Efficacy of Venlafaxine for Depression

According to recent studies comparing antidepressant treatments, more patients achieved remission, or virtual elimination, of their depression symptoms and resolution of both emotional and physical symptoms when they took venlafaxine (Canadian Effexor®, Wyeth) than other selective serotonin reuptake inhibitors (SSRIs) or placebo. The findings were revealed at the European College of Neuropsycho-pharmacology’s annual meeting in Prague, Czech Republic.

The data were pooled after completion of more than 30 comparable, randomized, double-blind, active, drug-controlled clinical studies conducted worldwide in more than 7,000 patients with major depressive disorder. Nine of these studies were also placebo-controlled. Investigators in all of the double-blinded studies randomly assigned patients to receive venlafaxine, extended-release venlafaxine (XR), or another SSRI.

Patients who took venlafaxine had significantly higher remission rates than those taking the other SSRIs, as measured by to the Hamilton Rating Scale for Depression (HAM-D17) or the Mont-gomery-Asberg Depression Rating Scale (MADRS).

Venlafaxine was also more effective than the SSRIs in reducing the anxiety and somatization symptoms associated with depression, according to the HAM-D21 scale. More patients taking ven-lafaxine achieved resolution of their general somatic symptoms of depression.

Backache, headache, muscle aches, loss of energy, fatigue, and heaviness in the limbs, back, and head can also occur in addition to the emotional symptoms inherent in depression. In these studies, 38% of the patients in the generic venlafaxine group achieved resolution of their general somatic symptoms, compared with 32% of the SSRI patients and 25% of placebo patients.

Venlafaxine is believed to increase levels of serotonin and norepinephrine, two of the brain chemicals thought to be implicated in depression, Generalized Anxiety Disorder (GAD), and Social Anxiety Disorder (SAD).

The most commonly reported adverse drug events were anorexia, asthenia, constipation, dizziness, dry mouth, ejaculation problems, impotence, insomnia, nausea, nervousness, somnolence, and sweating. Patients should be counseled about possible symptoms if they discontinue the medication abruptly or reduce the dose.

Venlafaxine is contraindicated in patients taking monoamine oxidase inhibitors, and in children and teenagers because of the potential risk of suicidal thoughts. Treatment is associated with sustained increases in blood pressure in some patients, and regular monitoring is recommended.

The FDA approved the immediate-release formulation in 1993 and the extended-release formulation in 1997.