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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is still a need for a new analgesic devoid of the side effects presented by opioids or non-steroidal anti-inflammatory drugs, for the treatment of some acute and chronic pain conditions. Lamotrigine (Lamictal1, 10-100 mg/kg), a new anticonvulsant, showed analgesic effects in the acute model of prostaglandin E2 (PGE2)-induced hyperalgesia when given orally before or after the subplantar injection of PGE2 in the rat. It also inhibited the development of sustained hyperalgesia induced by multiple subplantar injections of PGE2 when administered orally prior to the PGE2 injections. Furthermore, lamotrigine induced analgesia in the model of chronic hyperalgesia in streptozotocin-induced diabetic rats. The effects of carbamazepine and phenytoin are compared to the effects of lamotrigine in this model. The results suggest that lamotrigine could be used in pain conditions where neuronal sensitization may be present and possibly also where it could inhibit the development of this sensitization.
Pain 1995 Oct
PMID:Effect of lamotrigine in the acute and chronic hyperalgesia induced by PGE2 and in the chronic hyperalgesia in rats with streptozotocin-induced diabetes. 857 88

Pain associated with hyperalgesia of the affected area occurs in a number of conditions. We describe our experience of using the drug Lamotrigine in the management of this pain in 3 individuals with Phantom limb pain and stump hypersensitivity Post herpetic neuralgia and causalgia respectively. We discuss the mechanism of action of the drug and why possibly it renders it effective in this form of pain.
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PMID:Lamotrigine for pain with hyperalgesia. 910 25

The novel anti-epileptic drugs lamotrigine, felbamate and gabapentin were compared in rat experimental models of acute (tail flick) and chronic pain: the chronic constriction injury and spinal nerve ligation models. Lamotrigine (10-100 mg/kg, s.c.), felbamate (150-600 mg/kg, i.p.) and gabapentin (30-300 mg/kg, i.p.) each reversed cold allodynia (chronic constriction injury model) with ED50 values of 28, 241 and 103 mg/kg, respectively, 1 h post-dose. However, only gabapentin reversed tactile allodynia (spinal nerve ligation model) with an ED50 of 34 mg/kg (i.p.). The established anti-epileptic drugs, carbamazepine (1-30 mg/kg, i.p.) and phenytoin (1-100 mg/kg, s.c.), were ineffective in both models. The anti-allodynic effect of the newer anti-epileptic drugs was observed at doses that were either ineffective or produced only a negligible effect on acute nociceptive function and/or locomotor activity. In conclusion, the data suggest that the newer anti-epileptic drugs appear to have the potential to be effective alternatives to either carbamazepine or phenytoin in the treatment of neuropathic pain. However, only gabapentin ameliorated both cold and touch hyperesthesias.
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PMID:The effect of novel anti-epileptic drugs in rat experimental models of acute and chronic pain. 914 66

Lamotrigine is a chemically novel antiepileptic drug which has not been adequately assessed for its antineuralgic properties. It was used in a double-blind placebo controlled crossover trial in 14 patients with refractory trigeminal neuralgia. Patients continued to take a steady dose of carbamazepine or phenytoin throughout the trial over a 31-day period. Each arm of the trial lasted 2 weeks with an intervening 3-day washout period. The maintenance dose of lamotrigine was 400 mg. Lamotrigine was superior to placebo (P = 0.011) based on analysis of a composite efficacy index which compared the numbers of patients assigned greater efficacy on lamotrigine with those assigned greater efficacy on placebo. Efficacy for one treatment over another was determined according to a hierarchy of: (i) use of escape medication; (ii) total pain scores; or (iii) global evaluations. Eleven of the 13 patients eligible for inclusion in the composite efficacy index showed better efficacy on lamotrigine compared with placebo. Global evaluations further suggested that patients did better on lamotrigine than placebo (P = 0.025). The adverse reactions with both lamotrigine and placebo were predominantly dose-dependent effects on the central nervous system. A 14th patient withdrew from the study due to severe pain during the placebo arm of the trial. It would appear that lamotrigine has antineuralgic properties.
Pain 1997 Nov
PMID:Lamotrigine (lamictal) in refractory trigeminal neuralgia: results from a double-blind placebo controlled crossover trial. 969 85

