysfunction, with paroxetine having higher rates of sexual dysfunction than fluoxetine, fluvoxamine, nefazodone, or sertraline 1
• Suicidality, with some meta-analyses suggesting an increased risk of nonfatal suicide attempts associated with SSRIs, although the evidence is not conclusive 1
• Other severe adverse events, such as seizures, cardiovascular events, and weight changes

Management of Side Effects

To minimize the risk of side effects, it is crucial to:

• Start with a low dose (37.5-75mg daily) and gradually increase as needed and under medical supervision
• Monitor blood pressure regularly, as Effexor can cause increased blood pressure
• Be aware of the potential for serotonin syndrome, particularly when combining Effexor with other serotonergic medications
• Never stop taking Effexor suddenly, as this can lead to severe withdrawal symptoms; instead, follow a gradual tapering schedule under medical supervision 1

From the FDA Drug Label

Venlafaxine HCl and other antidepressant medicines may cause serious side effects, including:

1. Suicidal thoughts or actions
2. Serotonin Syndrome
3. Changes in blood pressure
4. Enlarged pupils (mydriasis)
5. Anxiety and insomnia
6. Changes in appetite or weight
7. Manic/hypomanic episodes
8. Low salt (sodium) levels in the blood
9. Abnormal bleeding
10. Elevated cholesterol
11. Lung disease and pneumonia
12. Severe allergic reactions

Common possible side effects in people who take venlafaxine HCl include: • unusual dreams • sexual problems • loss of appetite, constipation, diarrhea, nausea or vomiting, or dry mouth • feeling tired, fatigued or overly sleepy • change in sleep habits, problems sleeping • yawning • tremor or shaking • dizziness, blurred vision • sweating • feeling anxious, nervous or jittery • headache • increase in heart rate

The side effects of Effexor (venlafaxine) include serious side effects such as suicidal thoughts or actions, serotonin syndrome, and changes in blood pressure, as well as common side effects like unusual dreams, sexual problems, and loss of appetite. It is essential to monitor patients for these side effects and report any concerns to a healthcare provider. 2 2 2

From the Research

Side Effects of Effexor

• The most common adverse effects of venlafaxine are nausea, somnolence, and dry mouth 3
• The overall tolerability of venlafaxine appears to exceed that of tricyclic antidepressants and compares favorably with that of selective serotonin reuptake inhibitors 3
• Dropouts due to adverse effects increased steeply through the examined range of doses of venlafaxine 4
• The relationship between the dose and dropouts for any reason indicated optimal acceptability for venlafaxine in the lower licensed range between 75-150 mg 4
• Venlafaxine was not associated with an excess risk of sudden cardiac death or near death compared with fluoxetine, dosulepin, or citalopram, in patients with depression or anxiety 5
• Compared to all SSRIs, venlafaxine was associated with a greater response and remission, but overall drop out rates appeared similar 6
• Tricyclics were less well tolerated with higher overall drop out rates compared to venlafaxine 6