Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to assess, by positron emission tomography (PET), the effect on cerebral functional activity of a new lorazepam-gamma-aminobutyric acid (GABA) conjugate [3-(4-acetamido)-butyrril lorazepam (DDS2700)]. Ten healthy volunteers were studied by PET and [18F]fluoro-deoxy-D-glucose ([18F]FDG) under baseline conditions and following the administration of DDS2700. Regional cerebral blood flow (rCBF) was measured by PET and 15O-water in three additional participants while they performed attentive tasks, before and after drug administration. DDS2700 induced a decrease in the regional cerebral metabolic rate of glucose (rCMRglu) in the thalamus (-17%), cerebellum (-11%) and caudate nucleus (-8%). The observed effects on glucose metabolism were probably related to the subjective sedation and tiredness reported by the participants. During the attentive tasks, rCBF increased in frontal and temporal regions associated with attentional processing of auditory material. These circuits were no longer active after DDS2700 administration, while rCBF increased in cingulate cortex, occipitoparietal regions, pons and cerebellum. These drug-induced activations might be directly related to intervening sleepiness and to the consequent effort in keeping attention focused on the tasks. The effects of DDS2700 on glucose metabolism at rest, and on rCBF during activation conditions, indicate a drug action on cerebral networks involved in alertness, vigilance and attention maintenance. PET assessment by [18F]FDG and water may provide complementary information in pharmacodynamic studies.
 ...
PMID:Acute effect of 3-(4-acetamido)-butyrril-lorazepam (DDS2700) on brain function assessed by PET at rest and during attentive tasks. 1133 50

Among the newly introduced antiepileptic drugs (AEDs), tiagabine (TGB) stands out as a compound with a well-understood and documented mechanism of action. It is a lipophilic derivative of nipecotic acid that blocks gamma-aminobutyric acid (GABA) reuptake by inhibition of the GAT-1 transportation system, and that has no other significant pharmacodynamic effect. The relationship between intake and blood levels is linear. Usual daily maintenance doses range from 20 to 50 mg. It is completely absorbed by the gastrointestinal tract, and its half-life is approximately 7-9 h. TGB is sensitive to enzyme induction: when coprescribed with enzyme-inducing AEDs, its half-life is shortened to 2-3 h, whereas the daily dosage has to be increased into the upper range. It should be given 3 times per day. Placebo-controlled, double-blind, add-on studies conducted in patients with drug-resistant focal epilepsies have demonstrated its efficacy and overall safety. The clinical benefits appear to persist over time. Data on its use in monotherapy are scanty. The efficacy and tolerability of TGB in the pediatric age still remain to be investigated adequately. In daily practice, TGB appears to be a safe drug, but mild to moderate side effects are frequently seen, especially during titration: these include dizziness and fatigue, and are clearly abated when the drug is absorbed during meals. Titration should be especially slow, no faster than 5 mg weekly. Clinicians also should beware of the possible occurrence of confusion, which may be misdiagnosed as absence status, a short-lasting, quickly reversible central nervous system-related side effect that appears to be correlated with the peak plasma concentrations of TGB. Particularly beneficial indications for TGB and/or AED associations including TGB have not been pointed out, but there is a hint that it works best in temporal lobe epilepsies.
 ...
PMID:Tiagabine in clinical practice. 1152 Mar 22

This review summarizes the current knowledge of the biosynthesis of neurosteroids in the human brain, the enzymes mediating these reactions, their localization and the putative effects of neurosteroids. Molecular biological and biochemical studies have now firmly established the presence of the steroidogenic enzymes cytochrome P450 cholesterol side-chain cleavage (P450SCC), aromatase, 5alpha-reductase, 3alpha-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase in human brain. The functions attributed to specific neurosteroids include modulation of gamma-aminobutyric acid A (GABAA), N-methyl-d-aspartate (NMDA), nicotinic, muscarinic, serotonin (5-HT3), kainate, glycine and sigma receptors, neuroprotection and induction of neurite outgrowth, dendritic spines and synaptogenesis. The first clinical investigations in humans produced evidence for an involvement of neuroactive steroids in conditions such as fatigue during pregnancy, premenstrual syndrome, post partum depression, catamenial epilepsy, depressive disorders and dementia disorders. Better knowledge of the biochemical pathways of neurosteroidogenesis and their actions on the brain seems to open new perspectives in the understanding of the physiology of the human brain as well as in the pharmacological treatment of its disturbances.
 ...
PMID:Neurosteroid metabolism in the human brain. 1172 Aug 89

