Pharmacology Exam Notes: Antimicrobials, Antibiotics, TB & Insulin Overview (Questions & Answers)

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Antimicrobials-
 Used to treat infectious diseases
 190 million doses of antibiotics are given in hospitals each day
 Modern antimicrobials: 1930s and 1940s
 Significantly reduced morbidity and mortality from infection


Basic Principles of Antimicrobial Therapy
 Antibiotic
o Strictly speaking, a chemical produced by one microbe that can harm other
microbes
 Antimicrobial agent
o Any agent that can kill or suppress microorganisms
Selective Toxicity-
 Toxic to microbes but harmless to host
 Differences in the cellular chemistry of mammals and microbes
 Disruption of bacterial protein synthesis and cell wall
 Inhibition of an enzyme unique to bacteria

Classification of Antimicrobial Drugs-
 Various classification systems
 The two used for this textbook:
o Classification by susceptible organism
o Classification by mechanism of action

Prophylactic Use of Antimicrobials-
 Agents are given to prevent infection rather than to treat an established infection:
o Surgery
o Bacterial endocarditis
o Neutropenia
o Other indications

Misuses of Antimicrobial Drugs
 Attempted treatment of viral infections
 Treatment of fever of unknown origin
 Improper dosage
 Treatment in the absence of adequate bacteriologic information
 Omission of surgical drainage

Monitoring of Antimicrobial Therapy
 Monitor clinical responses and laboratory results
 Frequency of monitoring should increase with severity of infection
 Clinical indicators of success

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o Reduction of fever, resolution of signs/symptoms related to the affected organ
 Serum drug levels for toxicity


Classification of Antibiotics-
˜ Drugs work on:
 Cell wall synthesis
 Cell membrane permeability
 Protein synthesis (lethal)
 Nonlethal inhibitors of protein synthesis
 Synthesis of nucleic acids
 Antimetabolites
 Viral enzyme inhibitors

Classification of Antibiotics (Cont.)-
˜ Bacteriocidal
 Drugs are directly lethal to bacteria at clinically achievable concentrations
˜ Bacteriostatic
 Drugs can slow bacterial growth but do not cause cell death

Dosage Size and Duration-
 Antibiotic must be present:
o At the site of infection
o For a sufficient length of time
 Antibiotics must not be discontinued prematurely
 Teach patients to complete full prescription

Antibiotic Combinations-
 Antimicrobial effects of antibiotic combinations
o Additive, potentiative, antagonistic
 Indications
o Mixed infections, prevention of resistance, decreased toxicity, enhanced
bacterial action
 Disadvantages of combinations

Penicillins (Cont.)
 Action- Weaken the call wall of bacteria.
 Resistance- Is determined by inability to reach the target, inactivation by bacterial
enzymes and production of penicillin binding proteins that have a low affinity for it.
 Active against a variety of bacteria
 Direct toxicity: Low
 Principal adverse effect: Allergic reaction
 Structure includes a beta-lactam ring