venlafaxine, Effexor

GENERIC NAME: venlafaxine

BRAND NAME: Effexor, Effexor XR

DRUG CLASS AND MECHANISM: Venlafaxine is in a new class of anti-depressant medications that affects chemical messengers within the brain. These chemical messengers are called neurotransmitters, and some examples are serotonin, dopamine, and norepinephrine. Neurotransmitters are manufactured by nerve cells and are released by the cells. The neurotransmitters travel to nearby nerve cells and cause the cells to become more or less active. Many experts believe that an imbalance in these neurotransmitters is the cause of depression and also may play a role in anxiety. Venlafaxine is believed to work by inhibiting the release or affecting the action of these neurotransmitters. Venlafaxine is available in an extended release formulation (Effexor XR).



PREPARATIONS: Effexor is available in tablets of 25, 37.5, 50, 75, and 100 mg. Effexor XR is available in capsules of 37.5, 75, and 150 mg.

STORAGE: Store in a dry place at 20-25°C (68-77°F).

PRESCRIBED FOR: Venlafaxine is prescribed for the treatment of depression, depression with associated symptoms of anxiety, generalized anxiety disorder, and social anxiety disorder. Effexor XR is approved for the treatment of adults with panic disorder.

DOSING: Venlafaxine should be taken with food at doses specifically directed by a physician. Individual doses vary greatly among individuals. The anti-depressant effects are not maximal for 1-2 weeks. If discontinued, the dose of venlafaxine should gradually be reduced under the direction of a physician. For patients with difficulty swallowing tablets or capsules, capsules of Effexor XR can be opened and the contents sprinkled on a spoonful of applesauce.

DRUG INTERACTIONS: Life-threatening interactions can occur in combination with MAO inhibitors such as Nardil and Parnate. MAO inhibitors and venlafaxine should not be taken together, and a waiting period of 14 days between taking these two classes of medications is strongly advised.

Most medications affecting the brain such as venlafaxine have the potential to slow reflexes or impair judgment. Therefore, caution is advised especially early in the course of treatment.

Safety has not been established in children below the age of 18 years.

PREGNANCY: The effects of venlafaxine on the fetus are unknown.

NURSING MOTHERS: It is not known if venlafaxine is secreted in milk and, therefore, if it may have an effect on nursing infants.

SIDE EFFECTS: Venlafaxine, like most anti-depressants, can cause nausea, headaches, anxiety, insomnia, drowsiness, and loss of appetite. Increased blood pressure can occur, and blood pressure should be monitored. Seizures have been reported.

"If anti-depressants are discontinued abruptly, symptoms may occur such as dizziness, headache, nausea, changes in mood, or changes in the sense of smell, taste, etc. (Such symptoms even may occur when even a few doses of anti-depressant are missed.) Therefore, it is recommended that the dose of anti-depressant be reduced gradually when therapy is discontinued."

Reference: FDA Prescribing Information

Last Editorial Review: 1/10/2006

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