Lyrica (pregabalin) is a modulator of voltage-gated calcium channels, designed to affect neurological transmission in multiple systems.
Lyrica is specifically indicated for the treatment of neuropathic pain associated with spinal cord injury. It is also indicated for the treatment of neuropathic pain associated with diabetic peripheral neuropathy, for postherpetic neuralgia, for fibromyalgia, and as an adjunctive therapy for adults with partial onset seizures.
Lyrica is supplied as a hard-gelatin capsule for oral administration. The recommended initial dose of the drug for the treatment of neuropathic pain associated with spinal cord injury is 150 mg/day (75 mg twice/day), which can be escalated to 300 mg/day within the first week. The maximum dosing regimen is 600 mg/day.
The FDA approval of Lyrica for neuropathic pain associated with spinal cord injury was based on the results of two randomized, double-blind, flexibly dosed (150-600 mg/day), placebo-controlled trials. Subjects were enrolled with baseline pain scores of at least four on a scale of zero (no pain) to eleven (worst pain), and were permitted to continue taking other pain medications, including NSAIDs, opioids and non-opioids. The total enrollment was 357 subjects. The first study was 12 weeks in duration and consisted of a 3week dose adjustment phase and a 9-week dose maintenance phase in subjects with neuropathic pain from traumatic spinal cord injuries. The second study was 16 weeks in duration and consisted of a 4-week dose adjustment phase and a 12-week dose maintenance phase in subjects with neuropathic pain from non-traumatic spinal cord injuries. In both trials, Lyrica treatment statistically significantly improved the endpoint weekly mean pain score, and increased the number of subjects with at least a 30% and 50% reduction in pain score from baseline compared to placebo. Some subjects observed a decrease in pain within the first week of treatment with a sustained improvement throughout the studies.
Adverse reactions associated with the use of Lyrica may include, but are not limited to, the following:
Lyrica (pregabalin) binds with high affinity to the alpha2-delta site (an auxiliary subunit of voltage-gated calcium channels) in central nervous system tissues. While the complete mechanism of action is not entirely understood, studies in animal models of nerve damage have shown Lyrica to reduce calcium-dependent release of pro-nociceptive neurotransmitters in the spinal cord, possibly by disrupting alpha2-delta containing-calcium channel trafficking and/or reducing calcium currents. Other animal models of nerve damage and persistent pain suggest the anti-nociceptive activities of pregabalin may also be mediated through interactions with descending noradrenergic and serotonergic pathways originating from the brainstem that modulate pain transmission in the spinal cord.
Siddall PJ, Cousins MJ, Otte A, Griesing T, Chambers R, Murphy TK. Pregabalin in central neuropathic pain associated with spinal cord injury: a placebo-controlled trial. Neurology 2006 Nov 28;67(10):1792-800.
For additional information regarding Lyrica or neuropathic pain associated with spinal cord injury, please visit the Lyrica web page.