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

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Showing 201 - 210 of 21518 results

Olanzapine is a novel antipsychotic agent marketed by Lilly & Co. It has a pleotrophic pharmacology and affects dopaminergic, serotonergic, muscarinic and adrenergic activities. Olanzapine is used to treat the symptoms of psychotic conditions such as schizophrenia and bipolar disorder (manic depression) in adults and children who are at least 13 years old. Olanzapine is sometimes used together with other antipsychotic medications or antidepressants. The mechanism of action of olanzapine, as with other drugs having efficacy in schizophrenia, is unknown. However, it has been proposed that this drug’s efficacy in schizophrenia is mediated through a combination of dopamine and serotonin type 2 (5HT2) antagonism. The mechanism of action of olanzapine in the treatment of acute manic or mixed episodes associated with bipolar I disorder is unknown. Olanzapine treatment led to rapid phosphorylation of kinases from all three pathways in PC12 cells. Phosphorylation of Akt was blocked with selective inhibitors (wortmannin and LY294002), which implicates phosphoinositide 3-kinase (PI3K) in the signaling cascade. Short-term mitogenic effects of olanzapine were abolished with a selective inhibitor of Akt, but not by inhibition of the ERK pathway. Olanzapine is metabolized by the cytochrome P450 system; principally by isozyme 1A2 and to a lesser extent by 2D6. By these mechanisms more than 40% of the oral dose, on average, is removed by the hepatic first-pass effect. Drugs or agents that increase the activity of CYP1A2, notably tobacco smoke, may significantly increase hepatic first-pass clearance of Olanzapine; conversely, drugs which inhibit 1A2 activity (examples: Ciprofloxacin, Fluvoxamine) may reduce Olanzapine clearance. The most common side effects appear to be somnolence and weight gain. About 11% of patients gain weight -especially if on a high starting dose and if they were underweight pre-treatment. Sexual dysfunction is a problem for many patients, although sexual dysfunction in schizophrneia does not appear to be primarily attributable to drugs.
Ritonavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Ritonavir binds to the protease active site and inhibits the activity of the enzyme. It is FDA approved for the treatment of HIV-1 infection. In patients receiving medications metabolized by CYP3A or initiation of medications metabolized by CYP3A in patients already receiving Ritonavir, may increase plasma concentrations of medications metabolized by CYP3A. The most frequently reported adverse drug reactions among patients receiving Ritonavir alone or in combination with other antiretroviral drugs were gastrointestinal (including diarrhea, nausea, vomiting, abdominal pain (upper and lower)), neurological disturbances (including paresthesia and oral paresthesia), rash, and fatigue/asthenia.
Docetaxel was protected by patents (U.S. patent and European patent) which were owned by Sanofi-Aventis, and so was available only under the Taxotere brand name internationally. The European patent expired in 2010. Docetaxel is a clinically well-established anti-mitotic chemotherapy medication used for the treatment of patients with locally advanced or metastatic breast cancer after failure of prior chemotherapy. Also used as a single agent in the treatment of patients with locally advanced or metastatic non-small cell lung cancer after failure of prior platinum-based chemotherapy. It is also used in combination with prednisone, in the treatment of patients with androgen independent (hormone refractory) metastatic prostate cancer. Furthermore, docetaxel has uses in the treatment of gastric adenocarcinoma and head and neck cancer. Docetaxel interferes with the normal function of microtubule growth. Whereas drugs like colchicine cause the depolymerization of microtubules in vivo, docetaxel arrests their function by having the opposite effect; it hyper-stabilizes their structure. This destroys the cell's ability to use its cytoskeleton in a flexible manner. Specifically, docetaxel binds to the β-subunit of tubulin. Tubulin is the "building block" of mictotubules, and the binding of docetaxel locks these building blocks in place. The resulting microtubule/docetaxel complex does not have the ability to disassemble. This adversely affects cell function because the shortening and lengthening of microtubules (termed dynamic instability) is necessary for their function as a transportation highway for the cell. Chromosomes, for example, rely upon this property of microtubules during mitosis. Further research has indicated that docetaxel induces programmed cell death (apoptosis) in cancer cells by binding to an apoptosis stopping protein called Bcl-2 (B-cell leukemia 2) and thus arresting its function.

