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Pharmacology of Antibiotics
The document discusses various classes of antibiotics including their mechanisms of action and clinical uses. It describes antibiotics that inhibit bacterial cell wall synthesis such as penicillins, cephalosporins, and carbapenems. It also discusses antibiotics that inhibit protein synthesis like macrolides, tetracyclines, and aminoglycosides. The document provides examples of narrow and broad-spectrum antibiotics and summarizes the clinical uses and important characteristics of selected antibiotics including penicillins, amoxicillin, ceftriaxone, and azithromycin. It also warns of potential adverse effects such as pseudomembranous colitis caused by antibiotics like clindamycin and lincomycin.
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Pharmacology of Antibiotics
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- 2. ANTIBIOTICS — arechemical compounds of biologic origin that exert selective damaging or subversive effect on microorganisms. There are antibiotics with Antibacterial, Antifungal and Antitumor actions . 22
- 3. I. Inhibitors ofcell wall synthesisI. Inhibitors of cell wall synthesis:: 1.1. β-Lactam antibioticsβ-Lactam antibiotics:: 2. Others2. Others:: PenicillinsPenicillins PolypeptidesPolypeptides CephalosporinsCephalosporins GlycopeptidesGlycopeptides CarbapenemsCarbapenems MonobactamsMonobactams II. Producing disturbance in cell wall permeability:II. Producing disturbance in cell wall permeability: Polypeptides (Polymyxins)Polypeptides (Polymyxins) III Protein synthesis inhibitorsIII Protein synthesis inhibitors:: MacrolidesMacrolides ChloramfenicolChloramfenicol TetracyclinesTetracyclines LincosamidesLincosamides AminoglicosidesAminoglicosides 33
- 5. 1. Narrow spectrum:1.Narrow spectrum: Gr(+) bacteria:Gr(+) bacteria: ●● Gr(-) bacteria:Gr(-) bacteria: BenzylpenicillinsBenzylpenicillins PolymyxinsPolymyxins OxacillinOxacillin ErythromycinErythromycin 2. Broad Spectrum:2. Broad Spectrum: TetracyclinesTetracyclines AminoglycosidesAminoglycosides Semi-synthetic Penicillins of Broad-spectrumSemi-synthetic Penicillins of Broad-spectrum CarbapenemsCarbapenems CephalosporinsCephalosporins Levomycetin (Levomycetin (ChloramphenicolChloramphenicol)) RifampicinRifampicin 55
- 6. PENICILLINSPENICILLINS I.I. Biosynthetical PenicillinsBiosyntheticalPenicillins:: Narrow SpectrumNarrow Spectrum Gr(+)Gr(+) A. For parenteral introductionA. For parenteral introduction:: Short actingShort acting (3-4 hs)(3-4 hs):: Benzylpenicillin-NatriumBenzylpenicillin-Natrium Benzylpenicillin-KaliumBenzylpenicillin-Kalium Long actingLong acting:: Benzylpenicillin-NovocainBenzylpenicillin-Novocain (12 hs)(12 hs) Bicillin-1Bicillin-1 (once a week)(once a week) Bicillin-5Bicillin-5 (once a month)(once a month) B. For enteral introduction:B. For enteral introduction: PhenoxymethylpenicillinPhenoxymethylpenicillin (4-6 hs)(4-6 hs) 66
- 7. II. Semisynthetic PenicillinsII.Semisynthetic Penicillins:: A. ForA. For parenteralparenteral andand enteralenteral introduction (introduction (acid-resistantacid-resistant):): 1.1. Penicillinase-resistant:Penicillinase-resistant: 2. Extended spectrum2. Extended spectrum:: OxacillinOxacillin •• AMINOPENICILLINS:AMINOPENICILLINS: CloxacillinCloxacillin AmoxicillinAmoxicillin FlucloxacillinFlucloxacillin AmpicillinAmpicillin MethicillinMethicillin BacampicillinBacampicillin B. ForB. For parenteralparenteral introductionintroduction:: BroadBroad spectrumspectrum includingincluding blue pus bacilliblue pus bacilli Pseudomonas aeruginosaPseudomonas aeruginosa:: •• Carboxy penicillinsCarboxy penicillins:: •• UreidopenicillinsUreidopenicillins:: Carbenicillin disodiumCarbenicillin disodium PiperacillinPiperacillin TicarcillinTicarcillin AzlocillinAzlocillin MezlocillinMezlocillin C. For enteral introductionC. For enteral introduction (acid-resistant):(acid-resistant): Carbenicillin-indanylCarbenicillin-indanyl Carbenicillin phenylCarbenicillin phenyl CarfecillinCarfecillin 77
