Comparison of the effectiveness of amitriptyline and gabapentin on chronic neuropathic pain in persons with spinal cord injury.
OBJECTIVE
To test the hypotheses that both amitriptyline and gabapentin are more effective in relieving neuropathic pain than an active placebo, diphenhydramine.


METHODS
Randomized, controlled, double blind, triple crossover 8-week trial.


METHODS
Veterans Affairs medical center.


METHODS
Community dwelling adults with spinal cord injury (N=38) were recruited by telephone, letters, and flyers.


METHODS
Eight-week trial each of amitriptyline, gabapentin, and diphenhydramine.


METHODS
Pain intensity measured with a 10-cm visual analog scale (VAS) and an 11-point (0-10) numeric rating scale (NRS) and depressive symptomatology measured with the Center for Epidemiologic Studies Depression Scale-Short Form (CESD-SF).


RESULTS
Baseline VAS scores for participants with low (< 10) CESD-SF scores was 4.61 and for those with high scores (> or = 10) it was 7.41. At week 8, in participants with high baseline CESD-SF scores, amitriptyline (mean, 4.21) was more effective than diphenhydramine (mean, 6.67; P=.035), and there was a nonsignificant trend suggesting that amitriptyline may be more effective than gabapentin (mean, 6.68; P=.061). Gabapentin was no more effective than diphenhydramine (P=.97). There was no significant difference among the medications for those with lower CESD-SF scores. Results could not be attributed to dropout rates, order or dose of medications, amount of medication taken for breakthrough pain, or side effects.


CONCLUSIONS
Amitriptyline is more efficacious in relieving neuropathic pain than diphenhydramine at or below the level of spinal cord injury in people who have considerable depressive symptomatology.
Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX 77030, USA. drintala@bcm.tmc.edu
Diana H
DH
Rintala
Sally Ann
SA
Holmes
Daisy
D
Courtade
Richard Neil
RN
Fiess
Luz Viviana
LV
Tastard
Paul G
PG
Loubser
D000328:Adult; D000368:Aged; D000588:Amines / Q000009:adverse effects / Q000627:therapeutic use*; D000639:Amitriptyline / Q000009:adverse effects / Q000627:therapeutic use*; D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use*; D000704:Analysis of Variance; D000929:Antidepressive Agents, Tricyclic / Q000009:adverse effects / Q000627:therapeutic use*; D018592:Cross-Over Studies; D003509:Cyclohexanecarboxylic Acids / Q000009:adverse effects / Q000627:therapeutic use*; D004155:Diphenhydramine / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D000077206:Gabapentin; D006634:Histamine H1 Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020422:Mononeuropathies / Q000209:etiology; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement; D013119:Spinal Cord Injuries / Q000150:complications*; D005680:gamma-Aminobutyric Acid / Q000009:adverse effects / Q000627:therapeutic use*
D000588:Amines; D000700:Analgesics; D000929:Antidepressive Agents, Tricyclic; D003509:Cyclohexanecarboxylic Acids; D006634:Histamine H1 Antagonists; D000639:Amitriptyline; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D004155:Diphenhydramine