Penicillins Flashcards
Penicillin Mechanism
Bactericidal
Inhibits cell wall synthesis
Penicillin classification
1. Natural penicillin: Penicillin G (Benzyl pen) Penicillin V (phenoxy Methyl Pen)
2. Penicillinase resistant Penicillins: Methicillin Nafcillin Oxacillin Cloxacillin
- Amino penicillins:
Amoxicillin
Ampicillin - Extended spectrum penicillin:
Piperacillin (carboxy)
Ticarcillin (ureido penicillin)
Natural Penicillin spectrum
G +ve cocci
Some gram -ve cocci
Pen G more active than Pen V against G -ve organisms
Readily hydrolyzed by B lactamses
Natural Penicillin
Therapeutic use
S pneumoniae : Pneumonia Arthritis Meningitis Peritonitis Pericarditis Osteomyelitis Mastoiditis Pharyngitis Otitis media Sinusitis Bacteremia
Pen G preferred for: Gonococcal inf Syphilis Anthrax Actinomycosis Gas gangrene Listeria inf.
Natural Penicillin administration
Pen G: Oral, IV, IM… Na , K salts
Pen V: only Oral
Pen G procaine & Pen G benzathine : respiratory or IM
Natural Penicillin
Side effects
Hypersensitivity: Rash, urticaria, scarlantinoform, rarely thrombocytopenic purpura
Anaphylaxis: hypotn, airway constriction, nausea, vomit, serum sickness, angioedema, eosinophila
GI distress: nausea diarrhea
Bone marrow suppression: impaired platelet aggregation, Agranulocytosis, superinfection
Seizures: HIGH DOSE especially in renal impairment
Natural Penicillin
Interactions
Probenecid
Antibiotic antagonism if Erythromycin, tetracycline, chloramphenicol given within 1 hr
G procaine amd benzathine with caution due to hypersensitivity and prolonged action
Parenteral product contain K (1.7mEq/million unit) or Na (2mEq/million unit)
Penicillinase resistant Penicillins
Spectrum
Staphylococci
Not MRSA
PRPs
Indications
Staphylococcal inf. Endocarditis Osteomyelitis Skin Soft tissue inf.
PRPs
Precautions
Hypersensitivity
Methicillin : Nephrotoxicity & interstitial Nephritis
Oxacillin Nafcillin : hepatotoxic
PRPs interaction
Probenecid increases penicillin blood levels. Maybe given sometimes for that purpose
Amino penicillin
Broad spectrum Penicillins
Spectrum
Similar to natural pen spectrum but broader
Destroyed by B lactamses (so given in Combo)
Gonococci (neisseria gonorrhoea) Shigella Listeria E coli Proteus Salmonella H. pylori H. Influenzae
Amino penicillin
Indications
Amoxicillin: (well absorbed from gut) Upper respiratory tract inf Uncomplicated UTIs Gonorrhea Otitis media Meningitis
Ampicillin: (not well absorbed from gut) Shigellosis Listeria Pneumonia Septicemia Bacteroid fragillis inf.
Amino penicillin combos
Amoxicillin + Clavulanic acid (Augmentin)
Ampicillin + Sulbactam (Unasyn)
Amino penicillin combos
Amoxicillin + Clavulanic acid (Augmentin)
Amino penicillin
Side effects
Hypersensitivity
Diarrhea (Ampicillin)
Amino penicillin
Interactions
Probenecid : blood level of Pen increase
Maybe used to increase plasma levels of Penicillin
Extended spectrum penicillin (Anti-pseudomonal Pen)
Spectrum
Ticarcillin: (with Clavulanic acid)
P.aeroginosa
Piperacillin:
More activity against P than ticarcillin
Piperacillin + tazobactam: Enhances spectrum Staphylococcus Haemophilus Bacteroid Enterobacter
Extended spectrum penicillin (Anti-pseudomonal Pen)
Indications
Serious G -ve infection Sepsis Pneumonia Abdominal inf Bone & soft tissue infection Nosocomial pneumonia (hosp acquired pneumonia)
Extended spectrum penicillin (Anti-pseudomonal Pen)
Side effects
Hypersensitivity
Ticarcillin : hypokalemia, high Na content in Ticarcillin dangerous for HF
Inhibit platelets aggregation –> bleeding
Extended spectrum penicillin (Anti-pseudomonal Pen)
Interactions
Probenecid
