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

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Showing 71 - 80 of 1923 results

Quinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent (Ia) in the heart. It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree. The drug causes increased action potential duration, as well as a prolonged QT interval. Like all other class I antiarrhythmic agents, quinidine primarily works by blocking the fast inward sodium current (INa). Quinidine's effect on INa is known as a 'use-dependent block'. This means at higher heart rates, the block increases, while at lower heart rates, the block decreases. The effect of blocking the fast inward sodium current causes the phase 0 depolarization of the cardiac action potential to decrease (decreased Vmax). Quinidine also blocks the slowly inactivating, tetrodotoxin-sensitive Na current, the slow inward calcium current (ICA), the rapid (IKr) and slow (IKs) components of the delayed potassium rectifier current, the inward potassium rectifier current (IKI), the ATP-sensitive potassium channel (IKATP) and Ito. Quinidine is also an inhibitor of the cytochrome P450 enzyme 2D6 and can lead to increased blood levels of lidocaine, beta blockers, opioids, and some antidepressants. Quinidine also inhibits the transport protein P-glycoprotein and so can cause some peripherally acting drugs such as loperamide to have central nervous system side effects, such as respiratory depression if the two drugs are coadministered. Quinidine can cause thrombocytopenia, granulomatous hepatitis, myasthenia gravis, and torsades de pointes, so is not used much today. Torsades can occur after the first dose. Quinidine-induced thrombocytopenia (low platelet count) is mediated by the immune system and may lead to thrombocytic purpura. A combination of dextromethorphan and quinidine has been shown to alleviate symptoms of easy laughing and crying (pseudobulbar affect) in patients with amyotrophic lateral sclerosis and multiple sclerosis. This drug is marketed as Nuedexta in the United States. Intravenous quinidine is also indicated for the treatment of Plasmodium falciparum malaria. However, quinidine is not considered the first-line therapy for P. falciparum. The recommended treatments for P. falciparum malaria, according to the Toronto Notes 2008, are a combination of either quinine and doxycycline or atovaquone and proguanil (Malarone). The drug is also effective for the treatment of atrial fibrillation in horses.
Status:
First marketed in 1921
Source:
Quinine Dihydrochloride U.S.P.
Source URL:

Class (Stereo):
CHEMICAL (ABSOLUTE)



Quinine soluble salts possess the extremely bitter taste, that may have a perplexing problem especially to children. That is why the most common combinations which are administered in this way are the sulphate, salicylate, tannate and certain esters. Quinine tannate, an insoluble quinine salt has been known in medicine for a very long time. However, many experiments have revealed that quinine tannate was practically inert as a medicinal substance.
Status:
First marketed in 1921
Source:
Sodium Nitrite U.S.P.
Source URL:

Class (Stereo):
CHEMICAL (ACHIRAL)



Nitrite Ion is a symmetric anion with equal N–O bond lengths. Nitrite is important in biochemistry as a source of the potent vasodilator nitric oxide. Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as "Probably carcinogenic to humans" (Group 2A) by International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO) of the United Nations. Sodium nitrite is used for the curing of meat because it prevents bacterial growth and, as it is a reducing agent (opposite of oxidation agent), in a reaction with the meat's myoglobin, gives the product a desirable pink-red "fresh" color, such as with corned beef. This use of nitrite goes back to the Middle Ages, and in the US has been formally used since 1925. Because of the relatively high toxicity of nitrite (the lethal dose in humans is about 22 milligrams per kilogram of body weight), the maximum allowed nitrite concentration in meat products is 200 ppm. At these levels, some 80 to 90% of the nitrite in the average U.S. diet is not from cured meat products, but from natural nitrite production from vegetable nitrate intake. Under certain conditions – especially during cooking – nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens. However, the role of nitrites (and to some extent nitrates) in preventing botulism by preventing C. botulinum endospores from germinating have prevented the complete removal of nitrites from cured meat, and indeed by definition in the U.S., meat cannot be labeled as "cured" without nitrite addition. They are considered irreplaceable in the prevention of botulinum poisoning from consumption of cured dry sausages by preventing spore germination. Nitrite is a member of the drug class antidotes and is used to treat Cyanide Poisoning.
Status:
First marketed in 1921
Source:
calcium pentobarbital
Source URL:

Class (Stereo):
CHEMICAL (RACEMIC)