Anticonvulsant drugs (ACs) have diverse antiseizure, psychotropic, and biochemical effects. Carbamazepine and valproate have mood-stabilizing actions, benzodiazepines and gabapentin have anxiolytic actions, lamotrigine is useful in rapid cycling and acute treatment and prophylaxis of bipolar depression, and topiramate and zonisamide can yield weight loss. Limited controlled data suggest the carbamazepine keto derivative oxcarbazepine has antimanic effects. A categorical approach to the diverse roles of ACs in bipolar disorders is proposed, using broad categories of ACs, on the basis of their predominant psychotropic profiles. Thus, some ACs have "sedating" profiles that may include sedation, cognitive difficulties, fatigue, weight gain, and possibly antimanic and/or anxiolytic effects. In contrast, some newer ACs have "activating" profiles that may include improved energy, weight loss, and possibly antidepressant and even anxiogenic effects. Still other newer ACs have novel "mixed" profiles, combining sedation and weight loss. A categorical-mechanistic extension of this approach is also presented, with hypotheses that "sedating" profiles might be related to prominent potentiation of gamma-aminobutyric acid (GABA) inhibitory neurotransmission, "activating" profiles could be related to prominent attenuation of glutamate excitatory neurotransmission, and for "mixed" profiles, sedation and weight loss might be related to concurrent GABAergic and antiglutamatergic actions, respectively. The categorical approach may have utility as an aid to clinicians in reinforcing the heterogeneity ACs, and recalling psychotropic profiles of individual ACs, but is limited as it fails to address the etiology of the heterogeneity of AC psychotropic effects. The categorical-mechanistic extension strives to address this issue, but requires systematic clinical investigation of more precise relationships between psychotropic profiles and discrete mechanisms of action to assess its merits.
 ...
PMID:The diverse roles of anticonvulsants in bipolar disorders. 1293 67

Benzodiazepines, which are gamma-aminobutyric acid-A (GABA(A)) receptor positive modulators, can block the behavioral effects of psychomotor stimulants. In the present study, the ability of oxazepam, which may have less abuse potential compared to some other benzodiazepines, to attenuate the discriminative-stimulus, subject-rated and psychomotor performance effects of d-amphetamine in humans was determined. Six healthy participants (2 female, 4 male) learned to discriminate 15 mg oral d-amphetamine. After acquiring the discrimination (i.e., > or = 80% correct responding on 4 consecutive days), the effects of d-amphetamine (0, 2.5, 5, 10 and 15 mg), alone and in combination with acutely administered oxazepam (0 and 20 mg) were assessed. d-Amphetamine alone functioned as a discriminative stimulus, produced stimulant-like subject-rated effects (e.g., increased ratings of Stimulated on a Drug-Effect Questionnaire) and enhanced psychomotor performance. Oxazepam alone increased subject ratings of sedation (e.g., increased ratings of Sluggish, Fatigued and Lazy on a Drug-Effect Questionnaire) and impaired psychomotor performance. Oxazepam alone did not occasion d-amphetamine-like discriminative-stimulus effects, and had no effect on the discriminative-stimulus or subject-rated effects of d-amphetamine when given in combination. The results of this experiment are discordant with previous research and suggest that benzodiazepines differ in their ability to modulate the behavioral effects of d-amphetamine.
 ...
PMID:Oxazepam does not modulate the behavioral effects of d-amphetamine in humans. 1618 53

