The effect of venlafaxine HCl on painful peripheral diabetic neuropathy in patients with type 2 diabetes mellitus.

OBJECTIVE

The objective of this study was to evaluate the efficacy of venlafaxine HCl in the symptomatic treatment of painful peripheral diabetic neuropathy (PPDN) among patients with type 2 diabetes mellitus (DM).

DESIGN

This study was designed as a prospective, randomized, and controlled trial.

SETTING

This study was conducted at the Dicle University Medical Faculty (Diyarbakir, Turkey).

PATIENTS

Sixty type 2 DM outpatients (47 females and 13 males) with PPDN who had a minimum visual analog scale (VAS) score of 40 mm were enrolled in this study.

INTERVENTIONS

Patients randomized to the treatment group (n=30) received venlafaxine HCl, whereas those randomized to the control group (n=30) received a combination of vitamins B(1)and B(6) tablets.

MEASURES

Severity of pain was measured by VAS, Short-Form McGill Pain Questionnaire, and numerical analog scale scores at admission and at the second, fourth, and eighth weeks of the study. Polyneuropathy was supported by electromyelography.

OUTCOME

In the treatment group, severity of pain was measured as 70.0+/-13.0 in the VAS, as 24.9+/-6.2 in the Short-Form McGill Pain Questionnaire, and as 7.2+/-1.1 in the numerical analog scale. In the control group, it was measured as 73.0+/-8.0 in the VAS, as 26.8+/-6.2 in the Short-Form McGill Pain Questionnaire, and as 7.4+/-0.8 in the numerical analog scale (P>.05).

RESULTS

The most common form of PPDN was distal symmetrical sensorimotor polyneuropathy in both groups (46.8% vs. 50.0%). At the end of the study, there was a significant difference in severity of pain between the groups. In the treatment group, scores were 8.5+/-5.2 and 3.1+/-1.6 in the Short-Form McGill Pain Questionnaire and numerical analog scale, respectively; in the control group, these were 20.5+/-7.0 and 5.5+/-1.6, respectively (P<.001).

CONCLUSIONS

Venlafaxine HCl is a safe and well-tolerable analgesic drug in the symptomatic treatment of PPDN; however, it has minimal adverse effects. It showed its efficacy markedly in the second week of therapy.