Use of intrathecal SNX-111, a novel, N-type, voltage-sensitive, calcium channel blocker, in the management of intractable brachial plexus avulsion pain.
OBJECTIVE
The objective was to assess the analgesic, antihyperesthesic, and anti-allodynic properties of SNX-111 in neuropathic pain.


METHODS
We describe a patient with refractory, severe deafferentation pain successfully treated with SNX-111 in an open-label, baseline-controlled Phase I/II trial.


METHODS
The patient was hospitalized for treatment and observation.


METHODS
The patient was a 43-year-old man with intractable deafferentation pain of 23 years' duration secondary to brachial plexus avulsion.


METHODS
SNX-111, the first neuron-specific, N-type, voltage-sensitive calcium channel blocker developed for clinical use, was administered by continuous, constant-rate, intrathecal infusion via an indwelling cervical catheter.


METHODS
The primary outcome measures were the Visual Analog Scales of Pain Intensity (VASPI) and Pain Relief (VASPR).


RESULTS
The patient experienced complete pain relief (VASPI = 0.0 cm and VASPR = 10.0 cm) with elimination of hyperesthesia and allodynia.


CONCLUSIONS
SNX-111, administered intrathecally by continuous, constant-rate infusion, produced dose-dependent pain relief in a 43-year-old male patient with a 23-year history of intractable deafferentation and phantom limb pain secondary to brachial plexus avulsion and subsequent amputation. Dizziness, blurred vision, and lateral-gaze nystagmus were dose-dependent side effects that resolved with decreasing dose levels. Complete pain relief was achieved in this patient without side effects after dose adjustment. We conclude that SNX-111 is a potent analgesic, antihyperesthesic, and antiallodynic agent. Controlled studies of SNX-111 in patients with malignant and nonmalignant pain syndromes are warranted and are under way.
Brose
W G
WG
Department of Anesthesia, Stanford University Medical Center, Palo Alto, California, USA.
Gutlove
D P
DP
Luther
R R
RR
Bowersox
S S
SS
McGuire
D
D
D000328:Adult; D001917:Brachial Plexus / Q000293:injuries*; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D010147:Pain Measurement; D010148:Intractable Pain / Q000188:drug therapy* / Q000209:etiology / Q000523:psychology; D010455:Peptides / Q000008:administration & dosage / Q000627:therapeutic use*; D010591:Phantom Limb / Q000188:drug therapy; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D010455:Peptides; D020960:omega-Conotoxins; C078452:ziconotide