Tachyphylaxis
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Tachyphylaxis
Tachyphylaxis (Greek ταχύς, ''tachys'', "rapid", and φύλαξις, ''phylaxis'', "protection") is a medical term describing an acute, sudden decrease in response to a drug after its administration; i.e. a rapid and short-term onset of drug tolerance. It can occur after an initial dose or after a series of small doses. Increasing the dose of the drug may be able to restore the original response. Characteristics Tachyphylaxis is characterized by the rate sensitivity: the response of the system depends on the rate with which a stimulus is presented. To be specific, a high-intensity prolonged stimulus or often-repeated stimulus may bring about a diminished response also known as desensitization. Molecular interaction In biological sciences, molecular interactions are the physical bases of the operation of the system. The control of the operation, in general, involves interaction of a stimulus molecule with a receptor/enzyme subsystem by, typically, binding to the macromolecule A a ...
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Nitrovasodilator
A nitrovasodilator is a pharmaceutical agent that causes vasodilation (widening of blood vessels) by donation of nitric oxide (NO), and is mostly used for the treatment and prevention of angina pectoris. This group of drugs includes nitrates (esters of nitric acid), which are reduced to NO in the body, as well as some other substances. Examples Here is a list of examples of the nitrate type (in alphabetical order): #Diethylene glycol dinitrate #Glyceryl trinitrate (nitroglycerin) #Isosorbide mononitrate and dinitrate # Itramin tosilate #Nicorandil (which additionally acts as a potassium channel opener) # Pentaerithrityl tetranitrate # Propatylnitrate # Sinitrodil #Tenitramine #Trolnitrate Nitrovasodilators which aren't nitrates include molsidomine and its active metabolite linsidomine, as well as sodium nitroprusside. These substances do not need to be reduced to donate NO. Medical uses The nitrates are used for the treatment and prevention of angina and acute myocard ...
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Drug Tolerance
Drug tolerance or drug insensitivity is a pharmacological concept describing subjects' reduced reaction to a drug following its repeated use. Increasing its dosage may re-amplify the drug's effects; however, this may accelerate tolerance, further reducing the drug's effects. Drug tolerance is indicative of drug use but is not necessarily associated with drug dependence or addiction. The process of tolerance development is reversible (e.g., through a drug holiday) and can involve both physiological factors and psychological factors. One may also develop drug tolerance to side effects, in which case tolerance is a desirable characteristic. A medical intervention that has an objective to increase tolerance (e.g., allergen immunotherapy, in which one is exposed to larger and larger amounts of allergen to decrease one's allergic reactions) is called drug desensitization. The opposite concept to drug tolerance is drug reverse tolerance (or drug sensitization), in which case the sub ...
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Physiological Tolerance
Drug tolerance or drug insensitivity is a Pharmacology, pharmacological concept describing subjects' reduced reaction to a drug following its repeated use. Increasing its dosage may re-amplify the drug's effects; however, this may accelerate tolerance, further reducing the drug's effects. Drug tolerance is indicative of drug use but is not necessarily associated with drug dependence or addiction. The process of tolerance development is reversible (e.g., through a drug holiday) and can involve both physiological factors and psychological factors. One may also develop drug tolerance to side effects, in which case tolerance is a desirable characteristic. A medical intervention that has an objective to increase tolerance (e.g., allergen immunotherapy, in which one is exposed to larger and larger amounts of allergen to decrease one's allergic reactions) is called Desensitization (medicine), drug desensitization. The opposite concept to drug tolerance is Reverse tolerance, drug reverse ...
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Nitroglycerine (pharmacology)
Nitroglycerin, also known as glyceryl trinitrate (GTN), is a medication used for heart failure, high blood pressure, anal fissures, painful periods, and to treat and prevent chest pain caused by decreased blood flow to the heart (angina) or due to the recreational use of cocaine. This includes chest pain from a heart attack. It is taken by mouth, under the tongue, applied to the skin, or by injection into a vein. Common side effects include headache and low blood pressure. The low blood pressure can be severe. It is unclear if use in pregnancy is safe for the baby. It should not be used together with medications within the PDE5 inhibitor family such as sildenafil due to the risk of low blood pressure. Nitroglycerin is in the nitrate family of medications. While it is not entirely clear how it works, it is believed to function by dilating blood vessels. Nitroglycerin was written about as early as 1846 and came into medical use in 1878. It is on the World Health Organizat ...
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Ranitidine
Ranitidine, sold under the brand name Zantac among others, is a medication used to decrease stomach acid production. It is commonly used in treatment of peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. It can be given by mouth, injection into a muscle, or injection into a vein. In September 2019, the probable carcinogen ''N''-nitrosodimethylamine (NDMA) was discovered in ranitidine products from a number of manufacturers, resulting in recalls. In April 2020, ranitidine was withdrawn from the United States market and suspended in the European Union and Australia due to these concerns. Common side effects include headaches and pain or burning if given by injection. Serious side effects may include liver problems, a slow heart rate, pneumonia, and the potential of masking stomach cancer. It is also linked to an increased risk of ''Clostridium difficile'' colitis. Ranitidine is an H2 histamine receptor antagonist that works by blockin ...
