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, with nausea and vomiting being the most common reasons for discontinuation, 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 benefits of treatment against the potential risks. The most commonly reported adverse events include:

• Constipation
• Diarrhea
• Dizziness
• Headache
• Insomnia
• Nausea
• Sexual adverse events
• Somnolence These side effects are similar to those of other second-generation antidepressants, with some differences in incidence. For example, venlafaxine has a higher incidence of nausea and vomiting than other SSRIs, while sertraline has a higher rate of diarrhea than some other medications 1. Severe adverse events associated with Effexor include:
• Sexual dysfunction, with bupropion having a significantly lower rate of sexual adverse events than fluoxetine or sertraline 1
• Suicidality, with some meta-analyses suggesting an increased risk of nonfatal suicide attempts with SSRIs, although the evidence is not conclusive 1
• Other severe adverse events, such as seizures and cardiovascular events, although the evidence evaluating these risks is limited 1. It is crucial to monitor patients taking Effexor for increased blood pressure, especially at higher doses, and to taper the medication slowly under medical supervision to avoid withdrawal symptoms. Patients should be advised to consult their healthcare provider if side effects are severe or persistent, rather than stopping the medication suddenly.

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 for these side effects and report any concerns to a healthcare provider 2.

Some of the other side effects reported in the studies include:

• Cardiovascular problems: migraine, angina pectoris, arrhythmia, and thrombophlebitis 2
• Digestive issues: eructation, bruxism, colitis, and gastrointestinal ulcer 2
• Nervous system problems: trismus, vertigo, akathisia, and hallucinations 2
• Respiratory issues: bronchitis, dyspnea, asthma, and pneumonia 2

From the Research

Side Effects of Effexor (Venlafaxine)

• The most common side effects of Effexor include nausea, headache, and dizziness 3
• Other possible side effects include dry mouth, constipation, and increased sweating 3
• Effexor can also cause sexual dysfunction, such as decreased libido and erectile dysfunction 4
• In rare cases, Effexor can cause more serious side effects, such as serotonin syndrome, which can be life-threatening 5

Comparison to Other Antidepressants

• Effexor has been shown to be more effective than some selective serotonin reuptake inhibitors (SSRIs) in treating major depression 3
• Effexor has also been shown to be at least as effective as tricyclic antidepressants in treating major depression 3
• However, Effexor can have a higher risk of side effects, such as nausea and dizziness, compared to some other antidepressants 4

Drug Interactions

• Effexor can interact with other medications, such as SSRIs and opioids, to increase the risk of serotonin syndrome 5
• Patients taking Effexor should be closely monitored for symptoms of serotonin syndrome, such as agitation, confusion, and rapid heart rate 5
• Effexor should not be taken with certain medications, such as monoamine oxidase inhibitors (MAOIs), due to the risk of serotonin syndrome 5