Fatigue is one of the most common non-specific symptoms associated with several disease states including liver diseases. Recently, it was reported that levels of progesterone metabolites such as allopregnanolone (3alpha,5alpha-tetrahydroprogesterone; 3alpha,5alpha-THP) and isopregnanolone (3beta,5alpha-THP) were increased in plasma of patients with chronic fatigue syndrome. We hypothesize that THP metabolites might be associated with fatigue commonly observed in chronic liver diseases. We evaluated fatigue scores and plasma levels of five progesterone metabolites in 16 patients with primary biliary cirrhosis (PBC), 12 patients with chronic hepatitis C (CHC) and 11 age-matched controls. The fatigue impact scale (FIS) ratio was significantly increased (P < 0.01) in patients with PBC and CHC compared to controls. Plasma levels of 3alpha,5alpha-THP and pregnanolone (3alpha,5beta-THP) were significantly increased in PBC and CHC patients. The other progesterone metabolites, i.e. 3beta,5alpha-THP, 3beta,5beta-THP and 3alpha,5alpha-tetrahydrodeoxycorticosterone were either undetectable or detected only in some patients. Plasma levels of 3alpha,5alpha-THP and 3alpha,5beta-THP were found to be significantly higher in patients with fatigue (P < 0.05), while those of patients without fatigue were not significantly different from controls. Both 3alpha,5alpha-THP and 3alpha,5beta-THP are positive allosteric modulators of the gamma-aminobutyric acid type A (GABA-A) receptor and readily cross the blood-brain barrier. The present preliminary findings suggest that increased inhibition through GABA-A receptors due to the accumulation of neuroinhibitory steroids may represent an important pathophysiological mechanism of fatigue in chronic liver diseases.
 ...
PMID:Neuroactive steroids and fatigue severity in patients with primary biliary cirrhosis and hepatitis C. 1828 71

The objective of these studies was to evaluate the efficacy and tolerability of tiagabine, a selective gamma-aminobutyric acid reuptake inhibitor, in adult patients with generalized anxiety disorder (GAD). Patients with a diagnosis of GAD were enrolled in 1 of 3 randomized, placebo-controlled, 10-week studies. In each study, tiagabine was taken twice daily in divided doses--4, 8, or 12 mg/d in a fixed-dose study and 4-16 mg/d in two flexible-dose trials. The primary efficacy measure was the change from baseline in the 14-item Hamilton Rating Scale for Anxiety (HAM-A) total score at the final visit (last observation carried forward). Additional measures included change from baseline in the anxiety subscale of the Hospital Anxiety and Depression Scale, the Sheehan Disability Scale, and Clinical Global Impressions-Improvement scale. Tolerability was assessed via spontaneous reports as well as rating scales throughout the study period. In all 3 studies, there was no significant differentiation from placebo on the primary measure (change in HAM-A) for any tiagabine dose (P > 0.05). In the 2 flexible-dose studies, the tiagabine group showed improvements over time in the HAM-A that reached significance only in those patients who completed 10 weeks of treatment (study 2, P = 0.018; study 3, P = 0.036). The most common adverse events were dizziness, headache, nausea, fatigue, and somnolence. In conclusion, the results of these studies do not support the efficacy of tiagabine in adult patients with GAD.
 ...
PMID:Tiagabine in adult patients with generalized anxiety disorder: results from 3 randomized, double-blind, placebo-controlled, parallel-group studies. 1848 Jun 88

Tiagabine hydrochloride (TGB) is a selective gamma-aminobutyric acid (GABA) reuptake inhibitor. TGB is effective as an add-on medication in adults and children 12 years and older in the treatment of partial seizures. Results of nonrandomized add-on trials with TGB show treatment success with seizure reduction of at least 50% in 33% to 46% of patients. In newly diagnosed patients with partial epilepsy, TGB monotherapy was as effective as carbamazepine. Comedication with TGB elevates the risk of nonconvulsive status (7.8% vs 2.7% without TGB). The most common side effects include dizziness/lightheadedness, asthenia/lack of energy and somnolence. TGB has no negative effects on cognition; it does not increase the risk of fractures or rash. TGB may interfere with color perception. TGB presents an intermediate risk for depression in patients with epilepsy (approximately 4%). Regarding the risk of overdose, 96-680 mg TGB (mean 224 mg) caused seizures or coma. TGB is an antiepileptic drug exhibiting a specific anticonvulsive mechanism of action, the efficacy of which is relatively low when used in comedication. Critical side effects, such as the induction of nonconvulsive status epilepticus, further limit its use.
 ...
PMID:Tiagabine: efficacy and safety in partial seizures - current status. 1904 17