Pentobarbital belongs to the class of a short-acting barbiturate is used as sedatives, hypnotics, for the short-term treatment of insomnia, since they appear to lose their effectiveness for sleep induction and sleep maintenance after 2 weeks; preanesthetics and anticonvulsant, in anesthetic doses, in the emergency control of certain acute convulsive episodes, e.g., those associated with status epilepticus, cholera, eclampsia, meningitis, tetanus, and toxic reactions to strychnine or local anesthetics. Pentobarbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. All of these effects are associated with marked decreases in GABA-sensitive neuronal calcium conductance (gCa). The net result of barbiturate action is acute potentiation of inhibitory GABAergic tone. Barbiturates also act through potent (if less well characterized) and direct inhibition of excitatory AMPA-type glutamate receptors, resulting in a profound suppression of glutamatergic neurotransmission.
Barium sulfate, an insoluble in water substance, which was approved under the brand name E-Z-HD for use in double-contrast radiographic examinations of the esophagus, stomach and duodenum to visualize the gastrointestinal (GI) tract in patients 12 years and older. Due to its high atomic number, barium is opaque to x-rays and therefore acts as a positive contrast agent for radiographic studies.
Oxygen is a chemical element with atomic number 8. Diatomic oxygen constitutes 20.8% of the Earth's atmosphere. Diatomic oxygen is used by complex life forms such as animals, in cellular respiration. Medical oxygen is widely used in clinical practice to provide a basis for most modern anaesthetic techniques; to restore the tissue oxygen tension towards normal by improving oxygen availability in a wide range of conditions such as shock, severe haemorrhage, coronary occlusion, carbon monoxide poisoning, major trauma; to aid the resuscitation of the critically ill, when the circulation is impaired; to aid in neonatal resuscitation; to treat acute severe headache in adults diagnosed with cluster headache.
Status:
First marketed in 1827

Class (Stereo):
CHEMICAL (ABSOLUTE)


Conditions:

Morphine is one of the most important and widely used opioid for the treatment of chronic and acute pain: the very wide interindividual variability in the patients’ response to the drug may have genetic derivations. Sulphate salt of morphine sold under the many brand names, one of them, DURAMORPH, which is indicated for the management of pain severe enough to require use of an opioid analgesic by intravenous administration, and for which alternative treatments are not expected to be adequate. In addition for the epidural or intrathecal management of pain without attendant loss of motor, sensory, or sympathetic function. Morphine is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of morphine is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with morphine. The precise mechanism of the analgesic action is unknown. However, specific CNS opioid receptors for endogenous compounds with opioid-like activity have been identified throughout the brain and spinal cord and are thought to play a role in the analgesic effects of this drug. Morphine has a high potential for addiction and abuse. Common side effects include drowsiness, vomiting, and constipation. Caution is advised when used during pregnancy or breast-feeding, as morphine will affect the baby.
Status:
First marketed in 0652
Source:
alcohol
Source URL:

Class (Stereo):
CHEMICAL (ACHIRAL)



Alcohols exhibit rapid broad-spectrum antimicrobial activity against vegetative bacteria (including mycobacteria), viruses, and fungi but are not sporicidal. They are, however, known to inhibit sporulation and spore germination, but this effect is reversible. Because of the lack of sporicidal activity, alcohols are not recommended for sterilization but are widely used for both hard-surface disinfection and skin antisepsis. Lower concentrations may also be used as preservatives and to potentiate the activity of other biocides. Many alcohol products include low levels of other biocides (in particular chlorhexidine), which remain on the skin following evaporation of the alcohol, or excipients (including emollients), which decrease the evaporation time of the alcohol and can significantly increase product efficacy. Ethanol in combination with: chlorhexidine gluconate 1% was approved to use in surgical hand antiseptic. It significantly reduces the number of microorganisms on the hands and forearms prior to surgery or patient care. Ethanol is also used as a co-solvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol is metabolized by the hepatic enzyme alcohol dehydrogenase. Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes.
Status:
US Approved OTC
Source:
21 CFR 333.110(c) first aid antibiotic:ointment chlortetracycline hydrochloride
Source URL:
First approved in 1948
Source:
Aureomycin Calcium by Lederle
Source URL:

Class (Stereo):
CHEMICAL (ABSOLUTE)



Chlortetracycline (trade name Aureomycin, Lederle) is a tetracycline antibiotic, the first tetracycline to be identified. It was discovered in 1945 by Benjamin Minge Duggar working at Lederle Laboratories under the supervision of Yellapragada Subbarow. Duggar identified the antibiotic as the product of an actinomycete he cultured from a soil sample collected from Sanborn Field at the University of Missouri. The organism was named Streptomyces aureofaciens and the isolated drug, Aureomycin, because of their golden color. Chlortetracycline inhibits cell growth by inhibiting translation. It binds to the 16S part of the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. In veterinary medicine, chlortetracycline is commonly used to treat conjunctivitis in cats.
Status:
US Approved OTC
Source:
21 CFR 346.10(c) anorectal:local anesthetic dibucaine
Source URL:
First marketed in 1930
Source:
Dibucaine; Nupercaine by Society of Chemical Industry in Basle, Basle, Switzerland (Ciba Company, Inc., New York, distributor).
Source URL:

Class (Stereo):
CHEMICAL (ACHIRAL)


Conditions:

Dibucaine is used as a local anesthetic for surface anesthesia. It is one of the most potent and toxic of the long-acting local anesthetics and its parenteral use is restricted to spinal anesthesia. Dibucaine is used to temporarily relieve pain and itching due to: hemorrhoids or other anorectal disorders, sunburn, minor burns, minor cuts; scrapes, insect bites, minor skin irritation. This drug acts via blocking of nerve impulses by decreasing the neuronal membrane's permeability to sodium ions through sodium channel blocking. This reversibly stabilizes the membrane and inhibits depolarization, resulting in the failure of a propagated action potential and subsequent conduction blockade.