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- 11. CLINICAL USE ofPENICILLINSCLINICAL USE of PENICILLINS Bacterial MeningitisBacterial Meningitis:: BenzylpenicillinBenzylpenicillin, high doses IV, high doses IV Bone and Joint InfectionsBone and Joint Infections (eg with(eg with Staphylococcus aureusStaphylococcus aureus)):: FlucloxacillinFlucloxacillin Skin and Soft Tissue InfectionsSkin and Soft Tissue Infections (eg with(eg with Streptococcus pyogenesStreptococcus pyogenes oror S. aureusS. aureus)):: Benzylpenicillin, FlucloxacillinBenzylpenicillin, Flucloxacillin animal bitesanimal bites:: CoamoxiclavCoamoxiclav PharyngitisPharyngitis ((S.pyogenesS.pyogenes) -) - PhenoximethylpenicillinPhenoximethylpenicillin BronchitisBronchitis (mixed infections common) and(mixed infections common) and PneumoniaPneumonia:: AmoxicillinAmoxicillin GonorrheaGonorrhea:: AmoxicillinAmoxicillin (plus(plus ProbenecidProbenecid)) SyphylisSyphylis:: Procain BenzylpenicillinProcain Benzylpenicillin EndocarditisEndocarditis (eg with(eg with Streptococcus viridansStreptococcus viridans oror Enterococcus faecalisEnterococcus faecalis)) 1111
- 12. Benzylpenicillin-natriumBenzylpenicillin-natrium (vial 500,000and 1,000,000 UA) -(vial 500,000 and 1,000,000 UA) - biosynthetical penicillin of narrow spectrum (biosynthetical penicillin of narrow spectrum (GramGram+).+). It is the drug of choice for infections caused by:It is the drug of choice for infections caused by: Streptococci, Meningococci, Enterococci,Streptococci, Meningococci, Enterococci, Penicillin-Susceptible Pneumococci,Penicillin-Susceptible Pneumococci, non-beta-lactamase-producing Staphylococci,non-beta-lactamase-producing Staphylococci, Treponema PallidumTreponema Pallidum and many otherand many other SpirochetesSpirochetes,, Bacillus Antracis, Clostridium SpeciesBacillus Antracis, Clostridium Species,, ActinomycesActinomyces and other Gr (+) rods,and other Gr (+) rods, Non-beta-lactamase-producingNon-beta-lactamase-producing Anaerobic organismsAnaerobic organisms Depending upon the organism, the site, and the severity ofDepending upon the organism, the site, and the severity of infection, effective doses range betweeninfection, effective doses range between 44 andand 24 mln24 mln UnitsUnits per day administered IV inper day administered IV in 4-64-6 divided doses.divided doses. 1212
- 13. Bicillin-5Bicillin-5 –– 1 partof1 part of benzylpenicillin-Novocainebenzylpenicillin-Novocaine (300,000 UA)(300,000 UA) 4 parts of4 parts of Biccilin-1Biccilin-1 (1,200,000 UA)(1,200,000 UA) The drug is used as suspension onlyThe drug is used as suspension only IM once 4 weeksIM once 4 weeks The drug provides high concentrations in the plasmaThe drug provides high concentrations in the plasma for long period of time (ad 4 weeks).for long period of time (ad 4 weeks). Infections byInfections by Streptococci, Pneumococci,Streptococci, Pneumococci, StaphylococciStaphylococci etc.etc. Bicillin-5 is especially useful for permanentBicillin-5 is especially useful for permanent (whole-year) prophylaxis of rheumatism relapses.(whole-year) prophylaxis of rheumatism relapses. 1313
- 14. AmoxicillinAmoxicillin (tab andcaps 250 and 500 mg)(tab and caps 250 and 500 mg) semisyntheticsemisynthetic bactericidal antibiotic ofbactericidal antibiotic of broad-spectrumbroad-spectrum actionaction (Gr+ and some Gr(-).(Gr+ and some Gr(-). The drug adheres to bacterialThe drug adheres to bacterial penicillin-bindingpenicillin-binding proteins, thusproteins, thus inhibiting bacterial cell synthesis.inhibiting bacterial cell synthesis. Systemic InfectionsSystemic Infections Urinary or Respiratory Tract InfectionsUrinary or Respiratory Tract Infections oral prophylaxis oforal prophylaxis of Bacterial EndocarditisBacterial Endocarditis.. Uncomplicated GonorrheaUncomplicated Gonorrhea (3 g PO as a single dose)(3 g PO as a single dose) Ulcer of the stomach and duodenumUlcer of the stomach and duodenum associating withassociating with Helicobacter pyloriHelicobacter pylori infection in combination with base agentsinfection in combination with base agents (inhibiting secretion and antacids).(inhibiting secretion and antacids). AdultsAdults:: usually 500 mg (in severe cases 1 g) PO q 8 hours.usually 500 mg (in severe cases 1 g) PO q 8 hours. Unwanted reactions:Unwanted reactions: Hypersensitivity Reactions, Seizures,Hypersensitivity Reactions, Seizures, Agranulocytosis, Hemolytic Anemia, Thrombocytopenia,Agranulocytosis, Hemolytic Anemia, Thrombocytopenia, Eosinophilia, Leukopenia, Interstitial Nephritis, Nephropathy,Eosinophilia, Leukopenia, Interstitial Nephritis, Nephropathy, EnterocolitisEnterocolitis 1414
