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ANTIBIOTICS IN URINARY TRACT INFECTION

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					ANTIBIOTICS IN
URINARY TRACT INFECTION
  OBJECTIVES
• classify the antibiotics that are
  commonly used in the treatment of UTI
  and name the commonly used drugs in
  each class.
• explain the mechanism of action and its
  antibacterial activity of each class of
  antibiotics.
• describe the pharmacokinetics of each
  class of antibiotics.
• list the adverse effects of the antibiotics
  and its contraindications.
  ANTIBIOTICS – commonly
  used in UTI
• Trimethoprim
• Sulfonamides
• Penicillines
• Cephalosporins
• Quinolones
• Fluoroquinolones
• Nitrofurantoin
• Methenamine
   ANTIBIOTICS – commonly used
   in UTI
• Trimethoprim
• Sulfonamides - sulfisoxazole, sulfamethoxazole
  Co-trimoxazole (Trimethoprim-sulfamethoxazole)
• Penicillines - amoxicillin, ampicillin, amoxicillin-
  clavulanate (augmentin)
• Cephalosporins - 1st gen.(cephalexin), 2nd gen.
  (cefaclor, cefuroxime), 3rd gen. (cefixime,
  cefotaxime)
• Quinolones – nalidixic acid
• Fluoroquinolones - ciprofloxacin, norfloxacin,
  ofloxacin, levofloxacin
• Nitrofurantoin
• Methenamine
  ANTIBIOTICS – commonly used
  in UTI
Co-trimoxazole
 (Trimethoprim-sulfamethoxazole)
• Combine – similar half-life
• Produce sequential blocking of folic acid
  synthesis → synergism effect
• both bacteriostatic combined → bactericidal
• Broader spectrum of organism
• Resistance less frequent
       Mechanism of action
Antibiotic grp   Mechanism of action
Trimethoprim     -Act on 2nd step folic acid
                 synthesis pathway (antimetabolites)
                 -Inhibit dihydrofolate reductase
                 enzyme
                 -Prevent reduction of dihydrofolate to
                 tetrahydrofolate
Sulfonamides     -Inhibit folic acid synthesis
                 -Competitive inhibitor to PABA for
                 dihydropteroate synthase
                 -Inhibits incorporation of PABA into
                 folic acid
 MOA
                            PABA             Sulfonamides

Dihydropteroate synthase

                     Dihydrofolic Acid

  Dihydrofolate reductase                   Trimethoprim

                     Tetrahydrofolic Acid


                   Purines & Pyrimidines



                      DNA Synthesis
       Mechanism of action
Antibiotic       Mechanism of action
group
Penicillines     -Bind on a specific receptor
                 penicilline binding protein
                 -Inhibits transpeptidase
                 enzymes, interferes with the
                 cross linkages of peptidoglycan
                 chains
                 -Stimulates cytolytic enzymes,
                 autolysins on the cell wall & lysis
                 of the bacteria
Cephalosporins Similar to penicillin
       Mechanism of action
Antibiotic group    Mechanism of action
Quinolones &     -Inhibit replication of bacterial
fluoroquinolones DNA by interfering with the
                 DNA gyrase


Nitrofurantoin      -Damage bacterial DNA


Methenamine         -Form formaldehyde in acidic
                    urine
                    -Damage bacterial DNA
         Antibacterial activity
Antibiotic grp   Antibacterial activity
Trimethoprim     -bacteriostatic
                 -broad spectrum (enterobacteria, chlamydia,
                 pneumocystis, nocardia)
                 -20-50X > potent than sulfonamide
Sulfonamides     -bacteriostatic
                 -broad spectrum
Co-trimoxazole   -bactericidal
                 -broader spectrum (Gm+ve, Gm-ve, protozoa)
Penicillines     - bactericidal
                 -broad spectrum
Cephalosporins -bactericidal
               1st gen-high activity vs Gm+ve, weak vs. Gr-ve
               (PEcK)
               2nd gen-> activity vs. Gr-ve & more potent (HENPEcK
               3rd gen- >> activity vs. Gm-ve, < activity vs. Gm+ve
         Antibacterial activity
Antibiotic group   Antibacterial activity

