Venlafaxine (Systemic)

Brand name(s): Effexor

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For venlafaxine, the following should be considered:

Allergies-Tell your doctor if you have ever had any unusual or allergic reaction to venlafaxine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy-Studies have not been done in pregnant women. However, when pregnant rats were given venlafaxine in doses much larger than the usual human dose, some of their pups died before or soon after birth. Before taking this medicine, make sure your doctor knows if you are pregnant (especially if it is the third trimester) or if you may become pregnant.

Breast-feeding-This medicine passes into breast milk and may cause unwanted effects. It may be necessary for you to take another medicine or to stop breast-feeding during treatment. Be sure you have discussed the risks and benefits of this medicine with your doctor.

Children-Venlafaxine must be used with caution in children with depression. Studies have shown occurrences of children thinking about suicide or attempting suicide in clinical trials for this medicine. More study is needed to be sure venlafaxine is safe and effective in children.

Older adults-In studies done to date that have included elderly people, venlafaxine did not cause different side effects or problems in older people than it did in younger adults.

Other medicines-Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking venlafaxine, it is especially important that your health care professional know if you are taking the following:

• Buspirone (e.g., BuSpar) or
• Bromocriptine (e.g., Parlodel) or
• Certain tricyclic antidepressants (amitriptyline [e.g., Elavil], clomipramine [e.g., Anafranil], or imipramine [e.g., Tofranil]) or
• Dextromethorphan (cough medicine) or
• Levodopa (e.g., Sinemet) or
• Lithium (e.g., Eskalith) or
• Meperidine (e.g., Demerol) or
• Nefazodone (e.g., Serzone) or
• Pentazocine (e.g., Talwin) or
• Selective serotonin reuptake inhibitors (fluoxetine [e.g., Prozac], fluvoxamine [e.g., Luvox], paroxetine [e.g., Paxil], sertraline [e.g., Zoloft]) or
• Street drugs (LSD, MDMA [e.g., ecstasy], marijuana) or
• Sumatriptan (e.g., Imitrex) or
• Tramadol (e.g., Ultram) or
• Trazodone (e.g., Desyrel) or
• Tryptophan-Using these medicines with venlafaxine may increase the chance of developing a rare, but very serious, unwanted effect known as the serotonin syndrome; symptoms of this syndrome include confusion, diarrhea, fever, poor coordination, restlessness, shivering, sweating, talking or acting with excitement you cannot control, trembling or shaking, or twitching; if you experience these symptoms contact your doctor as soon as possible

• Moclobemide (e.g., Manerex)-Taking moclobemide and venlafaxine together or less than 3 days apart may increase the chance of developing serious unwanted effects, including the serotonin syndrome, and is not recommended

• Monoamine oxidase (MAO) inhibitor activity (isocarboxazid [e.g., Marplan], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], selegiline [e.g., Eldepryl], tranylcypromine [e.g., Parnate])- Do not take venlafaxine while you are taking or within 2 weeks of taking an MAO inhibitor; if you do, you may develop confusion, agitation, restlessness, stomach or intestinal symptoms, sudden high body temperature, extremely high blood pressure, and severe convulsions; at least 14 days should be allowed between stopping treatment with an MAO inhibitor and starting treatment with venlafaxine, and at least 7 days should be allowed between stopping treatment with venlafaxine and starting treatment with an MAO inhibitor

Other medical problems-The presence of other medical problems may affect the use of venlafaxine. Make sure you tell your doctor if you have any other medical problems, especially:

• Bipolar disorder (mood disorder with alternating episodes of mania and depression) or risk of-May make condition worse. Your doctor will check you for this condition.

• Brain disease or damage, or mental retardation or
• Seizures (history of)-The risk of seizures may be increased

• Heart disease or
• High or low blood pressure-Venlafaxine may make these conditions worse

• Kidney disease or
• Liver disease-Higher blood levels of venlafaxine may occur, increasing the chance of side effects; your doctor may need to adjust your venlafaxine dose

• Mania (history of)-The risk of developing mania may be increased

• Weight loss-Venlafaxine may cause weight loss; this weight loss is usually small, but if a large weight loss occurs, it may be harmful in some patients

Last Revised: 01/10/2005