Fibromyalgia (FM) is a common, chronic pain disorder with unknown etiology, characterized by widespread musculoskeletal pain and tenderness, and accompanied by several other symptoms such as sleep disturbance, fatigue, and mood disorders. Pregabalin is the first drug approved for the treatment of FM. Pregabalin has analgesic, anticonvulsant, and anxiolytic activity and has earlier demonstrated efficacy in the management of neuropathic pain associated with diabetic peripheral neuropathy, postherpetic neuralgia, and as adjuvant therapy for adult patients with partial onset seizures. Pregabalin, a lipophilic gamma-aminobutyric acid (GABA) analog, is alpha(2)delta-1 ligand that binds to, and modulates, voltage-gated calcium channels. This modulation is characterized by a reduction of the excessive neurotransmitter release that is observed in certain neurological and psychotic disorders. Several randomized, double-blind, placebo-controlled studies have demonstrated that pregabalin has been effective in pain management, improving sleep quality and fatigue, as well as in several domains of health related quality of life. Because of mild to moderate adverse effects it can be considered a well-tolerated therapy for FM.
 ...
PMID:New treatment options in the management of fibromyalgia: role of pregabalin. 1933 59

Patients with neurologic disorders commonly experience sleep dysfunction and psychiatric disorders. The most common sleep dysfunction is insomnia, which is a primary symptom in 30% to 90% of psychiatric disorders. Insomnia and fatigue are prominent symptoms of anxiety disorders and major depression that may occur in patients who are treated but have residual sleep dysfunction. Anxiety and depressive disorders account for 40% to 50% of all cases of chronic insomnia. It is also recognized that primary insomnia and other primary sleep disorders produce symptoms that are similar to those reported by patients with psychiatric disorders. A clinician must judge whether sleep deprivation causes mood disturbance or whether depressive or anxiety disorder represents the primary reason for sleep dysfunction. When insomnia is comorbid with mild to moderate depression, therapy should begin with bedtime dosing of sedating antidepressants such as mirtazapine, nefazodone, or tricyclic antidepressants, which are preferred because of their sedative effects. Often side effects limit their usefulness. Intervention for chronic insomnia is similar in nonpsychiatric and psychiatric patients. Behavioral therapies, particularly multicomponent cognitive-behavioral therapy, and lifestyle changes show significant long-term efficacy as treatments for chronic insomnia. The most studied pharmacologic agents to treat insomnia are sedative hypnotic agents, particularly those that are active through the benzodiazepine receptor-GABA (gamma-aminobutyric acid) complex, such as benzodiazepines, eszopiclone, zaleplon, and zolpidem. Melatonin and the melatonin-receptor agonist ramelteon have not had adequate study in psychiatric patients to define their use, but small studies suggest benefit. Prescription of adjunctive trazodone (50-150 mg) is a common clinical practice to treat comorbid insomnia during antidepressant therapy, but published data are surprisingly limited, considering its frequent use. Although there has been insufficient research on the use of atypical antipsychotic agents in severe insomnia, psychiatrists use quetiapine, olanzapine, or others to lessen agitation that disrupts sleep. When insomnia or hypersomnia continue even as mood, anxiety, or thought disorders improve with standard therapy, the physician should consider the potential presence of underlying sleep disorders.
 ...
PMID:Treatment of sleep dysfunction and psychiatric disorders. 1974 1


<< Previous 1 2 3 Next >>