Class (Stereo):
CHEMICAL (ACHIRAL)



Nilutamide is an antineoplastic hormonal agent primarily used in the treatment of prostate cancer. Nilutamide is a pure, nonsteroidal anti-androgen with affinity for androgen receptors (but not for progestogen, estrogen, or glucocorticoid receptors). Consequently, Nilutamide blocks the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. Prostate cancer is mostly androgen-dependent and can be treated with surgical or chemical castration. To date, antiandrogen monotherapy has not consistently been shown to be equivalent to castration. The relative binding affinity of nilutamide at the androgen receptor is less than that of bicalutamide, but similar to that of hydroxuflutamide. Nilutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. This blockade of androgen receptors may result in growth arrest or transient tumor regression through inhibition of androgen-dependent DNA and protein synthesis. Nilutamide is used in combination with surgical castration for the treatment of metastatic prostate cancer involving distant lymph nodes, bone, or visceral organs (Stage D2). Nilutamide is sold under the brand names Nilandron (US), Anandron (CA)).
Miglitol, an oral alpha-glucosidase inhibitor, is a desoxynojirimycin derivative that delays the digestion of ingested carbohydrates, thereby resulting in a smaller rise in blood glucose concentration following meals. As a consequence of plasma glucose reduction, miglitol reduce levels of glycosylated hemoglobin in patients with Type II (non-insulin-dependent) diabetes mellitus. Systemic nonenzymatic protein glycosylation, as reflected by levels of glycosylated hemoglobin, is a function of average blood glucose concentration over time. Because its mechanism of action is different, the effect of miglitol to enhance glycemic control is additive to that of sulfonylureas when used in combination. In addition, miglitol diminishes the insulinotropic and weight-increasing effects of sulfonylureas. Miglitol has minor inhibitory activity against lactase and consequently, at the recommended doses, would not be expected to induce lactose intolerance. In contrast to sulfonylureas, miglitol does not enhance insulin secretion. The antihyperglycemic action of miglitol results from a reversible inhibition of membrane-bound intestinal a-glucoside hydrolase enzymes. Membrane-bound intestinal a-glucosidases hydrolyze oligosaccharides and disaccharides to glucose and other monosaccharides in the brush border of the small intestine. In diabetic patients, this enzyme inhibition results in delayed glucose absorption and lowering of postprandial hyperglycemia. Miglitol is used as an adjunct to diet to improve glycemic control in patients with non-insulin-dependent diabetes mellitus (NIDDM) whose hyperglycemia cannot be managed with diet alone.
Gemcitabine is a nucleoside analog used as chemotherapy. It is marketed as Gemzar® by Eli Lilly and Company. Gemcitabine inhibits thymidylate synthetase, leading to inhibition of DNA synthesis and cell death. Gemcitabine is a prodrug so activity occurs as a result of intracellular conversion to two active metabolites, gemcitabine diphosphate and gemcitabine triphosphate by deoxycitidine kinase. Gemcitabine diphosphate also inhibits ribonucleotide reductase, the enzyme responsible for catalyzing synthesis of deoxynucleoside triphosphates required for DNA synthesis. Finally, Gemcitabine triphosphate (diflurorodeoxycytidine triphosphate) competes with endogenous deoxynucleoside triphosphates for incorporation into DNA. Gemcitabine is indicated for the treatment of advanced ovarian cancer that has relapsed at least 6 months after completion of platinum-based therapy; metastatic ovarian cancer; inoperable, locally advanced (Stage IIIA or IIIB), or metastatic (Stage IV) non-small cell lung cancer; and locally advanced (nonresectable Stage II or Stage III) or metastatic (Stage IV) adenocarcinoma of the pancreas.
Topiramate is an anticonvulsant indicated in the treatment of epilepsy and migraine. Topiramate enhances GABA-activated chloride channels. In addition, topiramate inhibits excitatory neurotransmission, through actions on kainate and AMPA receptors. There is evidence that topiramate has a specific effect on GluR5 kainate receptors. It is also an inhibitor of carbonic anhydrase, particular subtypes II and IV, but this action is weak and unlikely to be related to its anticonvulsant actions, but may account for the bad taste and the development of renal stones seen during treatment. Its possible effect as a mood stabilizer seems to occur before anticonvulsant qualities at lower dosages. Topiramate inhibits maximal electroshock and pentylenetetrazol-induced seizures as well as partial and secundarily generalized tonic-clonic seizures in the kindling model, findings predective of a broad spectrum of antiseizure activities clinically. The precise mechanism of action of topiramate is not known. However, studies have shown that topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel blocking action. Topiramate also augments the activity of the neurotransmitter gamma-aminobutyrate (GABA) at some subtypes of the GABAAreceptor (controls an integral chloride channel), indicating a possible mechanism through potentiation of the activity of GABA. Topiramate also demonstrates antagonism of the AMPA/kainate subtype of the glutamate excitatory amino acid receptor. It also inhibits carbonic anhydrase (particularly isozymes II and IV), but this action is weak and unlikely to be related to its anticonvulsant actions. Topiramate is used for the treatment and control of partial seizures and severe tonic-clonic (grand mal) seizures and also for the prevention of migraine headaches. In children it is also used for treatment of Lennox-Gastaut syndrome. Topiramate is sold under the brand name Topamax. A combination product containing phentermine and topiramate extended-release called QSYMIA® is indicated for the management of obesity.
Status:
First approved in 1996

