33297
document
Effects of gabapentin on experimental somatic pain and temporal summation . BACKGROUND AND OBJECTIVES Gabapentin is used for treatment of neuropathic pain , but its effect on different somatic pain modalities and integrative mechanisms are not completely understood . The aim of this double-blind , placebo-controlled experimental pain study , conducted on 20 healthy volunteers , was to examine the effect of a single dose of 1200 mg gabapentin on multi-modal experimental cutaneous and muscle pain models . METHODS The following pain models were applied : ( 1 ) pain thresholds to single and repeated cutaneous and intramuscular electrical stimulation ( temporal summation to 5 stimuli delivered at 2 Hz ) ; ( 2 ) stimulus-response function relating pain intensity scores ( visual analog scale , VAS ) to increasing current intensities for electrical skin and muscle stimuli ( single and repeated , determined at baseline ) ; and ( 3 ) the pain intensity ( VAS ) and pain areas after intramuscular injection of hypertonic saline . Pain assessments were performed prior to , and at 4 , 6 , and 8 hours after medication . RESULTS When responses were averaged across the post-dose times , gabapentin : ( 1 ) significantly increased the temporal summation pain threshold in skin compared with placebo ( P = .03 ) ; ( 2 ) significantly reduced the area under the pain intensity curve to hypertonic saline injections in the muscle ( P = .02 ) ; and ( 3 ) significantly reduced the area of pain evoked by hypertonic saline ( P = .03 ) . CONCLUSIONS Gabapentin reduces temporal summation of skin stimuli at pain threshold intensities ; this may have potential as a biomarker for drugs with efficacy on neurogenic pain . The data also suggest that tonic muscle pain is responsive to gabapentin treatment and suggest further clinical studies .
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Intervention_Pharmacological
gabapentin
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Intervention_Pharmacological
Gabapentin
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Intervention_Control
placebo-controlled
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Intervention_Physical
single and repeated cutaneous and intramuscular electrical stimulation ( temporal summation to 5 stimuli delivered at 2 Hz )
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Intervention_Physical
pain intensity ( VAS )
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Intervention_Physical
pain areas
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Intervention_Pharmacological
intramuscular injection of hypertonic saline .
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Intervention_Pharmacological
gabapentin
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Intervention_Pharmacological
Gabapentin
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Outcome_Pain
somatic pain
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Outcome_Physical
temporal summation
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Outcome_Pain
pain intensity scores ( visual analog scale , VAS )
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Outcome_Pain
pain intensity ( VAS ) and pain areas after intramuscular injection
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Outcome_Pain
Pain
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Outcome_Pain
temporal summation pain threshold
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Outcome_Pain
area under the pain intensity curve to hypertonic saline injections
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Outcome_Pain
area of pain evoked by hypertonic saline
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Outcome_Pain
temporal summation of skin stimuli at pain threshold intensities
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Outcome_Pain
tonic muscle pain
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Participant_Sample-size
20
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Participant_Condition
healthy