Sulfonamides

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      tanishalongshore
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      <br><br>Sulfonamides – agents, derivatives pair (π) – sulfanilic acid amide (para-aminobenzenesulfonic acid). Many of these substances have been used as antibacterial drugs since the mid-twentieth century. pair-Aminobenzenesulfamide – the simplest compound of the class – is also called white streptocide and is still used in medicine. Sulfanilamide prontosil (red streptocid), which is somewhat more complex in structure, was the first drug in this group and, in general, the first synthetic antibacterial drug in the world.<br><br>The antibacterial properties of prontosil were discovered in 1934 by G. Domagk. In 1935, at the Pasteur Institute (France) established that it is the sulfanilamide part of the prontosil molecule that has an antibacterial effect, and not the that gives it color. It was found that the „active principle» of red streptocide is sulfanilamide, which is formed during metabolism (streptocid, white streptocide). Red streptocid fell out of use, and a large number of its derivatives were synthesized on the basis of the sulfonamide molecule, some of which were widely used in medicine.<br>pharmachologic effect<br>Sulfonamides act bacteriostatically, that is, temporarily inhibit the ability of microorganisms to reproduce. Sulfonamides have chemotherapeutic activity in infections caused by gram-positive and gram-negative bacteria, some protozoa (causative agents of malaria, toxoplasmosis), chlamydia (with trachoma, paratrachoma).<br><br>Their action is mainly associated with a violation of the formation of growth factors necessary for their development by microorganisms – folic and dihydrofolic acids and other substances, the molecule of which includes para-aminobenzoic acid. The mechanism of action is associated with the structural similarity of the sulfanilamide fragment with pair-aminobenzoic acid (PABA) – a substrate of the enzyme dihydropteroate synthetase, which synthesizes dihydropteroic acid, which leads to a competitive inhibition of dihydropteroate synthetase. This, in turn, leads to a violation of the synthesis from dihydropteroic dihydrofolic and then tetrahydrofolic acid and, as a result, to a violation of the synthesis of nucleic acids in bacteria.<br><br>To obtain a therapeutic effect, they must be prescribed in doses sufficient to prevent the possibility of microorganisms using para-aminobenzoic acid contained in tissues. Taking sulfonamide drugs in insufficient doses or stopping treatment too early can lead to the emergence of resistant strains of pathogens that are not amenable to the further action of sulfonamides. Most clinically relevant bacteria are currently resistant to sulfonamides. It should be borne in mind that some drugs, the molecule of which includes the residue of para-aminobenzoic acid (for example, novocaine), can have a pronounced antisulfanilamide effect.<br>Pharmacological parameters<br>Available sulfa drugs differ in pharmacological parameters. Streptocide, norsulfazole, sulfazine, sulfadimezine, etazole, sulfapyridazine, sulfadimethoxine, etc. are relatively easily absorbed and rapidly accumulate in the blood and organs in bacteriostatic concentrations, penetrate the histohematological barriers (blood-brain, placental, etc.); they find application in the treatment of various infectious diseases. Other drugs, such as phthalazol, phtazin, sulgin, are difficult to absorb, are in the intestines for a relatively long time in high concentrations and are excreted mainly in the feces. Therefore, they are mainly used for infectious diseases of the gastrointestinal tract (dysentery, dysbiosis, gastric colitis). Urosulfan is excreted in significant quantities by the kidneys; it is used primarily for urinary tract infections.<br><br>By the time of excretion from the body, sulfonamides can be divided into 4 groups:<br>short-acting drugs (streptocid, norsulfazole, etazole, sulfadimezin, etc.);medium action (sulfazine, etc.);long-acting (sulfapyridazine, sulfamonomethoxin, sulfadimethoxine, etc.);ultra-long-acting (sulfalene, etc.).<br>Drugs that are slowly released from the body are called depot sulfonamides. Their slow excretion is largely due to the ability to be reabsorbed (reabsorbed) in the renal tubules after glomerular filtration. Absorption and the rate of excretion from the body largely determine the size of the dose and the frequency of drug intake. The maximum blood concentration of short-acting drugs decreases by 50%, usually in less than 8 hours, and 50% of them are excreted in the urine in less than 16 hours. 