A placebo-controlled trial of lamotrigine for painful HIV-associated neuropathy.
OBJECTIVE
To investigate the analgesic efficacy of lamotrigine in the treatment of painful HIV-associated distal sensory polyneuropathy (DSP).


BACKGROUND
The pathogenesis of HIV-associated DSP is unknown and there is no effective treatment. A novel anticonvulsant, lamotrigine, blocks voltage-sensitive sodium channels and inhibits the release of glutamate and aspartate. There have been anecdotal reports of efficacy of lamotrigine in the treatment of painful neuropathy and trigeminal neuralgia.


METHODS
In a multicenter, randomized, double-blind, placebo-controlled study, lamotrigine was initiated at 25 mg per day and slowly titrated over 7 weeks to 300 mg per day. Study duration was 14 weeks. The primary outcome measure was change in pain on the modified Gracely scale with secondary outcome measures including change in neurologic examination, use of concomitant analgesic medications, and global pain relief.


RESULTS
Of 42 enrolled subjects, 13 did not complete the 14-week study endpoint. In five of these, rash was the cause for dropout. In the remaining 29 evaluable subjects, 20 patients received placebo and 9 received lamotrigine. The pain scores at baseline were not significantly different. The reduction in average pain from baseline to week 14 was greater (p = 0.03) in the lamotrigine group (-0.55) than in the placebo group (-0.18), adjusting for baseline levels of pain. There was no difference between the groups on the change in peak worst pain.


CONCLUSIONS
In this small trial, lamotrigine showed promise in the treatment of pain associated with HIV-related DSP. The frequency of rash was greater than in lamotrigine studies in epilepsy. A larger controlled study of lamotrigine is warranted.
Simpson
D M
DM
Mount Sinai Medical Center, New York, NY 10029, USA. david.simpson@mssm.edu
Olney
R
R
McArthur
J C
JC
Khan
A
A
Godbold
J
J
Ebel-Frommer
K
K
D000328:Adult; D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use*; D000704:Analysis of Variance; D004311:Double-Blind Method; D003875:Drug Eruptions / Q000209:etiology; D005076:Exanthema / Q000139:chemically induced; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D000077213:Lamotrigine; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy*; D011115:Polyneuropathies / Q000188:drug therapy* / Q000209:etiology; D014227:Triazines / Q000009:adverse effects / Q000627:therapeutic use*
D000700:Analgesics; D014227:Triazines; D000077213:Lamotrigine