Pharmacology Chapter 8-9

drug class that targets foreign organisms by the process of selective toxicity (affect proteins or enzymes characteristic of foreign organisms but not used by human cells.

• 1. Interere with biosynthesis of the cell wall (penicillins)
• 2. Block use of substances necessary for cell growth and development (sulfonamides)
• 3. Interference with protein synthesis so hinders cell division (aminoglycosides)
• 4. Interferes with DNA synthesis so unable to devide (fluoroguinolones)
• 5. Alter cell permeability (antifungals, antiprotozoans)

only works on a few types of infections

works on wide range of organisms across many types of infections

cause cell death of bacteria

control growth of the bacteria and then the immune system takes care of it

preventative antibiotic

human immune reponse can counter and remove invading organisms

if the mechanism of action of the drug is aimed at a process that the foreign organism does not use

organisms develop over time resistance to drugs that used to be effective

Bacteria can produce enzyme that deactivate the drug (production of penicillinase by bacteria against penicillin)

Alter cellular permeability

Alter binding sites on membranes or ribosomses

Produce a chemical that antagonizes the drug action

• 1. Identify the pathogen through culture
• 2. Determine sensitivity
• 3. Multiple antibiotics sometimes used to treat systemic infection 

• 1.   Kidney toxicity
• 2.   GI toxicity (Nausea/Vomiting/Diarrhea)
• 3.   Neurotoxicity (dizziness, hearing, lethargy)
• 4.   Hypersensitivity/Allergy
• 5.   Superinfections
• Multidrug Resistant Organisms (TB, Gonorria , MRSA)

• - drugs that inhibit or kill bacteria

positive

negative

positive

negative

• Penicillins (B lactam drugs) and cephalosporings.  (Beta Lactam drugs have a beta lactam ring in center and include PCN, cephalosporins, carbapenems)

• inhibit needed enzymes, introduce defective building blocks, destroy sequencing of DNA.  Quinolones,  Metronidazole

• - block folate pathway and inhibit production of DNA, RNA, protein.  Sulfonamides

• target several steps such as copying mRNA code, target actual ribosomal synthesis of mRNA.  Can bind to normal human cell ribosomes in rapidly dividing GI, skin, and bone marrow, kidney and liver and cause toxicities.  Aminoglycosides, macrolides, TCN.
•  

GI

8-10

Gentamicin

Cefaclor

Ciprofloxacin

Erythromycin

Amoxicillin

Sulfasalzine

tetracycline

isoniazid