U.S. Department of Health & Human Services Divider Arrow National Institutes of Health Divider Arrow NCATS

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Showing 1141 - 1150 of 4602 results

Sorbitol is a polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. Used as a non-stimulant laxative via an oral suspension or enema. Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. Sorbitol plays a vital step in the 'polyol pathway'. The sudden injection of extra sorbitol can ruin the equilibrium of enzymes that regulate the conversion of glucose to fructose in a process associated with the onset of diabetes and its complications. Further, the polyol pathway is involved with a complex network of metabolic activities; disruption leads to a cascade of problems (citations here, here and here) such as mitochondrial failure, cell apoptosis (cell death), and DNA fragmentation. In general, sorbitol induces cell hyperosmotic stress resulting in phosphorylation (uptake of phosphorus into cell) — an important on/off switch regulating enzymes and signaling networks.
Fludrocortisone acetate (approved as Florinef) is a synthetic adrenocortical steroid possessing very potent mineralcorticoid properties and high glucocorticoid activity. Main indications are Partial replacement therapy for primary and secondary adrenocortical insufficiency in Addison's disease and for the treatment of salt losing adrenogenital syndrome.

Class (Stereo):
CHEMICAL (ACHIRAL)



Acquired myasthenia gravis (MG) is a chronic autoimmune disorder of the neuromuscular junction, characterized clinically by muscle weakness and abnormal fatigability on exertion. Current guidelines and recommendations for MG treatment are based largely on clinical experience, retrospective analyses and expert consensus. Pyridostigmine (under the trade names Mestinon (Valeant Pharmaceuticals)), has been used as a treatment for MG for over 50 years and is generally considered safe. It is suitable as a long-term treatment in patients with generalized non-progressive milder disease, and as an adjunctive therapy in patients with severe disease who are also receiving immunotherapy. Pyridostigmine inhibits acetylcholinesterase in the synaptic cleft by competing with acetylcholine for attachment to acetylcholinesterase, thus slowing down the hydrolysis of acetylcholine, and thereby increases efficiency of cholinergic transmission in the neuromuscular junction and prolongs the effects of acetylcholine. The side effects of Mestinon are most commonly related to over dosage and generally are of two varieties, muscarinic and nicotinic. Among those in the former group are nausea, vomiting, diarrhea, abdominal cramps, increased peristalsis, increased salivation, increased bronchial secretions, miosis and diaphoresis. Nicotinic side effects are comprised chiefly of muscle cramps, fasciculation and weakness. Muscarinic side effects can usually be counteracted by atropine, but for reasons shown in the preceding section the expedient is not without danger. As with any compound containing the bromide radical, a skin rash may be seen in an occasional patient. Such reactions usually subside promptly upon discontinuance of the medication.
Chloroprocaine (Nesacaine®, Nesacaine®-MPF) is a non pyrogenic local anesthetic. Nesacaine® is indicated for the production of local anesthesia by infiltration and peripheral nerve block. It is not to be used for lumbar or caudal epidural anesthesia. Nesacaine®-MPF is indicated for the production of local anesthesia by infiltration, peripheral and central nerve block, including lumbar and caudal epidural blocks. Nesacaine® and Nesacaine®-MPF are not to be used for subarachnoid administration. Chloroprocaine (Nesacaine®, Nesacaine®-MPF), like other local anesthetics, blocks the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse and by reducing the rate of rise of the action potential. It acts mainly by inhibiting sodium influx through voltage gated sodium channels in the neuronal cell membrane of peripheral nerves. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is thus inhibited.
Methylphenidate is a CNS stimulant approved for the treatment of narcolepsy and attention deficit hyperactivity disorder. The drug is believed to bind the dopamine transporter in the presynaptic cell membrane, thereby blocking the reuptake of dopamine and causing an increase in extracellular dopamine levels.
Status:
First approved in 1955
Source:
Pyrazinamide by Merck (Merck Sharp & Dohme)
Source URL:

Class (Stereo):
CHEMICAL (ACHIRAL)


Conditions:

