Introduction: The objective of this study is to investigate analgesic effectiveness and safety of venlafaxine extended release in chronic pain of any etiology.
Methods: Six month, observational, open study, carried out in two pain units. Initially, a daily dose of 75 mg of venlafaxine extended release was administered, increasing it to 150 mg, following clinical criteria. Treatment response was measured using the Visual Analogue Scale (VAS), rest and mobilization, Hospital Anxiety and Depression Scale (HAD) and Eastern Cooperative Oncology Group (ECOG) and an adverse event sheet to record adverse events occurring during the study.
Results: The study was carried out in a 50 patient sample with a mean age of 57.1 +/- 1.8 years, with chronic pain. A total of 85-90 % of the patients was maintained with a daily dose of 75 mg of venlafaxine extended release. This produced a gradual reduction of the VAS scores at rest (significant reduction of 5.2 +/- 1.1 to 2.7 +/- 1.5 points; (p<0.0005) and mobilization (significant reduction of 5.5 +/- 0.8 to 3.1 +- 1.6 points; p<0.0005). Pain relief increased progressively. Regarding physical activity measured by the ECOG scale, there was a reduction of the percentage of patients and increase of outpatients. Tolerability to venlafaxine was "excellent", "very good" or "good" for 72% of the patients.
Conclusions: Extended release venlafaxine can be an effective and well-tolerated treatment in patients with chronic pain of any etiology, although it must be investigated in depth.