Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new gabapentin research articles will be listed here shortly after becoming available to us.
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Medical research on gabapentin
[Gabapentin for neurophatic pain in children: a case report.]
Agri. 2008 Apr; 20(2): 37-40
Dayıoğlu M, Tuncer S, Reisli R
Gabapentin is used as an analgesic in neuropathic pain. In this report a children with nerophatic pain because of mercury poising was followed-up for pain and side effects with the use of gabapentin. Pain reduction was good throughout the patient treatment. Severe side effects did not occur. Gabapentin was effective and well tolerated in the treatment of neuropathic pain in children.
Chem Biol Drug Des. 2008 Nov 5;
Vasudev PG, Aravinda S, Ananda K, Veena SD, Nagarajan K, Shamala N, Balaram P
Gabapentin, a widely used antiepileptic drug, crystallizes in multiple polymorphic forms. A new crystal form of gabapentin monohydrate in the space group Pbca is reported and the packing arrangement compared with that of a previously reported polymorph in the space group P2(1)/c [Ibers, J.A. (2001) Acta Crystallogr; C57:641]. Gabapentin polymorphs can also occur from a selection of one of the two distinct chair forms of the 1,1-disubstituted cyclohexane. Crystal structures of the E and Z isomers of 4-tert-butylgabapentin provide models for analyzing anticipated packing modes in the conformational isomers of gabapentin. The E isomer crystallized in the space group Pca2(1), while the Z isomer crystallized in the space group P2(1)/c. The crystal structure of E-4-tert-butylgabapentin provides the only example of a structure in a non-centrosymmetric space group. Crystal structures of the hydrochloride and hydrobromide salts of 4-tert-butyl derivatives are reported. The results suggest that for gabapentin, a large 'polymorph-space' may be anticipated, in view of the multiple conformational states that are accessible to the molecule.
J Chin Med Assoc. 2008 Nov; 71(11): 583-6
Liu FC, Fuh JL, Wang SJ
A patient with symptomatic trigeminal autonomic cephalalgia (TAC) provides a chance to understand the pathophysiology and anatomic correlates of TAC. A 28-year-old woman experienced intermittent sharp and excruciating pain over her right temporal, ear and neck regions for 3 days. The headaches lasted 10-20 minutes each, occurred 1-2 times a day, and were accompanied by prominent ipsilateral lacrimation and conjunctival injection. The patient had hiccups, 4-limb numbness and impaired visual acuity in both eyes. She had also had 3 episodes of left-side optic neuritis in the past half year. Neurologic examination showed brushing allodynia over the right face and scalp during the headache attacks. The visual acuity of her right eye was 6/60 and that of the left eye was 1/60. Brain magnetic resonance imaging showed non-enhancing lesions on the right lateral tegmentum of the lower pons where the spinal trigeminal nucleus is located and the floor of the 4th ventricle. The patient was diagnosed as having multiple sclerosis with symptomatic TAC. Her headaches, autonomic signs and allodynia subsided 3 days after pulse therapy and gabapentin treatment were given. We suggest that the spinal trigeminal nucleus lesion was responsible for the symptomatology of TAC and cutaneous allodynia in our patient.
A cost-utility comparison of four first-line medications in painful diabetic neuropathy.
Pharmacoeconomics. 2008; 26(12): 1045-64
O'Connor AB, Noyes K, Holloway RG
BACKGROUND: Painful diabetic neuropathy is common and adversely affects patients' quality of life and function. Several treatment options exist, but their relative efficacy and value are unknown. OBJECTIVE: To determine the relative efficacy, costs and cost effectiveness of the first-line treatment options for painful diabetic neuropathy. METHODS: Published and unpublished clinical trial and cross-sectional data were incorporated into a decision analytic model to estimate the net health and cost consequences of treatment for painful diabetic peripheral neuropathy over 3-month (base case), 1-month and 6-month timeframes. Efficacy was measured in QALYs, and costs were measured in $US, year 2006 values, using a US third-party payer perspective.The patients included in the model were outpatients with moderate to severe pain associated with diabetic peripheral neuropathy and no contraindications to treatment with tricyclic antidepressants. Four medications were compared: desipramine 100 mg/day, gabapentin 2400 mg/day, pregabalin 300 mg/day and duloxetine 60 mg/day. RESULTS: Desipramine and duloxetine were both more effective and less expensive than gabapentin and pregabalin in the base-case analysis and through a wide range of sensitivity analyses. Duloxetine offered borderline value compared with desipramine in the base case ($US47 700 per QALY), but not when incorporating baseline-observation-carried-forward analyses of the clinical trial data ($US867 000 per QALY). The results were also sensitive to the probability of obtaining pain relief with duloxetine. CONCLUSIONS: Desipramine (100 mg/day) and duloxetine (60 mg/day) appear to be more cost effective than gabapentin or pregabalin for treating painful diabetic neuropathy. The estimated value of duloxetine relative to desipramine depends on the assumptions made in the statistical analyses of clinical trial data.