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Greek Language
Greek ( el, label=Modern Greek, Ελληνικά, Elliniká, ; grc, Ἑλληνική, Hellēnikḗ) is an independent branch of the Indo-European family of languages, native to Greece, Cyprus, southern Italy (Calabria and Salento), southern Albania, and other regions of the Balkans, the Black Sea coast, Asia Minor, and the Eastern Mediterranean. It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet, which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems. The Greek language holds a very important place in the history of the Western world. Beginning with the epics of Homer, ancient Greek literature includes many works of lasting impo ...
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Congestive Heart Failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, and leg swelling. The shortness of breath may occur with exertion or while lying down, and may wake people up during the night. Chest pain, including angina, is not usually caused by heart failure, but may occur if the heart failure was caused by a heart attack. The severity of the heart failure is measured by the severity of symptoms during exercise. Other conditions that may have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by altering ...
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Physical Dependence
Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms. Physical dependence can develop from low-dose therapeutic use of certain medications such as benzodiazepines, opioids, antiepileptics and antidepressants, as well as the recreational misuse of drugs such as alcohol, opioids and benzodiazepines. The higher the dose used, the greater the duration of use, and the earlier age use began are predictive of worsened physical dependence and thus more severe withdrawal syndromes. Acute withdrawal syndromes can last days, weeks or months. Protracted withdrawal syndrome, also known as post-acute-withdrawal syndrome or "PAWS", is a low-grade continuation of some of the symptoms of acute withdrawal, typically in a remitting-relapsing pattern, often resulting in relapse and prolonged disability of a degree to preclude the possibility of lawful employment. Protracted withdra ...
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Mithridatism
Mithridatism is the practice of protecting oneself against a poison by gradually self-administering non-lethal amounts. The word is derived from Mithridates VI, the King of Pontus, who so feared being poisoned that he regularly ingested small doses, aiming to develop immunity. Background Mithridates VI's father, Mithridates V, was assassinated by poisoning by a conspiracy among his attendants. After this, Mithridates VI's mother held regency over Pontus (a Hellenistic kingdom, 281 BC–62 AD) until a male heir came of age. Mithridates was in competition with his brother for the throne and his mother began to favor his brother. Supposedly, during his youth, he began to suspect plots against him at his own mother's orders and was aware of her possible connection with his father's death. He then began to notice pains in his stomach during his meals and suspected his mother had ordered small amounts of poison to be added to his food to slowly kill him off. With other assassination at ...
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Habituation
Habituation is a form of non-associative learning in which an innate (non-reinforced) response to a stimulus decreases after repeated or prolonged presentations of that stimulus. Responses that habituate include those that involve the intact organism (e.g., full-body startle response) or those that involve only components of the organism (e.g., habituation of neurotransmitter release from ''in vitro'' Aplysia sensory neurons). The broad ubiquity of habituation across all biologic phyla has resulted in it being called "the simplest, most universal form of learning...as fundamental a characteristic of life as DNA." Functionally-speaking, by diminishing the response to an inconsequential stimulus, habituation is thought to free-up cognitive resources to other stimuli that are associated with biologically important events (i.e., punishment/reward). For example, organisms may habituate to repeated sudden loud noises when they learn these have no consequences. A progressive decline of a ...
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Desensitization (medicine)
In medicine, desensitization is a method to reduce or eliminate an organism's negative reaction to a substance or stimulus. In pharmacology, ''drug desensitization'' refers to two related concepts. First, desensitization may be equivalent to drug tolerance and refers to subjects' reactions (positive or negative) to a drug reducing following its repeated use. This is a macroscopic, organism-level effect and differs from the second meaning of desensitization, which refers to a biochemical effect where individual receptors become less responsive after repeated application of an agonist. This may be mediated by phosphorylation, for instance by beta adrenoceptor kinase at the beta adrenoceptor. Application to allergies For example, if a person with diabetes mellitus has a bad allergic reaction to taking a full dose of beef insulin, the person is given a very small amount of the insulin at first, so small that the person has no adverse reaction or very limited symptoms as a result. Ov ...
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Fluticasone
Fluticasone is a manufactured glucocorticoid used to treat nasal symptoms. Both the esters, fluticasone propionate (a brand name for which is Flovent) and fluticasone furoate, are also used as topical anti-inflammatories and inhaled corticosteroids, and are used much more commonly in comparison. It is on the World Health Organization's List of Essential Medicines. In 2020, it was the 23rd most commonly prescribed medication in the United States, with more than 24million prescriptions, although it is also sold over the counter. See also * Fluticasone furoate ** Fluticasone furoate/vilanterol * Fluticasone propionate ** Fluticasone/salmeterol Fluticasone/salmeterol, sold under the brand name Advair among others, is a fixed-dose combination medication containing fluticasone propionate and salmeterol. It is used in the management of asthma and chronic obstructive pulmonary disease (C ... References External links * Antiasthmatic drugs Diketones Diols Dr ...
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