Lamotrigine, a sodium channel blocker that selectively inhibits the neuronal release of glutamate, has been shown to produce analgesia in acute and chronic pain models in rats without causing noticeable sedation. After oral administration it also reduces pain scores, as assessed by the cold pain test, in volunteers. The purpose of this study was to determine the analgesic effect of lamotrigine given by mouth to healthy volunteers as evidenced by alterations in chemo-somatosensory evoked potentials. The following factors were measured: latency to N1 and P100 peak (ms); amplitude between the N1 and P100 peak (microV); visual analogue pain intensity scores. A double-blind, randomised and crossover design was used in which 12 volunteers received either placebo or lamotrigine 300 mg on separate occasions as determined by the randomisation schedule. Volunteers were tested before and 2 h after the treatment. The plasma lamotrigine concentration was measured immediately after the end of the experimental sessions. Lamotrigine produced a significantly higher latency to P100 values at 2 h postdrug than placebo (p < 0.05) but had no significant effects on the other factors. Although plasma concentrations were similar to those observed in the cold pain test, we conclude that lamotrigine 300 mg by mouth had no analgesic effect in this acute pain model.
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PMID:Effects of lamotrigine on pain-induced chemo-somatosensory evoked potentials. 1046 May 30

Neuropathic pain, a form of chronic pain caused by injury to or disease of the peripheral or central nervous system, is a formidable therapeutic challenge to clinicians because it does not respond well to traditional pain therapies. Our knowledge about the pathogenesis of neuropathic pain has grown significantly over last 2 decades. Basic research with animal and human models of neuropathic pain has shown that a number of pathophysiological and biochemical changes take place in the nervous system as a result of an insult. This property of the nervous system to adapt morphologically and functionally to external stimuli is known as neuroplasticity and plays a crucial role in the onset and maintenance of pain symptoms. Many similarities between the pathophysiological phenomena observed in some epilepsy models and in neuropathic pain models justify the rational for use of anticonvulsant drugs in the symptomatic management of neuropathic pain disorders. Carbamazepine, the first anticonvulsant studied in clinical trials, probably alleviates pain by decreasing conductance in Na+ channels and inhibiting ectopic discharges. Results from clinical trials have been positive in the treatment of trigeminal neuralgia, painful diabetic neuropathy and postherpetic neuralgia. The availability of newer anticonvulsants tested in higher quality clinical trials has marked a new era in the treatment of neuropathic pain. Gabapentin has the most clearly demonstrated analgesic effect for the treatment of neuropathic pain, specifically for treatment of painful diabetic neuropathy and postherpetic neuralgia. Based on the positive results of these studies and its favourable adverse effect profile, gabapentin should be considered the first choice of therapy for neuropathic pain. Evidence for the efficacy of phenytoin as an antinociceptive agent is, at best, weak to modest. Lamotrigine has good potential to modulate and control neuropathic pain, as shown in 2 controlled clinical trials, although another randomised trial showed no effect. There is potential for phenobarbital, clonazepam, valproic acid, topiramate, pregabalin and tiagabine to have antihyperalgesic and antinociceptive activities based on result in animal models of neuropathic pain, but the efficacy of these drugs in the treatment of human neuropathic pain has not yet been fully determined in clinical trials. The role of anticonvulsant drugs in the treatment of neuropathic pain is evolving and has been clearly demonstrated with gabapentin and carbamazepine. Further advances in our understanding of the mechanisms underlying neuropathic pain syndromes and well-designed clinical trials should further the opportunities to establish the role of anticonvulsants in the treatment of neuropathic pain.
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PMID:Anticonvulsants for neuropathic pain syndromes: mechanisms of action and place in therapy. 1112 21

The prophylactic management of recurrent head and facial pains may be challenging because of lack of efficacy and/or bothersome adverse effects of available drug therapies. New generation antiepileptic drugs offer new perspectives in difficult cases. We will review the available published data and present our experience with lamotrigine in various head and facial pains such as migraine, cluster headache, neuropathic trigeminal pain, atypical facial pain, and chronic tension-type headache. Twenty-five patients were enrolled and followed for 18 months. The dose was gradually increased in steps of 25 mg up to the effective dose (mean 250 mg/d). Lamotrigine was most effective in trigeminal neuralgia and dysesthesia, but was of little utility in the other head or facial pains.
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PMID:New generation anti-epileptics for facial pain and headache. 1137 75

