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

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Showing 281 - 290 of 1946 results

Tramadol (sold under the brand name Ultram) is a narcotic analgesic proposed for moderate to severe pain. Tramadol and its O-desmethyl metabolite (M1) are selective, weak OP3-receptor agonists. Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine, and noradrenaline is inhibited. The analgesic properties of Tramadol can be attributed to norepinephrine and serotonin reuptake blockade in the CNS, which inhibits pain transmission in the spinal cord. The (+) enantiomer has the higher affinity for the OP3 receptor and preferentially inhibits serotonin uptake and enhances serotonin release. The (-) enantiomer preferentially inhibits norepinephrine reuptake by stimulating alpha(2)-adrenergic receptors. Tramadol is used primarily to treat mild-severe pain, both acute and chronic. Its analgesic effects take about one hour to come into effect and 2 h to 4 h to peak after oral administration with an immediate-release formulation. On a dose-by-dose basis, tramadol has about one-tenth the potency of morphine and is approximately equally potent when compared to pethidine and codeine. The most common adverse effects of tramadol include nausea, dizziness, dry mouth, indigestion, abdominal pain, vertigo, vomiting, constipation, drowsiness, and headache. Compared to other opioids, respiratory depression and constipation are considered less of a problem with tramadol.
Bicalutamide (brand name Casodex) is an oral non-steroidal anti-androgen for prostate cancer. It is indicated for use in combination therapy with a luteinizing hormone-releasing hormone (LHRH) analog for the treatment of Stage D2 metastatic carcinoma of the prostate. Bicalutamide competitively inhibits the action of androgens by binding to cytosol androgen receptors in the target tissue. Prostatic carcinoma is known to be androgen sensitive and responds to treatment that counteracts the effect of androgen and/or removes the source of androgen. When CASODEX is combined with luteinizing hormone releasing hormone (LHRH) analog therapy, the suppression of serum testosterone induced by the LHRH analog is not affected. Bicalutamide is well-absorbed following oral administration, although the absolute bioavailability is unknown. Bicalutamide undergoes stereospecific metabolism. The S (inactive) isomer is metabolized primarily by glucuronidation. The R (active) isomer also undergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation. Both the parent and metabolite glucuronides are eliminated in the urine and feces. The S-enantiomer is rapidly cleared relative to the R-enantiomer, with the R-enantiomer accounting for about 99% of total steady-state plasma levels.

Class (Stereo):
CHEMICAL (ACHIRAL)


Conditions:

Anastrozole (marketed under the trade name Arimidex by AstraZeneca) is a drug indicated in the treatment of breast cancer in post-menopausal women. It is used both in adjuvant therapy (i.e. following surgery) and in metastatic breast cancer. It decreases the amount of estrogens that the body makes. Anastrozole belongs in the class of drugs known as aromatase inhibitors. It inhibits the enzyme aromatase, which is responsible for converting androgens (produced by women in the adrenal glands) to estrogens. The growth of many cancers of the breast is stimulated or maintained by estrogens. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol. The suppression of estrogen biosynthesis in peripheral tissues and in the cancer tissue itself can therefore be achieved by specifically inhibiting the aromatase enzyme. Anastrozole is a selective non-steroidal aromatase inhibitor. It significantly lowers serum estradiol concentrations and has no detectable effect on formation of adrenal corticosteroids or aldosterone.
Levocetirizine dihydrochloride is the R enantiomer of cetirizine hydrochloride, a racemic compound with antihistaminic properties. Levocetirizine is a third-generation non-sedative antihistamine indicated for the relief of symptoms associated with seasonal and perennial allergic rhinitis and uncomplicated skin manifestations of chronic idiopathic urticaria. It was developed from the second-generation antihistamine cetirizine. Levocetirizine was approved by the United States Food and Drug Administration on May 25, 2007 and is marketed under the brand XYZAL. Its principal effects are mediated via selective inhibition of H1 receptors. The antihistaminic activity of levocetirizine has been documented in a variety of animal and human models. In vitro binding studies revealed that levocetirizine has an affinity for the human H1-receptor 2-fold higher than that of cetirizine (Ki = 3 nmol/L vs. 6 nmol/L, respectively). The clinical relevance of this finding is unknown.
Sevoflurane is a general anesthetic that is FDA approved for the induction and maintenance of general anesthesia in adult and pediatric patients for inpatient and outpatient surgery. Sevoflurane induces a reduction in junctional conductance by decreasing gap junction channel opening times and increasing gap junction channel closing times. Sevoflurane also activates calcium dependent ATPase in the sarcoplasmic reticulum by increasing the fluidity of the lipid membrane. It also appears to bind the D subunit of ATP synthase and NADH dehydogenase and also binds to the GABA receptor. Common adverse reactions include cardiovascular: bradyarrhythmia, hypotension, gastrointestinal: nausea, vomiting, neurologic: somnolence, psychiatric: agitation, respiratory: cough, interrupted breathing and other: shivering.
Salmeterol is a long-acting beta2-adrenergic agonist. Although beta2-adrenoceptors are the predominant adrenergic receptors in bronchial smooth muscle and beta1-adrenoceptors are the predominant receptors in the heart, there are also beta2-adrenoceptors in the human heart comprising 10% to 50% of the total beta-adrenoceptors. The precise function of these is not yet established, but they raise the possibility that even highly selective beta2-agonists may have cardiac effects. It is FDA approved for the treatment of asthma, prevention of exercise-induced bronchospasm, maintenance treatment of chronic obstructive pulmonary disease. Common adverse reactions include musculoskeletal pain, headache, influenza, nasal/sinus congestion, pharyngitis, rhinitis, tracheitis/bronchitis, cough, throat irritation, viral respiratory infection. Salmeterol should be administered with extreme caution to patients being treated with monoamine oxidase inhibitors or tricyclic antidepressants, or within 2 weeks of discontinuation of such agents, because the action of salmeterol on the vascular system may be potentiated by these agents. Coadministration of salmeterol and ketoconazole was associated with more frequent increases in QTc duration compared with salmeterol and placebo administration.