Quinolones         -bactericidal
                   -E. coli, Enterobacter, Klebsiella, Proteus
                   (Not effective vs. Gm+ve & pseudomonas)
Fluoroquinolones   -bactericidal
                   -effective vs.Gr-ve (Haemophilus, Legionella,
                   Clamydia, Pseudomonas, Neisseria,
                   Enterobacteria), Gm+ve(S. aureus, S
                   epidermidis, Pseudomonas)
Nitrofurantoin     -bacteriostatic & bactericidal
                   -active vs. Gm+ve & Gm –ve (E. Coli,
                   Klebsiella, Proteus mirabilis, Enterobacter,
                   Staph., Strep faecalis)

Methenamine        -bactericidal
                   -effective vs. Gm-ve
                   (not effective vs. proteus)
    Pharmacokinetic properties
Antibiotic       ROA                 Metabolism &
                                     Excretion

Trimethoprim     PO                  M - liver
                                     E – kidney

Sulphonamides    PO                  Partly metab.
                                     E – kidney

Co-trimoxazole   PO, IV              M - liver
                                     E – kidney

penicillines     Amoxicillin,        M - liver
                 bacampicillin (PO),
                 ampicillin (PO, IV) E – kidney
     Pharmacokinetic properties
Antibiotic       ROA                  Metabolism &
                                      Excretion
Cephalosporins   Cephalexin (PO),     Majority not
                 cefaclor (PO),       metabolized
                 cefuroxime
                 (PO,IV), (cefixime   E – kidney
                 (PO), cefotaxime     (except
                 (IV)                 cefoperazone &
                                      ceftriazone -bile)
Quinolones       PO                   Partly metab.
                                      E - kidney
Fluoroquinolone Ciprofloxacin,        Partly metab.
                 ofloxacin,
                 levofloxacin         E - kidney
                 (PO,IV),
                 norfloxacin (PO)
   Pharmacokinetic properties

Antibiotic       ROA   Metabolism &
                       Excretion
Nitrofurantoin   PO    Partly metab.
                       Rapid excretion – kidney

Methenamine      PO    Form formaldehyde &
                       NH4+ (acidic urine)
                       E – kidney
                Adverse Effects
Antibiotic      Adverse effects                Contraindication

Trimethoprim    Hypersensitivity, antifolate
                S/E (megaloblastic
                anemia,thrombocytopenia
                granulocytopenia), N, V
Sulphonamides   Hypersensitivity,              Newborn,
                hemopoietic disturbances       baby < 2m/o,
                (granulocytopenia,             pregnant women at
                thrombocytopenia,              term,
                hemolytic anemia               pts on methenamine,
                (G6PD)), kernicterus           G6PD pt
                (neonate)
penicillines    Hypersensitivity, GIT(N, V,
                D) candidiasis,
                Nephritis(methicillin),
                pseudomembranous
                colitis(ampicillin)
               Adverse Effects
Antibiotic          Adverse effects      Contraindication

Cephalosporins      Hypersensitivity(<   h/o anaphylaxis to
                    penicillin)-10%      penicillins
                    cross-sensitivity,
                    superinfection
                    Disulfiram-like
                    effect & bleeding
                    (cefoperazone)
Quinolones      GIT(N,V,D),photos
                ensitivity, urticaria,
                CNS
Fluoroquinolone GIT(N,V,D), CNS( Pregnancy,
                h/a, dizziness)        lactating mother,
                photosensitivity,nep child <18 y/o
                hrotoxicity
             Adverse Effects
Antibiotic     Adverse effects       Contraindication
Nitrofurantoin GIT, hypersensitivity Pregnancy,
               (pneumonitis, rash)   neonates,
               neurological (h/a,    lactating mothers,
               nystagmus,            G6PD pt
               polyneuropathies),
               hemolytic anemia
               (G6PD)

Methenamine GIT,                    renal insufficiency
               ↑ dose -albuminuria, pt (M. mandelate),
               hematuria, rash      pt on sulfonamide
   ANTIBIOTICS –commonly
   used in UTI
Uncomplicated UTI
• Co-trimoxazole, amoxicillin, sulfisoxazole,
  fluoroquinolones
• Pregnant women – cephalosporins, sulfisoxazole
Recurrent cystitis
• Co-trimoxazole, trimethoprim, nitrofurantoin,
  cephalexin, ciprofloxacin
Complicated UTI
• Ampicillin, ciprofloxacin, levofloxacin
Acute pyelonephritis
• Ampicillin, ceftriaxone, co-trimoxazole,
  ciprofloxacin

				
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