Jan 23, 2009


Venlafaxine is racemates R-and S-enantiomers, both have pharmacological activity. The main metabolite - O-desmetilvenlafaksin that are in the blood plasma than venlafaksine - has similar antidepressive activity, which may soon be presented as a separate product.

Venlafaxine inhibits serotonin transporter protein, but in high doses - as norepinephrine transporter. This drug has no affinity to muscarinic, adrenergic, histamine, 5-HT1-and 5-HT2-serotonin receptors.

T1 / 2 venlafaxine is 5 h, O-desmetilvenlafaksin - 11 h. Binding venlafaxine with plasma protein is 27%, significantly lower than that of SSRI (for example, fluoxetine - 94%, paroxetine - 95%). Since venlafaxine inhibit CYP2D6, it may impede the normal metabolism of other drugs, metabolic this proferment.

Most studies have shown similar efficacy venlafaxine and other antidepressants. In comparison with sertralin and estsitalopram, venlafaxine demonstrated similar effectiveness of these drugs in treating patients with severe depression and in improving their quality of life. A meta-analysis showed an advantage over venlafaksin SSRI, but the analysis had been included only studies with the use of fluoxetine and paroxetine, and the results can not be extrapolated to all SSRI. Large meta-analysis combined the results of 33 RKI involving patients with deep depression that took venlafaxine, fluoxetine, paroxetine and fluvoxamin. The level of remission when receiving venlafaxine was 45%, while taking SSRI - 35%, and placebo control group - 25%. Similar results (more efficiency venlafaxine compared with SSRI) has been demonstrated in other large meta-analysis.

Meta-analysis was criticized because it venlafaksin compared with SSRI in low doses, which could not affect the results. This has led the authors of a new, more accurate studies, but the result was the same. The depth of the effect and the frequency of remission was higher in the application venlafaxine. It was concluded that venlafaxine is really more effective antidepressant compared with SSRI. In parallel, there were reports that there is no significant difference in performance between the second generation of antidepressants, and only minor (but statistically reliable) venlafaxine advantages and sertralin compared with fluoxetine. The decisive criterion in such situations has become controversial speed the onset of clinically significant effect, and venlafaxine in this regard has obvious advantages. In particular, the effect when receiving high-dose venlafaxine occur 1-2 weeks after admission (compared with placebo). The scheme with the rapid build-up of a daily dose venlafaxine to 375 mg / day to achieve strong clinical effect is already over 1 week of therapy.

The same is not enough data on the duration of remission in treatment venlafaxine compared with SSRI. A long reception venlafaxine (12 months), only 22% of patients moved relapse of depression, while in the placebo group the rate was 55% (p <0001), which favors the use of drugs for maintenance therapy to prevent relapse of depression.

Interestingly, in a meta-analysis, together 3 273 patients in the group venfalaxine of SSRI group and 932 patients in the placebo group, demonstrated the effectiveness of preferential venlafaxine in the reduction of somatic symptoms on a scale of HAM-D compared with SSRI and placebo. Profile portability venlafaxine reflects its pharmacodynamics: on the one hand, there are serotoninenergic (nausea, vomiting, sexual dysfunction, etc.), on the other - noradrenergic (sweating, dry mouth, increased heart rate and blood pressure). It is noted that the increase of blood pressure are about 3% of patients, and this effect is likely to be dose dependent.

Venlafaxine does not cause sedation and antiholinergic appearance. The number of interrupt treatment is the same as other antidepressants in the treatment of the second generation. One of the most dangerous complication is a severe hyponatremia (occurs very rarely), which leads to the syndrome of inadequate giperprodukt antidiuretic hormone, especially if the initially low levels of sodium (for example, in the accompanying admission diuretics).

Good medicine with proven effectiveness.

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