It is important that your doctor check your progress at regular visits, to allow for changes in your dose and to help reduce any side effects.

Tell your doctor right away if you develop any allergic reactions, such as skin rash or hives, while taking venlafaxine.

Venlafaxine may cause some people to be agitated, irritable or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these adverse effects, tell your doctor right away.

Do not stop taking EFFEXOR without first checking with your doctor. Your doctor may want you to reduce gradually the amount you are taking before stopping completely. This is to decrease the chance of side effects.

It is not known how venlafaxine will interact with alcohol and other central nervous system (CNS) depressants (medicines that may make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using EFFEXOR.

Venlafaxine may cause some people to become drowsy or have blurred vision. Make sure you know how you react to EFFEXOR before you drive, use machines, or do anything else that could be dangerous if you are not alert or able to see clearly.

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Changes in vision, such as blurred vision;  decrease in sexual desire or ability;  headache 
  
  

• Less common
  • Chest pain;  fast or irregular heartbeat ;  mood or mental changes;  ringing or buzzing in ears 
  
  

• Rare
  • Convulsions (seizures);  itching or skin rash;  lightheadedness or fainting, especially when getting up suddenly from a sitting or lying position;  lockjaw;  menstrual changes;  problems in urinating or in holding urine;  swelling ;  talking, feeling, and acting with excitement and activity you cannot control;  trouble in breathing  
  
  

• Symptoms of overdose
  • Agitation;  convulsions (seizures);  drowsiness;  extreme tiredness or weakness ;  fast heartbeat;  tingling, burning, or prickling sensations;  trembling or shaking  
  
  

EFFEXOR may also cause the following side effect that your doctor will watch for:

• More common
  • High blood pressure 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Abnormal dreams;  anxiety or nervousness ;  chills;  constipation;  diarrhea;  dizziness;  drowsiness;  dryness of mouth;  heartburn;  increased sweating;  loss of appetite;  nausea;  stuffy or runny nose;  stomach pain or gas;  tingling, burning, or prickly sensations;  trembling or shaking;  trouble in sleeping;  unusual tiredness or weakness;  vomiting ;  weight loss 
  
  

• Less common
  • Change in sense of taste;  muscle tension ;  yawning 
  
  

After you stop using EFFEXOR, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this period of time check with your doctor if you notice any of the following side effects:

• Actions that are out of control;  anxiety ;  changes in dreaming;  continuing ringing or buzzing or other unexplained noise in ears;  convulsions;  crying;  depersonalization;  diarrhea;  difficulty with coordination;  dizziness;  dryness of mouth;  dysphoria;  euphoria;  fear;  feeling of constant movement of self or surroundings;  feeling unwell or unhappy;  headache;  hearing loss;  hyperventilation;  increased sweating;  irregular heartbeats ;  irritability;  lightheadedness ;  loss of appetite;  loss of bladder control;  mental depression;  mood or mental changes;  muscle spasm or jerking of all extremities;  nausea;  nervousness;  nightmares;  paranoia;  quick to react or overreact emotionally;  rapidly changing moods;  restlessness;  sensation of spinning ;  sensory disturbances (including shock-like electrical sensations;  shakiness in legs, arms, hands, feet ;  shaking;  shaking of hands or feet;  shortness of breath;  sleeping or unusual drowsiness;  sudden loss of consciousness ;  talking, feeling, and acting with excitement;  trembling or shaking of hands or feet;  trouble in sleeping;  twitches of the muscle visible under the skin;  unusual drowsiness, dullness or feeling of sluggishness;  unusual tiredness or weakness;  vomiting;  weight loss 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, venlafaxine is used in certain patients with the following medical condition:

• Hot flashes

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.