Antibiotics have many mechanisms such. For example, the inhibition of cell wall synthesis; an increase in cell membrane permeability and disruption of protein synthesis, nucleic acid metabolism and other metabolic processes (eg. as folic acid synthesis).
Antibacterial agents are made from bacteria or fungi or by de novo synthesis. Technically, “antibiotic” refers only to antibiotics, which are obtained from bacteria or fungi, but is often used (also in the MSD Manual) as a synonym for “antibacterial agent”. Antibiotics have many mechanisms such. For example, the inhibition of cell wall synthesis; an increase in cell membrane permeability and disruption of protein synthesis, nucleic acid metabolism and other metabolic processes (eg. as folic acid synthesis). Antibiotics sometimes interact with other drugs and increase or decrease the serum levels (see Table: Common effects of antibiotics on other drugs). The clinically most important interactions are used for substances with a low therapeutic index in front of (i. E., The toxic dose is close to the therapeutic dose). Other active ingredients can increase or decrease the doses of antibiotics. Many antibiotics are chemically related and are therefore divided into classes. Although substances have structural and functional similarities within a class, they often have different pharmacological properties and activity spectra. Common effects of antibiotics on other medicinal drug toxicity is amplified by No interaction with digoxin All macrolides (azithromycin, clarithromycin, erythromycin) doxycycline tetracycline trimethoprim aminoglycosides cephalosporins, clindamycin fluoroquinolones ketoconazole linezolid metronidazole penicillins quinupristin / dalfopristin sulfonamides vancomycin phenytoin chloramphenicol, ciprofloxacin isoniazid Some macrolides (erythromycin, Cl arithromycin, telithromycin) Rifampicin (reduces the phenytoin) sulfonamides azithromycin aminoglycosides, cephalosporins, clindamycin, doxycycline fluoroquinolones except ciprofloxacin linezolid, metronidazole, penicillins, quinupristin / dalfopristin, tetracycline trimethoprim vancomycin theophylline, ciprofloxacin, clarithromycin, erythromycin rifampicin (reduces the theophylline) aminoglycosides Azithromycin Cephalosporins Clindamycin Doxycycline Linezolid Metronidazole penicillins quinupristin / dalfopristin sulfonamides tetracyclines trimethoprim vancomycin warfarin * cefoperazone Cefotetan chloramphenicol clarithromycin doxycycline erythromycin Certain fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, ofloxacin) metronidazole rifampicin (PT-reduction) sulfonamides aminoglycosides azithromycin cephalosporins (some) Clindamycin Doxycycline Linezolid penicillins quinupristin / dalfopristin tetracycline trimethoprim vancomycin. These drugs interfere with vitamin K-dependent coagulation factors and may also increase the risk of bleeding when platelet aggregation inhibitors and thrombolytics. Selection and use of antibiotics Antibiotics should only be used when clinical or medical laboratory evidence of bacterial infection are present. The use in virus-induced diseases or non-specific fever is inadequate in most cases; puts patients without benefit of the undesirable effects of the drug, and promotes the development of bacterial resistance. Certain bacterial infections (eg. As abscesses, foreign body infections) require surgical intervention and do not respond to antibiotics on their own. Spectrum of cultures and antibiotic sensitivity tests for the selection of a substance are required in severe infections. Nevertheless, the therapy often has to use before the results of the exciting cultural present, allowing selection for the allegedly present pathogen requires (empirical antibiotic selection). Regardless of whether the antibiotic due selected empirically culture results or was, the selected material should have the narrowest spectrum of activity that is suitable for the control of infection. For the empirical treatment of severe infections where each of a wide range of pathogens may be involved (eg. As fever in neutropenic patients) may be based, or different to a mixture pathogens (eg. As polymicrobial