pregabalin and Muscular-Diseases

Pregabalin is used for treatment of neuropathic pain conditions. The present study evaluated effects of pregabalin in 2 rat models of muscle-induced hyperalgesia: Inflammatory and noninflammatory. Muscle hyperalgesia (withdrawal threshold to compression of the muscle) and cutaneous hyperalgesia of the paw (withdrawal threshold to von Frey filaments) were measured before and after induction of hyperalgesia and after treatment with pregabalin (saline, 10 to 100 mg/kg i.p.). In the inflammatory model, 3% carrageenan injected into 1 gastrocnemius muscle decreased the mechanical withdrawal threshold of the paw bilaterally and the compression withdrawal threshold of the muscle ipsilaterally 2 weeks later. Pregabalin (10 to 100 mg/kg) increased the compression withdrawal threshold of the inflamed muscle when compared with vehicle controls. Pregabalin also increased the mechanical withdrawal threshold of the paw bilaterally, but only with 100 mg/kg. In the noninflammatory model, 2 unilateral injections of acidic saline into the gastrocnemius muscle produced bilateral cutaneous and muscle hyperalgesia 24 hours after the second injection. Pregabalin (10 to 100 mg/kg i.p.) significantly increased the compression withdrawal thresholds of the muscle and the mechanical withdrawal threshold of the paw bilaterally when compared with vehicle. However, pregabalin also has significant motor effects at the higher doses (60 to 100 mg/kg). Therefore, pregabalin reduces both muscle and cutaneous hyperalgesia that occurs after muscle insult in 2 animal models of muscle pain at doses that do not produce ataxia.. This study shows that pregabalin reduces both cutaneous and muscle hyperalgesia in inflammatory and noninflammatory models of muscle pain. Thus, pregabalin may be an effective treatment for people with chronic muscle pain.

Topics: Analgesics; Animals; Carrageenan; Chronic Disease; Disease Models, Animal; Dose-Response Relationship, Drug; Functional Laterality; gamma-Aminobutyric Acid; Hyperalgesia; Male; Motor Activity; Muscle, Skeletal; Muscular Diseases; Pain; Pain Threshold; Pregabalin; Rats; Rats, Sprague-Dawley; Reaction Time; Skin; Time Factors

Chronic muscle pain is a problem with high prevalence in clinical practice and its pharmacological treatment is difficult. There is a lack of animal models which reliably predict analgesic activity of drugs on muscle pain. Here we used intramuscular injection of tumor necrosis factor-alpha (TNF) in rats as a model of muscle pain. In this model we tested the antihyperalgesic action of lacosamide in comparison to the analgesics pregabalin and gabapentin. Mechanical withdrawal thresholds to muscle pressure were measured with an algesimeter exerting pressure on the gastrocnemius muscles previously injected with TNF. Fore limb grip strength was measured with a digital grip force meter after TNF injection into the biceps brachii muscles. A complete reversal of hyperalgesia was seen with lacosamide at 30mg/kg. Significant effects were also seen for pregabalin at 30 and 100mg/kg and gabapentin at 100mg/kg. In biceps muscle hyperalgesia, a significant reversal of hyperalgesia was seen with lacosamide at 10mg/kg. Significant effects were also seen for pregabalin and gabapentin at 100mg/kg. We could thus demonstrate in a rat model for myalgia that lacosamide effectively reduces muscular hyperalgesia and is somewhat more potent than gabapentin and pregabalin.

Topics: Acetamides; Amines; Animals; Behavior, Animal; Cyclohexanecarboxylic Acids; Excitatory Amino Acid Antagonists; Gabapentin; gamma-Aminobutyric Acid; Hand Strength; Hyperalgesia; Lacosamide; Male; Muscular Diseases; Pain; Pregabalin; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factors