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

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Showing 1021 - 1030 of 167129 results

Dicloxacillin sodium USP is a semisynthetic antibiotic substance which resists destruction by the enzyme penicillinase (beta-lactamase). It is monosodium (2S,5R,6R)-6-[3-(2,6-dichlorophenyl)-5-methyl-4- isoxazolecarboxamido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo [3.2.0]heptane-2-carboxylate monohydrate. Like other β-lactam antibiotics, dicloxacillin acts by inhibiting the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell wall of Gram-positive bacteria. Dicloxacillin is administered orally via capsule form or powder for reconstitution.
Levonorgestrel (LNG) is a synthetic progestational hormone with actions similar to those of progesterone and about twice as potent as its racemic or (+-)-isomer (norgestrel). It is used for contraception, control of menstrual disorders, and treatment of endometriosis. It is usually supplied in a racemic mixture (Norgestrel, 6533-00-2). Only the levonorgestrel isomer is active. Within an Intrauterine device (IUD), sold as Mirena among others, it is effective for long term prevention of pregnancy. The local mechanism by which continuously released LNG enhances contraceptive effectiveness of Mirena has not been conclusively demonstrated. Studies of Mirena and similar LNG IUS prototypes have suggested several mechanisms that prevent pregnancy: thickening of cervical mucus preventing passage of sperm into the uterus, inhibition of sperm capacitation or survival, and alteration of the endometrium. Mirena has mainly local progestogenic effects in the uterine cavity. The high local levels of levonorgestrel lead to morphological changes including stromal pseudodecidualization, glandular atrophy, a leukocytic infiltration and a decrease in glandular and stromal mitoses. Ovulation is inhibited in some women using Mirena. In a 1-year study, approximately 45% of menstrual cycles were ovulatory, and in another study after 4 years, 75% of cycles were ovulatory. There has been much debate regarding levonorgestrel emergency contraception's (LNG-EC's) method of action since 1999 when the Food and Drug Administration first approved its use. Proponents of LNG-EC have argued that they have moral certitude that LNG-EC works via a non-abortifacient mechanism of action, and claim that all the major scientific and medical data consistently support this hypothesis. However, newer medical data serve to undermine the consistency of the non-abortifacient hypothesis and instead support the hypothesis that preovulatory administration of LNG-EC has significant potential to work via abortion. The implications of the newer data have important ramifications for medical personnel, patients, and both Catholic and non-Catholic emergency room protocols. In the future, technology such as the use of early pregnancy factor may have the potential to quantify how frequently preovulatory LNG-EC works via abortion. The latest scientific and medical evidence now demonstrates that levonorgestrel emergency contraception theoretically works via abortion quite often. The implications of the newer data have important ramifications for medical personnel, patients, and both Catholic and non-Catholic emergency room rape protocols.

Class (Stereo):
CHEMICAL (ACHIRAL)

Targets:


Deferoxamine (brand name Desferal) an iron chelator, is a drug for the treatment of acute iron intoxication and of chronic iron overload due to transfusion-dependent anemias. Deferoxamine chelates iron by forming a stable complex that prevents the iron entering into further chemical reactions. However, drug may cause hypersensitivity reactions, systemic allergic reactions, and cardiovascular, hematologic and neurological adverse reactions. Serious adverse reactions include significant hypotension and marked body weight loss. Principally plasma enzymes metabolize deferoxamine, but the pathways have not yet been defined. The chelate is readily soluble in water and passes easily through the kidney, giving the urine a characteristic reddish color. Some is also excreted in the feces via the bile.
Ethacrynic acid is a monosulfonamyl loop or high ceiling diuretic. Ethacrynic acid acts on the ascending limb of the loop of Henle and on the proximal and distal tubules. Urinary output is usually dose dependent and related to the magnitude of fluid accumulation. Water and electrolyte excretion may be increased several times over that observed with thiazide diuretics, since ethacrynic acid inhibits reabsorption of a much greater proportion of filtered sodium than most other diuretic agents. Therefore, ethacrynic acid is effective in many patients who have significant degrees of renal insufficiency. Ethacrynic acid has little or no effect on glomerular filtration or on renal blood flow, except following pronounced reductions in plasma volume when associated with rapid diuresis. Ethacrynic acid inhibits symport of sodium, potassium, and chloride primarily in the ascending limb of Henle, but also in the proximal and distal tubules. This pharmacological action results in excretion of these ions, increased urinary output, and reduction in extracellular fluid. Diuretics also lower blood pressure initially by reducing plasma and extracellular fluid volume; cardiac output also decreases, explaining its antihypertensive action. Eventually, cardiac output returns to normal with an accompanying decrease in peripheral resistance. Its mode of action does not involve carbonic anhydrase inhibition. Ethacrynic acid is indicated for the treatment of high blood pressure and edema caused by diseases like congestive heart failure, liver failure, and kidney failure.

