Common side effects of
Effexor (venlafaxine) are:

• Headarche,
• weakness,
• loss of appetite,
• weight gain or weight loss,
• stomach pains,
• sweating,
• dizziness,
• sleep problems,
• nightmares,
• tiredness,
• trembling,
• confusion,
• stiffness in the body,
• anxiety,
• nervousness,
• heartburn,
• nausea,
• constipation,
• dry mouth,
• skin blemishes,
• yawning,
• increased cholesterol level in the blood,
• sexual problems or
• loss of sex interest,
• urination problems,
• increased blood pressure,
• fainting when you rise rapidly,
• faster heart rate,
• difficulty reading small print,
• other sight problems.

If you have been using Effexor and stop using it, you can get short-term or long-term withdrawal symptoms such as:

• Dizziness,
• sensory problems,
• feeling
• like ants are crawling on your skin,
• sleeping problems,
• nightmares,
• anxiety,
• headaches,
• sweating,
• nausea,
• varying emotions,
• muscle pain.

These wihdrawal symptom can go on from one week to two months after abruptly stopping using Effexor. It is better to reduce the dose gradually instead of abruptly. If you have severe syptoms after withdrawal, you might consider increasing the dose again and then reducing the dose gradually.