Transcript 04. Antibiotics-3.ppt

Miscellaneous Antibiotics
Polymyxins
 Active against gram-negative including
pseudomonas.
 Polymyxin B is only available.
 Bactericidal inhibits cell wall synthesis.
 Used only topically .
 Highly nephrotoxic.
Spectinomycin
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Bactericidal ,inhibits protein synthesis by
binding to 30S ribosomal subunits.
Active against gram positive & gram
negative organisms.
Rapidly absorbed after intramuscular
injection.
Excreted through kidney .
Clinical uses
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As an alternative treatment for drugresistant gonorrhea or gonorrhea in
penicillin –allergic patients.
No cross-resistance with other drugs used
in gonorrhea.
A single intramuscular dose is given
Adverse effects
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Pain at the site of injection
Fever And nausea
Nephrotoxicity ( rare )
Clindamycin
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Active against gram-positive cocci
Gram negative anaerobic organisms
Inhibits protein synthesis by binding to 50S
ribosomal subunits.
Pharmacokinetics
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Given orally or intravenously
Highly bound to plasma proteins
Distributes well into all body fluids &
tissues except brain &CSF.
Penetrates well into abscess & is taken up
by phagocytic cells.
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Metabolized by the liver.
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Both active drug & active metabolites are
excreted in bile & urine
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No dosage adjustment is needed for renal
failure.
Clinical uses
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Severe anaerobic infections ( bones and joints) .
Conjunctivitis.
In combination with aminoglycoside or
cephalosporin to treat penetrating wounds of
the abdomen & the gut.
Infections in female genital tract ( septic abortion
,pelvis abscess ).
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For prophylaxis of endocarditis in patients
with valvular heart disease
Plus primaquine is an effective alternative
to co-trimoxazole for moderate or severe
pneumocystis jiroveci pneumonia in AIDS
patients
Adverse Effects
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Diarrhea , nausea, Skin rash
Antibiotic-associated colitis
Impaired liver function
Neutropenia ( not common )
Vancomycin
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Bactericidal
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Inhibits bacterial cell wall synthesis
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Active on gram-positive bacteria including
β-lactamase producer & those resistant to
methicillin.
Pharmacokinetics
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Poorly absorbed from GIT
Slow IVI is used for treatment of systemic
infections.
Widely distributed
Cerebrospinal fluid levels are achieved in
meningeal inflammation
Excreted mainly through renal route
Clinical uses
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Endocarditis or sepsis mainly caused by
methicillin –resistant staphylococci.
Alternative to penicillin in enterococcal
endocarditis( in combination with gentamicin).
Meningitis( in combination with cephalosporin)
Orally only for the treatment of antibiotic associated enterocolitis
Adverse effects
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Phlebitis at the site of infusion
Fever
Ototoxicity & nephrotoxicity ( not
common).
Red man or red neck syndrome.
Hypotension
Bacitracin
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Bactericidal
Inhibits cell wall synthesis
Active against gram +ve organisms
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Used only topically in skin ,eye ,nose infections .
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As ointment in combination with polymyxin or neomycin
for mixed bacterial infections.
As solution in saline for irrigation of joints, wounds or
pleural cavity.
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Adverse Effects
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Highly nephrotoxic producing proteinuria,
hematuria
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Hypersensitivity reactions
Teicoplanin
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Similar to vancomycin in :
Mechanism of action
Antibacterial activity
Given I.M. or I.V.
long half-life(45-70 h).
once daily.
Cycloserine
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Bactericidal
Inhibits bacterial cell wall
Effective on gram- positive & gram- negative organisms as well as
M.tuberculosis.
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Rapidly absorbed orally
Widely distributed in body tissues & fluids.
Excreted as active form in urine
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Used in treatment of pulmonary & extrapulmonary tuberculosis
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C.N.S. toxicity ( headaches, tremors, acute psychosis, convulsions)
Contraindicated in epileptic & psychotic patients
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