The effect of venlafaxine on ongoing and experimentally induced pain in neuropathic pain patients: a double blind, placebo controlled study.
OBJECTIVE
The aim of this randomized double blind placebo controlled study was to investigate the effectiveness and the safety of venlafaxine XR 75 and 150 mg on ongoing pain and on quantitative sensory tests in 60 patients with neuropathic pain for 8 weeks.


METHODS
Evaluation parameters consisted of ongoing pain intensity (VAS), patient satisfaction, side effects, global efficacy and tolerance. Quantitative sensory measurements taken from the affected area before and after the drug treatment included pin-prick hyperalgesia, allodynia, detection and pain thresholds to electrical and heat stimuli, temporal summation of repetitive electrical and heat stimuli.


RESULTS
A total of 55 patients completed the study. VAS scores decreased significantly compared to the baseline measurements in all groups. There was no significant difference between the groups regarding pain intensity and escape medication. The areas of allodynia and pin-prick hyperalgesia decreased significantly in venlafaxine groups compared to the placebo. There was no significant difference between the groups regarding the detection thresholds (electrical and heat). The pain threshold and the summation threshold to electrical stimuli and the summation threshold to heat stimuli increased significantly following treatment in both venlafaxine groups. In addition, the degree of the temporal summation to electrical and heat stimuli decreased significantly following treatment in both venlafaxine groups compared to the placebo.


CONCLUSIONS
The study showed significant effect of venlafaxine in the manifestations of hyperalgesia and temporal summation, but not on the ongoing pain intensity. Furthermore, the quantitative sensory tests provided complementing information to the clinical measures.
Department of Algology, Istanbul Faculty of Medicine, Istanbul University, Capa Klinikleri, Cerrahi Monoblok, 31080 Istanbul, Turkey. yucel@istanbul.edu.tr
A
A
Yucel
S
S
Ozyalcin
G
G
Koknel Talu
E
E
Kiziltan
B
B
Yucel
O K
OK
Andersen
L
L
Arendt-Nielsen
R
R
Disci
D000328:Adult; D000368:Aged; D000700:Analgesics / Q000008:administration & dosage* / Q000009:adverse effects; D002908:Chronic Disease; D003511:Cyclohexanols / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D004558:Electric Stimulation / Q000009:adverse effects; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D010148:Intractable Pain / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D010812:Physical Stimulation; D010919:Placebos; D013997:Time Factors; D016896:Treatment Outcome; D000069470:Venlafaxine Hydrochloride
D000700:Analgesics; D003511:Cyclohexanols; D010919:Placebos; D000069470:Venlafaxine Hydrochloride