- 15. CEPHALOSPORINSCEPHALOSPORINS I GenerationI Generation:: ParenteralcephalosporinsParenteral cephalosporins:: Cefazolin, CefalotinCefazolin, Cefalotin Enteral (PO) cephalosporinsEnteral (PO) cephalosporins:: CephalexinCephalexin II GenerationII Generation:: Parenteral cephalosporinsParenteral cephalosporins:: Cefuroxim, CefamandoleCefuroxim, Cefamandole Enteral cephalosporinsEnteral cephalosporins:: CefaclorCefaclor III GenerationIII Generation:: Parenteral cephalosporinsParenteral cephalosporins:: Ceftriaxone, Cefotaxime, CeftazidimeCeftriaxone, Cefotaxime, Ceftazidime Enteral cephalosporinsEnteral cephalosporins:: CefiximCefixim IV GenerationIV Generation:: Parenteral cephalosporinsParenteral cephalosporins:: Cefepime, CefpiromeCefepime, Cefpirome 1515
- 16. CeftriaxoneCeftriaxone (vial 0.5and 1.0) –(vial 0.5 and 1.0) – a 3d-generation cephalosporin, acts bactericidally bya 3d-generation cephalosporin, acts bactericidally by adhering to bacterial penicillin-binding proteins, inhibitingadhering to bacterial penicillin-binding proteins, inhibiting cell wall synthesis.cell wall synthesis. Ceftriaxon (Ceftriaxon (as a single 250 mg IM) andas a single 250 mg IM) and CefiximCefixim (as a single(as a single 400 mg PO) are 1st line drugs for treatment of400 mg PO) are 1st line drugs for treatment of GonorrheaGonorrhea IndicationsIndications:: Bacteremia, septicemia, respiratory, bone, joint,Bacteremia, septicemia, respiratory, bone, joint, urinary, gynecologic, intra-abdominal, and skin infectionsurinary, gynecologic, intra-abdominal, and skin infections from susceptible organismsfrom susceptible organisms;; Gonorrhea, gonococcal meningitis, Syphilis,Gonorrhea, gonococcal meningitis, Syphilis, Lyme disease, Endocarditis.Lyme disease, Endocarditis. 3d-generation cephalosporins3d-generation cephalosporins influence on hemostaticinfluence on hemostatic properties since they possessproperties since they possess coumarin-like actioncoumarin-like action, may, may induce bleeding disorders by decreasing level of plasmainduce bleeding disorders by decreasing level of plasma coagulation factors (II, VII, IX, X)coagulation factors (II, VII, IX, X);; inducinginducing hypoprothrombinemia. Administration ofhypoprothrombinemia. Administration of Vitamin KVitamin K, 10 mg, 10 mg twice weekly, can prevent this.twice weekly, can prevent this. 1616
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- 22. AzithromycinAzithromycin ((SumamedSumamed) tab.0.5, caps 0.25 g) tab. 0.5, caps 0.25 g Binds to theBinds to the 50S50S subunit of ribosomes,subunit of ribosomes, blocking Protein Synthesis.blocking Protein Synthesis. Active against respiratory infections due toActive against respiratory infections due to Haemophilus influenzaeHaemophilus influenzae andand Moraxella catarrhalisMoraxella catarrhalis.. Has excellent action againstHas excellent action against Toxoplasma gondiiToxoplasma gondii It is now preferred therapy forIt is now preferred therapy for urethritis caused byurethritis caused by Chlamidia TrachomatisChlamidia Trachomatis.. Penetrates into most tissues (except cerebrospinal fluid)Penetrates into most tissues (except cerebrospinal fluid) withwith TissueTissue >>>> Plasma ConcentrationPlasma Concentration by 10- 100-folds.by 10- 100-folds. Community-acquiredCommunity-acquired PneumoniaPneumonia can be treated withcan be treated with AzithromycinAzithromycin given asgiven as 500 mg500 mg loading dose, followed byloading dose, followed by aa 250 mg250 mg singly daily dose for the next 4 days.singly daily dose for the next 4 days. 2222
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- 27. Pseudomembranous ColitisPseudomembranous Colitis–– thethe most serious potentially fatal adverse effectmost serious potentially fatal adverse effect ofof ClindamycinClindamycin andand LincomycinLincomycin Caused by overgrowth ofCaused by overgrowth of ClostridiumClostridium difficiledifficile ((superinfection developmentsuperinfection development)) which elaborateswhich elaborates necrotizing toxinsnecrotizing toxins .. The patient develops profuse, watery diarrhea,The patient develops profuse, watery diarrhea, fever, abdominal pain, leukocytosis.fever, abdominal pain, leukocytosis. C. difficileC. difficile infection is confirmed.infection is confirmed. Treatment: Oral administration ofTreatment: Oral administration of MetronidazoleMetronidazole oror VancomycinVancomycin is effectiveis effective in controlling this serious problem.in controlling this serious problem. 2727
- 28. Thank You forListening!Thank You for Listening! 2828