Class (Stereo):
CHEMICAL (ACHIRAL)



Hydroxyurea is an oral antimetabolite; inhibits ribonucleotide reductase and DNA synthesis. It is used for resistant chronic myeloid leukemia, locally advanced squamous cell carcinomas of the head and neck (excluding lip) in combination with concurrent chemoradiation, and to reduce the frequency of painful crises and the need for blood transfusions in patients with sickle cell anemia with recurrent moderate to severe painful crises. Hydroxyurea, a myelosuppressive agent, is the only effective drug proven to reduce the frequency of painful episodes. It raises the level of HbF and the haemoglobin level. It usually decreases the rate of painful episodes by 50%. It was first tested in sickle cell disease in 1984. It also decreases the rate of ACS episodes and blood transfusions by ~50 % in adults. It was developed as an anticancer drug and has been used to treat myeloproliferative syndromes-leukemia, melanoma, and ovarian cancer. It was approved for use by FDA in adults. Side effects includes neutropenia, bone marrow suppression, elevation of hepatic enzymes, anorexia, nausea, vomiting and infertility.
Haloperidol is a phenyl-piperidinyl-butyrophenone that is used primarily to treat schizophrenia and other psychoses. It is also used in schizoaffective disorder, delusional disorders, ballism, and Tourette syndrome (a drug of choice) and occasionally as adjunctive therapy in mental retardation and the chorea of Huntington disease. It is a potent antiemetic and is used in the treatment of intractable hiccups. Haloperidol also exerts sedative and antiemetic activity. Haloperidol principal pharmacological effects are similar to those of piperazine-derivative phenothiazines. The drug has action at all levels of the central nervous system-primarily at subcortical levels-as well as on multiple organ systems. Haloperidol has strong antiadrenergic and weaker peripheral anticholinergic activity; ganglionic blocking action is relatively slight. It also possesses slight antihistaminic and antiserotonin activity. The precise mechanism whereby the therapeutic effects of haloperidol are produced is not known, but the drug appears to depress the CNS at the subcortical level of the brain, midbrain, and brain stem reticular formation. Haloperidol seems to inhibit the ascending reticular activating system of the brain stem (possibly through the caudate nucleus), thereby interrupting the impulse between the diencephalon and the cortex. The drug may antagonize the actions of glutamic acid within the extrapyramidal system, and inhibitions of catecholamine receptors may also contribute to haloperidol's mechanism of action. Haloperidol may also inhibit the reuptake of various neurotransmitters in the midbrain, and appears to have a strong central antidopaminergic and weak central anticholinergic activity. The drug produces catalepsy and inhibits spontaneous motor activity and conditioned avoidance behaviours in animals. The exact mechanism of antiemetic action of haloperidol has also not been fully determined, but the drug has been shown to directly affect the chemoreceptor trigger zone (CTZ) through the blocking of dopamine receptors in the CTZ. Haloperidol is marketed under the trade name Haldol among others.

Class (Stereo):
CHEMICAL (ACHIRAL)



Mefenamic acid is a non-steroidal anti-inflammatory agent with analgesic, anti-inflammatory, and antipyretic properties. It is used for the treatment of mild to moderate pain, including menstrual pain, inflammation, and fever. Clinical use of mefenamic acid has generally declined in an era where other NSAID use has flourished. While having modes of action and general toxicities similar to other NSAIDs, mefenamic acid, as a member of the fenamates, nevertheless possesses some unique in vitro effects that have the potential to distinguish this agent from others. Use of this drug remains relevant for pain syndromes and some gynecological disorders, albeit with considerable competition from other NSAIDs. New basic science has considerably improved the understanding of the biochemistry of mefenamic acid. As well as maintaining its use in traditional settings, there is a tremendous potential for expanding the application of mefenamic acid to niche roles. Mefenamic acid binds the prostaglandin synthetase receptors COX-1 and COX-2, inhibiting the action of prostaglandin synthetase. Mefenamic acid concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because mefenamic acid is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues.
Status:
First approved in 1967
Source:
PROPRANOLOL HYDROCHLORIDE by BAXTER HLTHCARE CORP
Source URL:

Class (Stereo):
CHEMICAL (RACEMIC)