Efficient assessment of neuropathic pain drugs in patients with small fiber sensory neuropathies.
Pain. 2008 Nov 13;
Ho TW, Backonja M, Ma J, Leibensperger H, Froman S, Polydefkis M
We sought to develop an enrichment crossover study design that would allow us to efficiently evaluate and compare promising candidate neuropathic pain drugs. We evaluated the efficacy of gabapentin or tramadol vs. active placebo (diphenhydramine) in subjects with biopsy-proven painful idiopathic small fiber neuropathy (SFN) who were self-reported gabapentin responders. Eligible subjects entered two single blind run-in phases. In the first phase (Period A), subjects were treated with single blinded gabapentin at their prestudy dose followed by a second run-in phase (Period B) in which they were treated with diphenhydramine active placebo. Subjects with 3 pain and a 30% increase in pain intensity in Period B compared to Period A were then randomized to a double-blind three period cross over trial of gabapentin at pre study dosage, tramadol 50mg QID and diphenhydramine 50mgqhs. Of the 59 subjects enrolled, 41 subjects were excluded: Twenty-three had an insufficient rise in pain intensity in Period B; eight had skin biopsies that did not confirm SFN. Eighteen subjects were randomized into the double-blind, crossover phase. There was a significant treatment effect of gabapentin vs. diphenhydramine (p=0.001) and tramadol vs. diphenhydramine (p=0.018) by the before-bed daily pain score averaged over the final 7 days of each treatment period. We conclude that gabapentin and tramadol were effective in the treatment of painful SFN and that this experimental enrichment paradigm is attractive to screen potential neuropathic pain compounds for efficacy in proof-of-concept studies.
Oxadiazolone bioisosteres of pregabalin and gabapentin.
Bioorg Med Chem Lett. 2008 Oct 25;
Wustrow DJ, Belliotti TR, Capiris T, Kneen CO, Bryans JS, Field MJ, Williams D, El-Kattan A, Buchholz L, Kinsora JJ, Lotarski SM, Vartanian MG, Taylor CP, Donevan SD, Thorpe AJ, Schwarz JB
A series of oxadiazolone bioisosteres of pregabalin 1 and gabapentin 2 were prepared, and several were found to exhibit similar potency for the alpha(2)-delta subunit of voltage-gated calcium channels. Oxadiazolone 9 derived from 2 achieved low brain uptake but was nevertheless active in models of osteoarthritis. The high clearance associated with compound 9 was postulated to be a consequence of efflux by OAT and/or OCT, and was attenuated on co-administration with cimetidine or probenecid.
Epilepsy Behav. 2008 Nov 13;
Arif H, Buchsbaum R, Weintraub D, Pierro J, Jr SR, Hirsch LJ
Subjective cognitive side effects (CSEs) are common in patients taking antiepileptic drugs (AEDs). The objectives of this study were to predict those patients at risk for CSEs and to compare the CSE profiles of all commonly used AEDs. In this nonrandomized retrospective study, medical records of 1694 adult outpatients with epilepsy seen at our center over a 5-year period who had taken one or more AEDs were examined. Non-AED predictors of CSEs were investigated, and rates of AED-related CSEs were compared in 1189 patients (546 on monotherapy) newly started on an AED at our center. The average rate of AED-related, intolerable CSEs (leading to dosage change or discontinuation) was 12.8%. On multivariate analysis, no significant non-AED predictors of CSEs were found. Significantly more intolerable CSEs were attributed to topiramate (21.5% of 130 patients) than to most other AEDs, including carbamazepine (9.9%), gabapentin (7.3%), levetiracetam (10.4%), lamotrigine (8.9%), oxcarbazepine (11.6%), and valproate (8.3%). CSE rates with zonisamide (14.9%) were significantly higher than those for gabapentin and lamotrigine. After exclusion of CSEs during the first 8 weeks of therapy, rates of CSEs were lower, but relative differences remained unchanged. In monotherapy, significantly more intolerable CSEs occurred with topiramate (11.1% of 18 patients) than with carbamazebine or valproate, and both phenytoin and zonisamide were associated with more CSEs than valproate. Intolerable patient-reported CSEs are most common with topiramate, followed by zonisamide, phenytoin, and oxcarbazepine. They are least likely to be reported with gabapentin, valproate, lamotrigine, carbamazepine, and levetiracetam.