Anaerobierinfektionen), is a broad spectrum desirable. The most likely pathogens and their sensitivity to antibiotics vary depending on the geographical location (within cities or even within a hospital) and may change from month to month. In severe infections combinations of antibiotics are often necessary, as several types of bacteria may be present or because combinations act synergistically against a single species of bacteria. Synergism is generally defined as a more rapid or more comprehensive anti-bacterial effect which is achieved by a combination of antibiotics. A typical example is a cell-wall active antibiotic (eg. As a ?-lactam, vancomycin) together with a Aminoglykosid.Wirksamkeit The antibacterial activity in vivo includes various factors such as pharmacokinetic parameters (eg. as absorption, distribution, concentration in fluids and tissues, protein binding, of metabolism or excretion rate) pharmacodynamic parameters (ie, the time course of antibacterial activity influenced by the drug levels in the blood and at the site of infection) interactions with other drugs or the presence of inhibitory substances host defenses bactericides substances kill off bacteria. Bacteriostatic drugs slow or stop the growth in vitro. These definitions are not absolute; also bacteriostatic drugs can kill some bacteria susceptible species, while bactericidal substances can only restrict the growth of some susceptible bacterial species. Bactericidal antibiotics in patients can be preferred who have infections that affect host defenses locally (eg. As meningitis, endocarditis), or in patients who are immunocompromised (eg. As neutropenia). Päzisere quantitative methods to identify the minimum in vitro concentration of an antibiotic from the growth inhibiting (minimum inhibitory concentration, MIC) or may cause the death (minimal bactericidal concentration, MBC). An antibiotic with a bactericidal activity is important if the host defense is restricted locally to the site of infection (z. B. meningitis or endocarditis) or systemically (eg. As in patients who are immunocompromised neutroprenisch or otherwise). The predominant determinant of bacteriological response to antibiotics is either time that the blood levels of the antibiotic, the MIC exceeds (time dependence) blood peak levels with respect to the MIC (concentration dependence) ?-lactam antibiotics and vancomycin have a time-dependent bactericidal activity on. An increase in their concentration over the MIC does not increase their bactericidal activity, and it is in vivo killing assets generally slow. In addition, ?-lactams are generally only effective when the serum-free present active ingredients (that is, not to serum protein-bound substances), the MIC pass over ? 50% of the time because they inhibit bacterial growth only slightly or not at all if the concentration under the MIC falls (postantibiotischer effect PAE). The long serum half-life of ceftriaxone leads to the result that the free serum levels exceed the MIC very sensitive pathogens over the entire 24-hour dosing interval. For ?-lactams, the serum half-lives ? 2 h have frequent doses or continuous infusion is required. Vancomycin a trough level of at least 15 to 20 ug / ml should be maintained. Aminoglycosides, fluoroquinolones and daptomycin have a concentration-dependent bactericidal activity. An increase in their concentration of mirrors slightly above the MIC to a level that is well above the MIC, increased its bactericidal activity and reduced the bacterial load. Furthermore have aminoglycosides and fluoroquinolones, if their concentration exceeds the MIC even briefly, one postantibiotic effect on the resident flora on; the duration of this postantibiotic effect is also concentration dependent. When the PAE lasts long, the drug levels can be a long time below the MIC, without leading to a loss of effectiveness, which allows less frequent application. Consequently, aminoglycosides and fluoroquinolones are usually most effective when they are given as intermittent bolus and free achieve peak serum levels which are ? 