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, and it is essential to weigh these risks against the potential benefits of treatment. When considering the use of Effexor, it is crucial to be aware of the potential side effects, as identified in a clinical practice guideline from the American College of Physicians 1. The most commonly reported adverse events included:

• Constipation
• Diarrhea
• Dizziness
• Headache
• Insomnia
• Nausea
• Sexual adverse events
• Somnolence Nausea and vomiting were the most common reasons for discontinuation in efficacy studies, and Venlafaxine had a higher incidence of nausea and vomiting than other SSRIs 1. Severe adverse events associated with Effexor include sexual dysfunction and suicidality, although the risk for suicidality is not significantly different among second-generation antidepressants 1. It is essential to monitor patients taking Effexor for these potential side effects and to discuss any concerns with their healthcare provider. Patients should not stop taking Effexor suddenly, as this can lead to severe withdrawal symptoms, and dosage should be gradually reduced under medical supervision.

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
• Changes in blood pressure
• Enlarged pupils (mydriasis)
• Anxiety and insomnia
• Changes in appetite or weight
• Manic/hypomanic episodes
• Low salt (sodium) levels in the blood
• Abnormal bleeding
• Elevated cholesterol
• Lung disease and pneumonia
• Severe allergic reactions And common possible side effects such as:
• 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 2, 2, 2

From the Research

Side Effects of Effexor (Venlafaxine)

The side effects of Effexor (Venlafaxine) can be categorized into several groups, including:

• Common side effects:
  • Nausea 3, 4, 5
  • Diarrhea 3
  • Fatigue or somnolence 3, 6
  • Sexual side effects 3, 4, 5
  • Dry mouth 5
  • Dizziness 5
  • Constipation 5
  • Insomnia 5
  • Asthenia 5
  • Tremor 5
  • Decreased appetite 5
• Cardiovascular side effects:
  • Mild increases in blood pressure 3
  • Diaphoresis 3
  • Tachycardia 3
  • QT interval prolongation, which can lead to torsades de pointes 4
• Psychotic symptoms:
  • Delusions of persecution 7
• Other side effects:
  • Weight gain 6
  • Concentration difficulties 6
  • Sleepiness/sedation 6
  • Failing memory 6
  • Increased risk of suicidal thoughts or behaviors 5

Serious Adverse Events

Venlafaxine has been associated with an increased risk of serious adverse events, including:

• Sexual dysfunction 5
• Anorexia 5
• Suicidal thoughts or behaviors 5

Long-term Effects

The long-term effects of venlafaxine are unknown, which is a particular cause for concern given that many people use these drugs for several years 5.