Class (Stereo):
CHEMICAL (ACHIRAL)


Conditions:

Acitretin is all-Trans-9-(4-methoxy-2, 3, 6¬ trimethylphenyl)-three, 7-dimethyl-2, 4, 6, 8-nonatetraenoic acid. It is a metabolite of exterminate and is related to both retinoic acid and retinol (vitamin A). It is taken orally, and is typically used for psoriasis. The mechanism of action of is unknown. However it is believed to work by targeting specific receptors (retinoid receptors such as RXR and RAR) in the skin, which help normalize the growth cycle of skin cells. Studies on nuclear retinoic acid receptors have shown that acitretin activates all 3 receptor subtypes (RAR-alpha, -beta, and -gamma) without measurable receptor binding; this paradox remains unexplained.

Class (Stereo):
CHEMICAL (RACEMIC)


Conditions:

Nisoldipine is a 1,4-dihydropyridine derivative with an outstanding vascular selectivity. As a specific calcium antagonist, it shortens the action potential and causes electromechanical uncoupling in ventricular myocardium. However, this effect, resulting in a negative inotropic action, appears at 100–1000 times higher concentrations of nisoldipine in comparison with its inhibition of calcium-dependent vascular contractions. Detailed analyses of pharmacological effects revealed additional properties such as enhancement of sodium excretion, an interaction with the reninangiotensin-aldosterone system and a protective effect against acute renal ischaemia, that may contribute to its therapeutic efficacy. Nisoldipine was developed at Bayer then licensed to Zeneca and marketed in the United States as SULAR. SULAR is indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents. The mechanism of the therapeutic effect of nisoldipine is complex. It involves a decrease of the total peripheral vascular resistance (reduction of afterload) and an increase in coronary blood flow. Moreover, nisoldipine obviously normalises the impaired volume homoeostasis by improving renal function and thus reduces the need for activation of the ANP system. In the advanced stages of hypertension, nisoldipine prevents deleterious calcium overload and the resulting tissue damage.
Nalmefene is the first medication approved for alcoholism with the primary goal of reducing alcohol intake in an as needed approach. Nalmefene received a marketing authorization valid throughout the European Union on February 25, 2013 and is under development in Asia. Nalmefene is an opioid system modulator with a distinct μ, δ, and κ receptor profile. In vitro studies have demonstrated that Nalmefene is a selective opioid receptor ligand with antagonist activity at the μ and δ receptors and partial agonist activity at the κ receptor. In vivo studies have demonstrated that nalmefene reduces alcohol consumption, possibly by modulating cortico-mesolimbic functions. In the US, immediate-release injectable nalmefene was approved in 1995 as an antidote for opioid overdose. It was sold under the trade name Revex. The product was discontinued by its manufacturer around 2008. Currently Nalmefene is sold under the trade name Selincro. Selincro is indicated for the reduction of alcohol consumption in adult patients with alcohol dependence who have a high drinking-risk level, without physical withdrawal symptoms and who do not require immediate detoxification.