Resources - Medications
Effexor (venlafaxine)
What is Effexor?
Effexor XR (venlafaxine HCL) is a medication available to treat depression and generalized anxiety disorder (GAD). Structurally different from any other antidepressant, it affects two neurotransmitters (chemical messengers in the brain) involved in depression, serotonin and norepinephrine. Approved for use in the United States at the end of 1993, its novel chemical action and low incidence of side effects make it a significant addition to the range of medications used to treat depression and GAD.
How is Effexor XR different from other antidepressants?
Effexor XR is a chemically unique antidepressant medication. Like the newer class of antidepressants known as selective serotonin reuptake inhibitors (SSRIs), such as Prozac (fluoxetine) and Zoloft (sertraline), it affects the absorption of serotonin. In addition, Effexor XR acts on the norepinephrine system. No other available medication affects both neurotransmitters without causing the side effects of the older tricyclic antidepressants.
Are there other advantages of Effexor XR?
Effexor XR is less likely to induce seizures, to have toxic effects on the heart, and to cause lethal reactions than the older tricyclic antidepressants.
For what kind of patient would Effexor XR be appropriate?
Effexor XR is recognized as an effective front-line option (that is, first-time medication) for patients who have recently become ill with depression or who have GAD, whether they are hospitalized or treated on an outpatient basis. It can also be useful for patients who have had longstanding depressive illness and have not responded adequately to previous treatments. Almost 40 percent of so-called refractory patients (those who have not had positive results from past treatment) have had success with Effexor XR. Patients who have benefited from other antidepressants but have had less than complete success may want to discuss switching to Effexor XR with their doctors.
What about side effects?
Relatively few side effects have been reported with Effexor XR. Those that have been noted are dose-related; that is, side effects increase as the dose increases. Very few patients have had to discontinue the medication because of side effects.
The most common minor side effects during clinical trials include short-term nausea (which can be reduced by taking the medication with food), sleepiness, dry mouth, dizziness, constipation, nervousness, sweating, weakness, ejaculation/orgasm problems, and loss of appetite.
A small percentage (about five percent) of patients, usually those taking higher doses, will develop elevated blood pressure. Therefore, patients taking Effexor XR should have their blood pressure checked regularly. Some agitation has been noticed at higher dosages. Patients who stop Effexor XR abruptly may experience dizziness, nausea, vertigo, and shock-like symptoms. Therefor, slow tapering is recommended.
How long does it take to work?
Like most other medications used for depression, Effexor XR may take several weeks before it is fully effective. It is important to give the medication sufficient time before judging whether it will work for a given person. There is evidence, however, that Effexor XR may take effect more quickly than other antidepressants.
Can Effexor XR be taken with other medications?
Effexor XR does not interact significantly with many other medications, including lithium, Valium (diazepam), and Tagamet (cimetidine, an anti-ulcer medication). However, patients taking Tagamet who have high blood pressure or liver disease or are elderly should use caution in taking Effexor XR because the interaction may be more pronounced when these disorders are present.
Effexor XR definitely should not be taken at the same time as the MAOIs (such as Parnate or Nardil). Interactions with these compounds could be lethal. Patients who have been taking an MAOI and are switching to Effexor XR must allow sufficient time (usually 14 days) for the MAOI to clear out of the body. The same time should be allowed if changing from Effexor XR to an MAOI. However, switching from Effexor XR to other medications is easy because Effexor XR is quickly removed from the body.
What is the standard dose?
The dose range is generally between 75 and 225 mg per day, although lower and higher doses may be safe and effective. Higher doses are necessary for those with more severe symptoms. Effexor XR should be take once daily. Dosage adjustments for elderly people are not usually necessary. Will Effexor XR work for everyone?
No. Everyone responds to medications differently. Effexor XR will work well for some people, and not so well for others. It is important to give the medication a trial of several weeks and to be in close communication with your doctor about signs of effectiveness, side effects, and personal factors affecting one's response to the medication.
Reviewed by Jack Gorman, M.D., Chair NAMI Scientific Council, Sept 2002
Information from NAMI's Website (http://www.nami.org)