Neuropathic pain, whether of peripheral or central origin, is characterized by a neuronal hyperexcitability in damaged areas of the nervous system. In peripheral neuropathic pain, damaged nerve endings exhibit abnormal spontaneous and increased evoked activity, partly due to an increased and novel expression of sodium channels. In central pain, although not explored in detail, the spontaneous pain and evoked allodynia are also best explained by a neuronal hyperexcitability. The peripheral hyperexcitability is due to a series of molecular changes at the level of the peripheral nociceptor, in dorsal root ganglia, in the dorsal horn of the spinal cord, and in the brain. These changes include abnormal expression of sodium channels, increased activity at glutamate receptor sites, changes in gamma-aminobutyric acid (GABA-ergic) inhibition, and an alteration of calcium influx into cells. The neuronal hyperexcitability and corresponding molecular changes in neuropathic pain have many features in common with the cellular changes in certain forms of epilepsy. This has led to the use of anticonvulsant drugs for the treatment of neuropathic pain. Carbamazepine and phenytoin were the first anticonvulsants to be used in controlled clinical trials. Studies have shown these agents to relieve painful diabetic neuropathy and paroxysmal attacks in trigeminal neuralgia. Subsequent studies have shown the anticonvulsant gabapentin to be effective in painful diabetic neuropathy, mixed neuropathies, and postherpetic neuralgia. Lamotrigine, a new anticonvulsant, is effective in trigeminal neuralgia, painful peripheral neuropathy, and post-stroke pain. Other anticonvulsants, both new and old, are currently undergoing controlled clinical testing. The most common adverse effects of anticonvulsants are sedation and cerebellar symptoms (nystagmus, tremor and incoordination). Less common side-effects include haematological changes and cardiac arrhythmia with phenytoin and carbamazepine. The introduction of a mechanism-based classification of neuropathic pain, together with new anticonvulsants with a more specific pharmacological action, may lead to more rational treatment for the individual patient with neuropathic pain.
Eur J Pain 2002
PMID:Anticonvulsants in neuropathic pain: rationale and clinical evidence. 1188 43

The objective was to investigate the effectiveness of lamotrigine for the treatment of spinal cord injury pain and clinical signs of neuronal hyperexcitability. Thirty patients with spinal cord injury (SCI) and at or below level neuropathic pain participated in a randomized double blind, placebo-controlled, crossover trial. A 1-week baseline period was followed by two treatment periods of 9 weeks duration with lamotrigine slowly increased to a maximum of 400 mg or placebo separated by a 2-week washout period. The primary outcome measure was the change in median pain score from baseline week to the last week of treatment. Secondary outcome measures included thresholds to standardized sensory stimuli using quantitative sensory testing. Twenty-two patients completed the trial. We found no statistically significant effect of lamotrigine as evaluated in the total sample. However, in patients with incomplete SCI, lamotrigine significantly reduced pain at or below SCI level. Patients with brush evoked allodynia and wind-up-like pain in the area of maximal pain were more likely to have a positive effect to lamotrigine than patients without these evoked pains (7 of 7 vs. 1 of 14). Lamotrigine was generally well tolerated. While this trial showed no significant effect on spontaneous and evoked pain in complete and incomplete spinal cord injury, lamotrigine reduced spontaneous pain in patients with incomplete spinal cord injury and evoked pain in the area of spontaneous pain.
Pain 2002 Apr
PMID:Lamotrigine in spinal cord injury pain: a randomized controlled trial. 1197 12

Emerging evidence from animal models of neuropathic pain suggests that many pathophysiologic and biochemical changes occur in the peripheral and central nervous system. Similarities between the pathophysiologic phenomena observed in some epilepsy models and in neuropathic pain models justify the use of anticonvulsants in the symptomatic management of neuropathic pain. Positive results from laboratory and clinical trials further support such use. Carbamazepine was the first of this class of drugs to be studied in clinical trials and has been longest in use for treatment of neuropathic pain. Clinical trial data support its use in treating trigeminal neuralgia, but data for treatment of painful diabetic neuropathy are less convincing. Use of newer anticonvulsants has marked a new era in the treatment of neuropathic pain. Gabapentin has demonstrated efficacy, specifically in painful diabetic neuropathy and postherpetic neuralgia. Lamotrigine has been reported to be effective in relieving pain from trigeminal neuralgia refractory to other treatments, HIV neuropathy, and central post-stroke pain. Results from clinical trials of phenytoin are equivocal. Zonisamide's mechanisms of action suggest that it would be effective in controlling neuropathic pain symptoms. Other anticonvulsants, including lorazepam, valproate, topiramate, and tiagabine, have also been under investigation. Anecdotal experience provides support for studies with oxcarbazepine and levetiracetam for treating neuropathic pain. Evidence supporting the efficacy of anticonvulsants in treatment of such pain is evolving. Additional clinical trials should provide information that will better define their role in neuropathic pain.
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PMID:Use of anticonvulsants for treatment of neuropathic pain. 1222 Nov 51


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