10-fold excess of the MIC of the bacteria; usually the Tiefstspiegel are not wichtig.Applikation Many antibiotics oral administration almost as quickly leads to therapeutic blood levels as i.v. application. I.v. Application is preferred in the following cases: Oral antibiotics are not tolerated (eg due to vomiting.). Oral antibiotics can not be recorded (for. Example because of malabsorption after bowel surgery). Intestinal motility is impaired (for. Example, due to opiates). An oral preparation is not available (eg. As for aminoglycosides). The patients are seriously ill and the blood flow to the gastrointestinal tract may be affected or the short-term delay of the onset of action after oral administration could be harmful. Special populations The dose and frequency of antibiotics must be adapted to the following people if necessary: ??Children Elderly patients with renal impairment (see Table: Usual doses of commonly prescribed antibiotics). Patients with hepatic impairment (applies most commonly used for cefoperazone, chloramphenicol, metronidazole, rifabutin and rifampin) pregnancy and lactation affect the choice of antibiotic. Penicillins, cephalosporins and erythromycin are among the safest antibiotics during pregnancy; Tetracyclines are contraindicated. Most antibiotics reach a sufficient concentration in breast milk in order to influence a brustgestilltes baby, which sometimes is a contraindication to its use in nursing mothers. Usual doses of commonly prescribed antibiotic drug dose for adults children (age> 1 month) dose dose Niereninsuffizienza (creatinine clearance <10 ml / min) Oral Parenteral Severe infections Oral Parenteral aminoglycosides amikacin N / A 15 mg / kg i.v. once / day or 7.5 mg / kg every 12 h 15 mg / kg i.v. once / day or 7.5 mg / kg iv every 12 h N / A 5-7.5 mg / kg i.v. every 12 h 1.5-2.5 mg / kg i.v. every 24-48 h gentamicin N / A 5-7 mg / kg i.v. once / day or 1.7 mg / kg iv every 8 h 5-7 mg / kg i.v. once / day A N / 1-2.5 mg / kg i.v. every 8 h from 0.34 to 0.51 mg / kg i.v. every 24-48 hours for a synergistic effect with a cell wall-active antibiotic in Enterokokkenendokarditis caused by a sensitive strain to gentamicin. N / A 1 mg / kg i.v.alle 8 h N / A N / A 1 mg / kg i.v. every 8 h In infectious diseases advice in dosage is required. The dosage must be adjusted to achieve maximum serum concentration of 3-4 ug / mL and minimum concentration of <1 ug / ml. For streptococcal or Staphylococcus aureus endocarditis - 1 mg / kg i.v. every 8 h or 3 mg / kg i.v. once / day A N / A N / 1 mg / kg i.v. every 8 h or 3 mg / kg i.v. once / day N / A neomycin for preoperative bowel cleaning (with erythromycin and mechanical cleaning) 1 g for 3 doses (eg. as at 1, 2 and 11 hours on the day before surgery) N / A N / A 15 mg / kg every 4 h for 2 days or 25 mg / kg after 1, 2 and 11 hours on the day prior to surgery N / A N / A for hepatic coma 1-3 g 4 times a day N / AN / A 0.6 to 1.75 g / m2 every 6 hours or 0.4-1.2 g / m2 every 4 h N / A N / A streptomycin For TB N / A 15 mg / kg i.m. every 24 h (maximum 1.0 g / day) initially, then 1.0 g of 2- to 3 times / week N / A N / A 20-40 mg / kg i.m. once / day to 7.5 mg / kg i.m. all of 72-96 h (maximum 1 g) for a synergistic effect with a cell wall-active antibiotic in Enterokokkenendokarditis N / A 7.5 mg / kg i.m. every 12 h N / A N / A N / A N / A tobramycin N / A 5-7 mg / kg i.v. 1 time / day or 1.7 mg / kg i.v. every 8 h 5-7 mg / kg i.v. once / day or 1.7 mg / kg iv every 8 h N / A 1-2.5 mg / kg i.v. every 8 h from 0.34 to 0.51 mg / kg i.v. every 24-48 h ?-lactams: cephalosporins (first generation) Cefadroxil 0.5-1 g every 12 h N / A N / A 15 mg / kg every 12 h N / A 0.5 g p.o. every 36 h cefazolin N / A 1-2 g i.v. every 8 h 2 g i.v. every 8 h N / A 16.6 to 33.3 mg / kg i.v. every 8 h 1-2 g i.v. every 24-48 h Cephalexin 0.25-0.5 g every 6 h N / A N / A 6.25 to 12.5 mg / kg every 6 hours or 8.0-16 mg / kg every 8 h N / A 0.25-0.5 g po every 24-48 h ?