Pharm Block 2 (Antimicro--gen and penicillins)

• oInhibit bacterial cell wall synthesis
• oInterfere with cell membrane function
• oDisrupt ribosomal function (protein synthesis) reversibly - generally bacteriostatic

oDisrupt ribosomal function (protein synthesis) irreversibly - generally bacteriocidal

• oInhibit nucleic acid metabolism
• oBlock enzyme pathways

To treat Viral Diseases, because it promotes resistance and my harm the recipient

If the initial concentration of certain specific bacterial pathogens is very high--> higher than usual doses of an antimicrobial agent may be required to clear the infection

• Static requires that the host defense mechanisms are intact in order for bacteriostatic antibiotics to be effective.
• _________________________________

Killing of bacteria continues after antibiotics are removed from the medium (usually because of the strong antibiotic binding to functional molecules within the organism)

• Time dependent
• Level serum and tissue levels

• Concentration dependent
• Hight peaks and low troughs

-is both time and dose dependent;

• Use of a single effective drug to prevent infection by one specific organism,
• Example: Rheumatic Fever, for CNS shunt surgery, meningococcal meningitis prophylaxis, PCP prophylaxis

enterobacter, citrobacter, seratia, pseudomonas, klebsiella, acinetobacter, and salmonella

-Production of antibiotic inactivating enzymes (B-Lactamases)

• -Changes in structure of target receptors (“Penicillin” Binding Proteins)
• -Increased efflux via drug transporters (Tetracycline efflux proteins)

-Decreased Microbial membrane permeability to antibiotics (Loss of Imipenem channels in Pseudomonas)

-Changes allowing organism to bypass metabolic steps

• Penicillin G
• Phenoxymethyl Penicillin (Pen V)

• Oxacillin 30% (A) P 0.5
• Nafcillin Variable P 0.5
• Cloxacillin 50% (A) 0 0.5
• Dicloxacillin 50% (A) 0 0.5

• Amoxicillin 75% 0 1.0
• Ticarcillin P 1.0
• Piperacillin P 1.2

-excreted in urine; excretion blocked by Probenecid

-Ampicillin partly and Nafcillin mostly excreted into the biliary tract

• Interfere with cell wall synthesis, by:
• –Binding to specific receptors (penicillin-binding proteins) located in the bacterial cytoplasmic membrane

–Inhibiting transpeptidase enzymes that act to cross-link linear peptidoglycan chains

–Activation of autolytic enzymes that cause lesions in the bacterial cell wall

-Formation of Beta Lactamases(penicillinases) that destroy the antimicrobial agents

-Mutation of penicillin binding protein targets

-Alter porins to decrease penetrations of antimicrobial agents

•Penicillin G and V

• •(Group A Strep) Strep pyogenes
• •(pneumococci) Strep pneumonia*
• •Some gram positive anaerobes*
• •(syphilis) Treponema pallidum

Nafcillin, Oxacillin, Cloxacillin, Dicloxacillin

• -Strep pneumo,
• -Listeria monocytogenes
• -Moraxella catarrhalis
• -Enterococci
• -Borellia bergdorfi

-Gram negative microbes especially pseudomonas*

• -Rheumatic fever prophylaxis
• -Syphilis
• _______________________
• Staphylococcal infections

• -Otitis media**
• -Sinusitis**
• -Pneumonia**
• -Urinary tract infections**
• -Lyme disease

-Mixed intra-abdominal infections **

• - Allergic hypersensativity (rash)
• -Diarrhea
• -Seizures
• -Haemotologic
• -nephritis
• -drug fever
• -Elevated Hepatic transaminases

RAST test for penicillin allergy is an important screening test.