Propranolol is a nonselective, beta-adrenergic receptor-blocking agent possessing no other autonomic nervous system activity. At dosages greater than required for beta blockade, propranolol also exerts a quinidine-like or anesthetic-like membrane action, which affects the cardiac action potential. Among the factors that may be involved in contributing to the antihypertensive action include: (1) decreased cardiac output, (2) inhibition of renin release by the kidneys, and (3) diminution of tonic sympathetic nerve outflow from vasomotor centers in the brain. Although total peripheral resistance may increase initially, it readjusts to or below the pretreatment level with chronic use of propranolol. Effects of propranolol on plasma volume appear to be minor and somewhat variable. In angina pectoris, propranolol generally reduces the oxygen requirement of the heart at any given level of effort by blocking the catecholamine-induced increases in the heart rate, systolic blood pressure, and the velocity and extent of myocardial contraction. Propranolol may increase oxygen requirements by increasing left ventricular fiber length, end diastolic pressure, and systolic ejection period. The net physiologic effect of beta-adrenergic blockade is usually advantageous and is manifested during exercise by delayed onset of pain and increased work capacity. Propranolol exerts its antiarrhythmic effects in concentrations associated with beta-adrenergic blockade, and this appears to be its principal antiarrhythmic mechanism of action. In dosages greater than required for beta blockade, propranolol also exerts a quinidine-like or anesthetic-like membrane action, which affects the cardiac action potential. The significance of the membrane action in the treatment of arrhythmias is uncertain. The mechanism of the anti-migraine effect of propranolol has not been established. Propranolol is indicated in the management of hypertension. It may be used alone or used in combination with other antihypertensive agents, particularly a thiazide diuretic. Also is indicated to decrease angina frequency and increase exercise tolerance in patients with angina pectoris; for the prophylaxis of common migraine headache. In addition, is used to improve NYHA functional class in symptomatic patients with hypertrophic subaortic stenosis. Due to the high penetration across the blood–brain barrier, propranolol causes sleep disturbances such as insomnia and vivid dreams, and nightmares. Dreaming (rapid eye movement sleep, REM) was reduced and increased awakening.
Status:
First approved in 1967

Class (Stereo):
CHEMICAL (ACHIRAL)



Protriptyline (trade name Vivactil) is a tricyclic antidepressant, indicated for the treatment of depression. Protriptyline acts by decreasing the reuptake of norepinephrine and to a lesser extent serotonin (5-HT) in the brain. Tricyclic antidepressants act to change the balance of naturally occurring chemicals in the brain that regulate the transmission of nerve impulses between cells. Protriptyline increases the concentration of norepinephrine and serotonin (both chemicals that stimulate nerve cells) and, to a lesser extent, blocks the action of another brain chemical, acetylcholine. The therapeutic effects of protriptyline, like other antidepressants, appear slowly. Maximum benefit is often not evident for at least two weeks after starting the drug. Protriptyline is used primarily to treat depression and to treat the combination of symptoms of anxiety and depression. Like most antidepressants of this chemical and pharmacological class, protriptyline has also been used in limited numbers of patients to treat panic disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, enuresis, eating disorders such as bulimia nervosa, cocaine dependency, and the depressive phase of bipolar disorder (manic-depressive) disorder. It has also been used to support smoking cessation programs. Like all tricyclic antidepressants, protriptyline should be used cautiously and with close physician supervision. This is especially so in the elderly, or people who have benign prostatic hypertrophy (enlarged prostate gland), or urinary retention, or glaucoma, especially angle-closure glaucoma (the most severe form). Before starting treatment, people should discuss the relative risks and benefits of treatment with their doctors to help determine if protriptyline is the right antidepressant for them. A common problem with tricyclic antidepressants is sedation (drowsiness, lack of physical and mental alertness), but protriptyline is considered the least sedating agent among this class of agents. Its side effects are especially noticeable early in therapy. In most people, early tricyclic side-effects decrease or disappear entirely with time, but, until then, patients taking protriptyline should take care to assess which side-effects occur in them and should not perform hazardous activities requiring mental acuity or coordination. The side-effects are increased when protriptyline is taken with central nervous system depressants, such as alcoholic beverages, sleeping medications, other sedatives, or antihistamines, as well as with other antidepressants including SSRIs, SNRIs or monoamine oxidase Inhibitors.
Doxycycline hyclate (Vibramycin, Periostat, Vibra-Tabs) is salt of tetracycline antibiotic Doxycycline, that used to treat many kinds of infections, like dental, skin, respiratory, and urinary tract infections. It also treats acne, Lyme disease, malaria, and certain sexually transmitted diseases. Doxycycline hyclate is a light-yellow crystalline powder which is soluble in water, while doxycycline monohydrate is very slightly soluble in water. Doxycycline is bacteriostatic, inhibiting bacterial protein synthesis due to disruption of transfer RNA and messenger RNA at ribosomal sites. Doxycycline hyclate is indicated for use in the treatment of chronic adult periodontitis for a gain in clinical attachment, reduction in probing depth, and reduction in bleeding on probing.

Showing 1021 - 1030 of 167129 results