-lactams: cephalosporins (second generation) Cefaclorb 0.25-0.5 g every 8 h N / A N / A 10-20 mg / kg every 12 h or 6.6 to 13.3 mg / kg every 8 h N / A 0.5 g po every 12 h cefotetan N / A 1-3 g i.v. every 12 h 2-3 g iv every 12 h N / A 20-40 mg / kg i.v. every 12 hours 1-3 g i.v. every 48 h cefoxitin N / A 1 g i.v. every 8 h to 2 g i.v. every 4 h 2 g i.v. every 4 h or 3 g i.v. every 6 h N / A 27-33 mg / kg i.v. every 8 h or in severe infections, 25-40 mg / kg every 6 h 0.5-1.0 g i.v. every 24-48 h cefprozil 0.25 g every 12 h or 0.5 g every 12-24 h N / A N / A 15 mg / kg every 12 h for otitis media N / A 0.25 g p.o. every 12-24 h Cefuroxime 0.125-0.5 g every 12 h 0.75-1.5 g i.v. every 6-8 h 1.5 g iv every 6 hours from 10 to 15 mg / kg every 12 hours suspension For older children: 125-250 mg tablets every 12 hours 25-50 mg / kg i.v. every 8 h 0.25-0.5 g p.o. every 24 h or 0.75 g i.v. every 24 h for meningitis - - 3 g iv every 8 h - 50-60 mg / kg i.v. every 6 h - ?-lactams: cephalosporins (third generation) Cefotaxime N / A 1 g every 12 hours up to 2 g i.v. every 4 h 2 g i.v. every 4 h N / A 8.3 to 33.3 mg / kg i.v. every 4 h or 16.6 to 66.6 mg / kg every 6 h 1-2 g i.v. every 24 h Cefpodoximec 0.1-0.4 g every 12 h N / A N / A 5 mg / kg every 12 hours N / A 0.1-0.4 g p.o. every 24 h Ceftazidime N / A 1 g i.v. every 12 h to 2 g every 8 h 2 g i.v. every 8 h N / A 25-50 mg / kg i.v. every 8 h 0.5 g i.v. every 24-48 h Ceftibutenb 0.4 g every 24 h N / A N / A 9 mg / kg once / day N / A 0.1 g p.o. every 24 h Ceftriaxone N / A 1-2 g i.v. every 24 h 2 g i.v. every 24 h N / A 50-75 mg / kg i.v. every 24 h or 25 to 37.5 mg / kg every 12 h Same as adult dose for meningitis N / A 2 g i.v. every 12 h 2 g i.v. every 12 h N / A 50 mg / kg i.v. every 12 h or 100 mg / kg every 24 h (not 4 g / day exceed) may receive an initial dose of 100 mg / kg i.v. (Not exceed 4 g) at the start of treatment 2 g i.v. every 12 hours ?-lactams: cephalosporin (4th generation) Cefepime N / A 1-2 g i.v. every 8-12 h 2 g i.v. every 8 h N / A 50 mg / kg i.v. every 8-12 h 0.25-1 g iv every 24 hours ?-lactams: cephalosporin (5th generation) Ceftarolin N / A 0.6 g i.v. every 12 h 0.6 g i.v. every 12 h N / A N / A 0.2 g i.v. every 12 hours ?-lactams: penicillins amoxicillin 0.25-0.5 g every 8 h or 0.875 g every 12 h N / AN / A 12.5-25 mg / kg every 12 h or 7-13 mg / kg every 8 h N / A 0.25-0.5 g po every 24 h endocarditis prophylaxis 2 g dose for 1 N / A N / A 50 mg / kg 1 h prior to engagement N / A 2 g p.o. for 1 dose of amoxicillin / clavulanic acid 0.25-0.5 g every 8 h or 0.875 g every 12 h N / A N / A If of> 40 kg: adult dose N / A 0.25-0.5 g p.o. every 24 h amoxicillin / clavulanic acid, ES-600 N / AN / AN / A 45 mg / kg every 12 h N / AN / A amoxicillin / clavulanic acid, sustained drug establishment 2 g every 12 h N / AN / AN / AN / AN / A ampicillin N / A 0.5-2.0 g iv every 4-6 h 2 g i.v. every 4 h N / A 25-50 mg / kg i.v. every 6 h 0.5-2.0 g i.v. For every 12-24 h meningitis N / A 2 g i.v. every 4 h 2 g i.v. every 4 h N / A 50-100 mg / kg i.v. every 6 h 2 g i.v. every 12 h ampicillin / sulbactam (3 g = g 2 + Ampicillin 1 g sulbactam) N / A 1.5-3.0 g i.v. every 6 h 3 g i.v. every 6 h N / A 25-50 mg / kg i.v. every 6 h 1.5-3.0 g i.v. every 24 h Dicloxacillinb 0.125-0.5 g every 6 h N / A N / A 3.125 to 6.25 mg / kg every 6 h N / A 0.125-0.5 g p.o. every 6 h nafcillin Rarely used 1-2 g i.v. every 4 h 2 g i.v. every 4 h N / A 12.5-25 mg / kg i.v. every 6 hours or from 8.3 to 33.3 mg / kg every 4 h 1-2 g i.v. every 4 h oxacillin Rarely used 1-2 g i.v. every 4 h 2 g i.v. every 4 h N / A 12.5-25 mg / kg i.v. every 6 hours or from 8.3 to 33.3 mg / kg i.v. every 4 h 1-2 g i.v. every 4 h penicillin Gb 0.25-0.5 g every 6-12 h (penicillin V) 1-4 million units i.v. every 4-6 h 4 million units iv every 4 h Penicillin VK 6.25 to 12.5 mg / kg every 8 h 6250-100000 units / kg i.v. every 6 hours or 4166.6 to 66,666 units / kg i.v. every 4 h 0.5-2 million units iv q 46 h (maximale Tagesdosis: 6 Mio. Einheiten/Tag) Penicillin G Benzathin (Bicillin © LA) Für Streptokokkenpharyngitis N/A 1,2 Mio. Einheiten i.m. für 1 Dosis N/A N/A 25.00050.000 Einheiten/kg i.m. als Einzeldosis oder Wenn < 27 kg: 300.000600.000 Einheiten als Einzeldosis oder Wenn ? 27 kg: 0,9 Mio. Einheiten als Einzeldosis 1,2 Mio. Einheiten i.m. für 1 Dosis Prophylaxe bei rheumatischem Fieber N/A 1,2 Mio. Einheiten i.m. alle 34 Wochen N/A N/A 25.00050.000 Einheiten/kg i.m. alle 34 Wochen 1,2 Mio. Einheiten i.m. alle 34 Woc