Pyrazinamide is indicated for the initial treatment of active tuberculosis in adults and children when combined with other antituberculous agents. (The current recommendation of the CDC for drug-susceptible disease is to use a six-month regimen for initial treatment of active tuberculosis, consisting of isoniazid, rifampin and pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months. Pyrazinamide should only be used in conjunction with other effective antituberculous agents. Pyrazinamide diffuses into M. tuberculosis, where the enzyme pyrazinamidase converts pyrazinamide to the active form pyrazinoic acid. Under acidic conditions, the pyrazinoic acid that slowly leaks out converts to the protonated conjugate acid, which is thought to diffuse easily back into the bacilli and accumulate. The net effect is that more pyrazinoic acid accumulates inside the bacillus at acid pH than at neutral pH. Pyrazinoic acid was thought to inhibit the enzyme fatty acid synthase (FAS) I, which is required by the bacterium to synthesise fatty acids. However, this theory was thought to have been discounted. However, further studies reproduced the results of FAS I inhibition as the putative mechanism first in whole cell assay of replicating M. tuberculosis bacilli which have shown that pyrazinoic acid and its ester inhibit the synthesis of fatty acids . This study was followed by in vitro assay of tuberculous FAS I enzyme that tested the activity with pyrazinamide, pyrazinoic acid and several classes of pyrazinamide analogs. Pyrazinamide and its analogs inhibited the activity of purified FAS I. It has also been suggested that the accumulation of pyrazinoic acid disrupts membrane potential and interferes with energy production, necessary for survival of M. tuberculosis at an acidic site of infection. Pyrazinoic acid has also been shown to bind to the ribosomal protein S1 (RpsA) and inhibit trans-translation. This may explain the ability of the drug to kill dormant mycobacteria
Meprobamate is a carbamate derivative used as an anxiolytic drug. Meprobamate enhances GABA-A currents, and at higher concentration, exhibits a separate channel-blocking effect that limits the magnitude of GABA(A) receptor potentiation. It is also a potent adenosine reuptake inhibitor (AdoRI), which is most likely responsible for its lesser degree of sedation compared to barbiturates. Meprobamate was withdrawn from European and Canadian markets due to its potential to cause physical and psychological dependence.
Prednisolone hemisuccinate is a prodrug of a glucocorticoid agonist prednisolone, which is marketed under trade name Prednisolut in Germany and Austria. Prednisolone hemisuccinate is used in emergency medicine to treate shock due to allergic reaction, insect and snake bites, in neurology to treat brain edema and meningitis, in transplantation medicine to reduce risk of organ refection after kidney transplane, in pneumology to treat acute asthma attack, pulmonary edema, in severe or life-threatening situation in rheumatic diseases.
Digoxin, a cardiac glycoside similar to digitoxin, is used to treat congestive heart failure and supraventricular arrhythmias due to reentry mechanisms, and to control ventricular rate in the treatment of chronic atrial fibrillation. Digoxin inhibits the Na-K-ATPase membrane pump, resulting in an increase in intracellular sodium. The sodium calcium exchanger (NCX) in turn tries to extrude the sodium and in so doing, pumps in more calcium. Increased intracellular concentrations of calcium may promote activation of contractile proteins (e.g., actin, myosin). Digoxin also acts on the electrical activity of the heart, increasing the slope of phase 4 depolarization, shortening the action potential duration, and decreasing the maximal diastolic potential.
Chlorpromazine is a psychotropic agent indicated for the treatment of schizophrenia. It also exerts sedative and antiemetic activity. Chlorpromazine has actions at all levels of the central nervous system-primarily at subcortical levels-as well as on multiple organ systems. Chlorpromazine has strong antiadrenergic and weaker peripheral anticholinergic activity; ganglionic blocking action is relatively slight. It also possesses slight antihistaminic and antiserotonin activity. Chlorpromazine acts as an antagonist (blocking agent) on different postsysnaptic receptors -on dopaminergic-receptors (subtypes D1, D2, D3 and D4 - different antipsychotic properties on productive and unproductive symptoms), on serotonergic-receptors (5-HT1 and 5-HT2, with anxiolytic, antidepressive and antiaggressive properties as well as an attenuation of extrapypramidal side-effects, but also leading to weight gain, fall in blood pressure, sedation and ejaculation difficulties), on histaminergic-receptors (H1-receptors, sedation, antiemesis, vertigo, fall in blood pressure and weight gain), alpha1/alpha2-receptors (antisympathomimetic properties, lowering of blood pressure, reflex tachycardia, vertigo, sedation, hypersalivation and incontinence as well as sexual dysfunction, but may also attenuate pseudoparkinsonism - controversial) and finally on muscarinic (cholinergic) M1/M2-receptors (causing anticholinergic symptoms like dry mouth, blurred vision, obstipation, difficulty/inability to urinate, sinus tachycardia, ECG-changes and loss of memory, but the anticholinergic action may attenuate extrapyramidal side-effects). Additionally, Chlorpromazine is a weak presynaptic inhibitor of Dopamine reuptake, which may lead to (mild) antidepressive and antiparkinsonian effects. Chlorpromazine has being marketed under the trade names Thorazine and Largactil among others. Chlorpromazine is used for treating certain mental or mood disorders (eg, schizophrenia), the manic phase of manic-depressive disorder, anxiety and restlessness before surgery, the blood disease porphyria, severe behavioral and conduct disorders in children, nausea and vomiting, and severe hiccups.

Showing 1141 - 1150 of 4602 results