Naunyn Schmiedebergs Arch Pharmacol. 2008 Nov 11;
Brawek B, Löffler M, Weyerbrock A, Feuerstein TJ
One site of action of the anticonvulsant, analgesic, and anxiolytic drugs gabapentin and pregabalin is the alpha(2)delta-subunit of voltage-sensitive Ca(2+) channels (VSCC). We therefore analyzed the effects of gabapentin and pregabalin on K(+)-evoked release of (3)H-gamma-aminobutyric acid (GABA) and (3)H-glutamate from superfused human neocortical synaptosomes. These neurotransmitters are released by Ca(2+)-dependent exocytosis and by Ca(2+)-independent uptake reversal. When a GABA transport inhibitor was present throughout superfusion to isolate exocytotic conditions, gabapentin and pregabalin (100 muM each) reduced K(+)-evoked (3)H-GABA release by 39% and 47%, respectively. These effects were antagonized by the alpha(2)delta-ligand L: -isoleucine (1 muM) suggesting the alpha(2)delta-subunit of terminal VSCC to mediate the reduction of exocytosis. Both drugs had no effect on exocytotic (3)H-glutamate release and also failed to modulate the release of (3)H-GABA and (3)H-glutamate caused by reversed uptake in the absence of external Ca(2+). Thus, an inhibition of glutamate release by gabapentin and pregabalin as main anticonvulsant principle is not supported by our experiments. An anticonvulsant mode of action of both drugs may be the reduction of a proconvulsant exocytotic GABA release.
Rash Associated with Pregabalin Use (December).
Ann Pharmacother. 2008 Nov 11;
Smith TL, Baldwin A, Cunningham Jr LL, Cook AM
OBJECTIVE: To report a case of extensive rash induced by orally administered pregabalin in a patient with neuropathic pain. CASE SUMMARY: A 35-year-old white female with a diffuse, erythematous, maculopapular rash localized to her back and extremities presented to the preoperative holding area for planned exploratory nerve surgery. Prior to presentation, she had been receiving oral pregabalin 50 mg 3 times a day for approximately 2 weeks to treat her neuropathy. Prior to pregabalin therapy, the patient indicated that she had taken gabapentin for approximately 3 weeks for the pain, but had discontinued it due to adverse effects and perceived lack of efficacy. Pregabalin was discontinued and diphenhydramine and methylprednisolone were given to treat the rash. The rash almost completely resolved one week after pregabalin was discontinued. DISCUSSION: Pregabalin-induced rash was rarely reported in Phase 3 trials, and a clinical description of such events has not been published. Pregabalin exhibits pharmacokinetics different from those of most other antiepileptic agents. Presently, there are no clear mechanisms known for rash associated with pregabalin. The Naranjo probability scale indicates a probable relationship between the development of rash and use of pregabalin by our patient. CONCLUSIONS: There are currently no other available reports of the development of a rash coinciding with the use of pregabalin. As both Food and Drug Administration-approved and off-label use of this drug increases, further consideration of risk factors associated with the development of rash is needed.
Pharmacotherapy of essential tremor : an overview of existing and upcoming agents.
CNS Drugs. 2008; 22(12): 1037-45
Lyons KE, Pahwa R
Essential tremor is one of the most common movement disorders, yet the pharmacological treatments currently available have limited efficacy, being effective in only approximately 50% of patients with this disorder. The most commonly used, and generally most effective, medications for essential tremor are propranolol and primidone, administered either as monotherapy or in combination. If these medications do not provide satisfactory control of tremor, other beta-adrenoceptor antagonists, such as metoprolol or atenolol, and other antiepileptic drugs, such as topiramate or gabapentin, are often tried. In addition, benzodiazepines can be effective in some patients, particularly those with associated anxiety. There is a need for additional medications that result in greater tremor control in a larger number of patients with essential tremor. Several new drugs, including 1-octanol, sodium oxybate, dimethoxymethyl-diphenyl-barbituric acid (T-2000) and carisbamate, are currently under investigation for the treatment of essential tremor.