Preclinic and clinic effectiveness of gabapentin and pregabalin for treatment of neuropathic pain in rats and diabetic patients

Pregabalin and gabapentin are amino-acid derivatives of gamma-aminobutyric acid. They have a high affinity to the α2δ protein in the central nervous system and both have been shown to be effective for neuropathic pain disorder. The aim of this study was to investigate the efficacy of gabapentin and pregabalin in animal models of neuropathic pain, and to correlate with clinical outcomes in patients with diabetic neuropathy. Gabapentin (60 mg/kg) and pregabalin (30 mg/kg) attenuate mechanical, tactile and heat hypersensitivity in rats with chronic constriction injury of the sciatic nerve and streptozotocin (STZ)-induced diabetes. There is no evidence that one of the drugs is superior to another at the different rat models and tests. In the incisional pain model, there was partial efficacy of gabapentin. Our clinical data suggest that relative to the baseline pain score, the treatment with pregabalin at doses of 300 mg/day or gabapentin at doses of 900 mg/day would be effective and well tolerated in patients diagnosed with moderate diabetic polyneuropathy. The study suggested that pregabalin may provide better analgesic outcomes than gabapentin on the sixth month of treatment. In conclusion, the comparative effects of gabapentinoids in animal models of neuropathic pain and neuropathic patients are suggestive of similar pathophysiological mechanisms being involved, but successful outcome is determined by a patient's individuality and the drug nature as well as the drug tolerability.