Exam 4: Antimicrobial Drugs Flashcards
Drugs are chemicals that
affect physiology in any manner
Chemotherapeutic agents are drugs that
act against diseases
Antimicrobial agents are drugs that
treat infections
Examples of drugs
medications, caffeine, alcohol, tobacco
Examples of chemotherapeutic agents
insulin, anticancer drugs, antimicrobials
Examples of Antimicrobial agents
antibiotics, antivirals, anti protozoans, antifungals, antihelminthics
The key to antimicrobial action is
selective toxicity
Selective toxicity
more toxic to pathogen than to the pathogen’s host
The largest number and diversity is found in
antibacterial drugs
there are ______ drugs available to treat eukaryotic infections
fewer
The least amount of medication is available for
viral infections
Mechanisms of Action of Antimicrobial drugs
- Selectively toxic to fungal or bacterial cells with cell walls
- Disrupt translation (target dif. in ribosomes)
- Damage membrane integrity
- Pathways not used by humans
- Analogs: incorporated into DNA/RNA of pathogens, distort nucleic acids, prevent further processing
- blocked by peptide and sugar analogs of attachment of receptor proteins; especially viruses
Drugs can selectively target translation without affecting eukaryotes BUT
it can be harmful because mitochondria of animals and humans contain 70S ribosomes
examples of drugs inhibiting protein synthesis
tetracycline, monocycine, doxycycline, azithromycin, erythormycin
Clinical Considerations in prescribing antimicrobials
- Spectrum of Action
- Safety and Side effects
- Resistance
Spectrum of action
number of different pathogens a drug acts against
Narrow spectrum is effective against _____ organisms while broad-spectrum is effective against ______ organisms
few; many
Side effects are ________ effects
unanticipated
Adverse Reactions
negative side effects
Allergies are ______ but can be life threatening and include:
rare, anaphylactic shock
Toxicity
drugs can be toxic to kidneys, liver, and lungs, and extra caution should be taken when prescribing to pregnant women
Clinical considerations including safety and side effects
- Disrupts normal microbiota
- Overgrowth of normal flora can cause a secondary infection
- Mostly a concern in hospitalized patients
Some pathogens are naturally resistant while some can acquire resistance in 2 ways
- New mutations of chromosomal genes
2. Acquisition of R-plasmids via horizontal gene transfer
Multiple resistance
pathogen an acquire resistance to more than one drug; called “superbugs”
Cross resistance
resistance to one antimicrobial ages may confer resistance to similar drugs
Retarding/Decreasing resistance to antimicrobial drugs
maintain high concentration of drug in patient for a sufficient time and use antimicrobial agents in combination
Synergism
one drug enhances effect of second drug
To decrease resistance to antimicrobial drugs, antimicrobials should
only be used when necessary
New variations of drugs are developing to help
decrease resistance
2nd and 3rd generation drugs
Quorum sensing and bacteriocins
new antibiotics being developed because of antibiotic resistance
quorum sensing is bacterial communication chemicals