Class (Stereo):
CHEMICAL (ACHIRAL)



Lamotrigine (marketed as Lamictal) is an anticonvulsant drug used in the treatment of epilepsy and bipolar disorder. The precise mechanism(s) by which lamotrigine exerts its anticonvulsant action are unknown. In animal models designed to detect anticonvulsant activity, lamotrigine was effective in preventing seizure spread in the maximum electroshock (MES) and pentylenetetrazol (scMet) tests, and prevented seizures in the visually and electrically evoked after-discharge (EEAD) tests for antiepileptic activity. Lamotrigine also displayed inhibitory properties in the kindling model in rats both during kindling development and in the fully kindled state. The relevance of these models to human epilepsy, however, is not known. One proposed mechanism of action of lamotrigine, the relevance of which remains to be established in humans, involves an effect on sodium channels. In vitro pharmacological studies suggest that lamotrigine inhibits voltage-sensitive sodium channels, thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (e.g., glutamate and aspartate). Effect of Lamotrigine on N-Methyl d-Aspartate-Receptor Mediated Activity Lamotrigine did not inhibit N-methyl d-aspartate (NMDA)-induced depolarizations in rat cortical slices or NMDA-induced cyclic GMP formation in immature rat cerebellum, nor did lamotrigine displace compounds that are either competitive or noncompetitive ligands at this glutamate receptor complex (CNQX, CGS, TCHP). The IC50 for lamotrigine effects on NMDA-induced currents (in the presence of 3 uM of glycine) in cultured hippocampal neurons exceeded 100 uM. The mechanisms by which lamotrigine exerts its therapeutic action in bipolar disorder have not been established. The mechanisms that underpin the passage of lamotrigine at the blood-brain barrier to its site of action in the brain is poorly understood.
Status:
First approved in 1994

Class (Stereo):
CHEMICAL (ABSOLUTE)

Targets:


Vinorelbine (trade name Navelbine) is a semi-synthetic vinca-alkaloid with a broad spectrum of anti-tumour activity. Vinorelbine is a mitotic spindle poison that impairs chromosomal segregation during mitosis. It blocks cells at G2/M. Microtubules (derived from polymers of tubulin) are the principal target of vinorelbine. Vinorelbine was developed by Pierre Fabre under licence from the CNRS in France. NAVELBINE (vinorelbine tartrate) as a single agent or in combination is indicated for the first line treatment of non small cell lung cancer and advanced breast cancer.
Cysteamine (trade name CYSTAGON) is a cystine-depleting agent indicated for the treatment of corneal cystine crystal accumulation in patients with cystinosis. Cystinosis is an autosomal recessive inborn error of metabolism in which the transport of cystine out of lysosomes is abnormal; in the nephropathic form, accumulation of cystine and formation of crystals damage various organs, especially the kidney, leading to renal tubular Fanconi Syndrome and progressive glomerular failure, with end-stage renal failure by the end of the first decade of life. In four studies of cystinosis patients before cysteamine was available, renal death (need for transplant or dialysis) occurred at the median age of fewer than 10 years. Patients with cystinosis also experience growth failure, rickets, and photophobia due to cystine deposits in the cornea. With time most organs are damaged, including the retina, muscles and central nervous system. Cysteamine is an aminothiol that participates within lysosomes in a thiol-disulfide interchange reaction converting cystine into cysteine and cysteine-cysteamine mixed disulfide, both of which can exit the lysosome in patients with cystinosis.
Nefazodone hydrochloride (trade name Serzone) is an antidepressant drug marketed by Bristol-Myers Squibb. Its sale was discontinued in 2003 in some countries, due to the small possibility of hepatic (liver) injury, which could lead to the need for a liver transplant, or even death. The incidence of severe liver damage is approximately 1 in 250,000 to 300,000 patient-years. On May 20, 2004, Bristol-Myers Squibb discontinued the sale of Serzone in the United States. Within the serotonergic system, nefazodone acts as an antagonist at type 2 serotonin (5-HT2) post-synaptic receptors and, like fluoxetine-type antidepressants, inhibits pre-synaptic serotonin (5-HT) reuptake. These mechanisms increase the amount of serotonin available to interact with 5-HT receptors. Within the noradrenergic system, nefazodone inhibits norepinephrine uptake minimally. Nefazodone also antagonizes alpha(1)-adrenergic receptors, producing sedation, muscle relaxation, and a variety of cardiovascular effects. Nefazodone's affinity for benzodiazepine, cholinergic, dopaminergic, histaminic, and beta or alpha(2)-adrenergic receptors is not significant.