16 and 24-48 hours, excretion of 50% in the urine – after 16-24 and 24-56 hours, which makes it possible to prescribe these drugs less often and in smaller doses. Ultra-long-acting drugs are released even more slowly: their maximum concentration in the blood lasts up to 7 days.<br><br>Sulfanilamide preparations can be used in different combinations, if necessary. Poorly absorbed drugs can be administered concurrently with well-absorbed drugs. You can combine sulfonamides with antibiotics.<br>Indications<br>Infectious and inflammatory diseases caused by microorganisms sensitive to the drug: respiratory tract infections (acute and chronic bronchitis, bronchiectasis, croupous pneumonia, bronchopneumonia, pneumocystis pneumonia, pleural empyema, lung abscess), ENT infections (otitis media, sinusitis, laryngitis tonsillitis, pharyngitis, tonsillitis), scarlet fever, urinary tract infections (pyelonephritis, pyelitis, epididymitis, cystitis, urethritis, salpingitis, prostatitis, gonorrhea in men and women, chancre, lymphogranuloma venereal, inguinal cholema), gastrointestinal tract infections (dysentery, typhoid fever, salmonella, paratyphoid fever, cholecystitis, cholangitis, gastroenteritis caused by enterotoxic strains of E. coli), infections of the skin and soft tissues (acne, furunculosis, pyoderma, abscess, wound infections), osteomyelitis (acute and chronic), acute brucellosis , sepsis, peritonitis, meningitis, brain abscess, osteoarticular infections, South American blastomycosis, malaria, co hockey stick (as part of complex therapy).<br>Side effects<br>From the nervous system and sensory organs: headache, depression, apathy, dizziness, tremor, aseptic meningitis, peripheral neuritis.<br><br>From the side of the cardiovascular system and blood (hematopoiesis, hemostasis): thrombocytopenia, neutropenia, rarely – agranulocytosis, megaloblastic anemia.<br><br>From the respiratory system: bronchospasm, pulmonary infiltrates.<br><br>From the digestive tract: nausea, vomiting, diarrhea – dyspeptic and dyspeptic reactions, anorexia, gastritis, abdominal pain, glossitis, stomatitis, cholestasis, increased activity of hepatic transaminases, rarely – hepatitis, pseudomembranous colitis.<br><br>From the genitourinary system: polyuria, interstitial nephritis, impaired renal function, crystalluria, hematuria, increased urea, hypercreatininemia, toxic nephropathy, with oliguria and anuria.<br><br>From the musculoskeletal system: arthralgia, myalgia.<br><br>Allergic reactions: itching, photosensitivity, rash, fever, redness of the sclera, in some cases – Steven-Johnson polymorphic-bullous erythema, toxic epidermal necrolysis (Lyell’s syndrome), exfoliative dermatitis, allergic myocarditis, Quincke’s edema.<br>Overdose<br>Symptoms: nausea, vomiting, confusion, fainting, intestinal colic, dizziness, headache, drowsiness, depression, blurred vision, fever, hematuria, crystalluria; with prolonged overdose – thrombocytopenia, leukopenia, megaloblastic anemia, jaundice.<br><br>Treatment: withdrawal of the drug, gastric lavage (within 2 hours from the moment of taking the excessive dose), acidification of urine (to increase excretion of trimethoprim), drinking plenty of water, i / m – 5-15 mg / day. calcium folinate (eliminates the effect of trimethoprim on the bone marrow), forced diuresis, if necessary – hemodialysis.<br>Contraindications<br>Severe renal failure, blood diseases, deficiency of glucose-6-phosphate dehydrogenase, nephrosis, nephritis, acute porphyria, Graves’ disease, I and II trimesters of pregnancy, lactation, hypersensitivity to sulfonamides; it is strongly not recommended for children under 12 years of age.<br>special instructions<br>With long-term treatment, systematic monitoring of the blood picture, kidney and liver function is recommended. The drug should be administered with caution in case of impaired renal function. During the treatment period, it is necessary to increase the amount of consumed alkaline mineral liquid. If hypersensitivity reactions appear, the drug should be canceled.<br>List of some sulfonamidesAnalysis of sulfonamidesAuthenticity testAzo dye formation reaction<br>The reaction is based on the interaction of the drug with a solution of sodium nitrite in an acidic medium with the formation of diazonium chloride and its subsequent reaction with phenols to form a dye. For example, with β-naphthol, a cherry red color is formed.<br>Lignin assay<br>The reaction with the formation of Schiff bases is used for express analysis<br>Halogenation reactionsPyrolysis reactionColor reaction with heavy metal saltsReaction with sodium nitroprussideOxidation reactionsQuantitative analysisNitritometryNeutralization reactionBromatometryIodochlorometry

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