Theme 7 - Chemotherapeutic agents introduction Flashcards
Define chemotherapy
The use of natural or synthetic chemicals to kill or inhibit bacteria, viruses, fungi, protozoa and helminths in the human body (that are causing harm).
Define chemotherapy in terms of cancer
The use of chemicals to inhibit the growth of malignant or cancerous cells within the body.
What are the 4 groups of chemotherapeutic drugs?
Antibacterial
Antifungal
Antiviral
Antiparasitic
What can the term “antibiotic” be defined as?
A chemical substance that is produced by a microorganism and has the ability to kill or inhibit the growth of other microorganisms.
What is an antibiotic? (in terms of chemotherapy)
Chemotherapeutic agents that are used systemically to treat bacterial and related infections can be described as antimicrobial or more specific as antibacterial drugs.
All antibiotics are antimicrobials; but not all antimicrobials are antibiotics
What is the primary goal of chemotherapy?
The drugs that are used clinically must be selectively toxic for bacteria, fungi, protozoa, viruses, helminths and cancer cells without harming the host cells.
What is the success of selective toxicity is based on?
The exploitation of biochemical differences between prokaryotes and eukaryotes.
List 4 examples of exploitation of biochemical differences between prokaryotes and eukaryotes
- Presence of mucopolypeptide-containing cell wall in bacteria vs. cell membranes in eukaryotes
- 70S ribosomes in bacteria vs. 80S ribosomes in eukaryotes
- Unique enzymes in bacteria
- Unique metabolic reactions in the cytoplasm of microorganisms
What do selectively toxic chemotherapeutic agents have?
A wide therapeutic index and little/no toxicity in normal cells.
What do Bactericidal antibiotics do?
cause microbial lysis and cell death
What do Bacteriostatic antibiotics do?
inhibit cell growth
Define bacterial resistance
When bacterial growth is unaffected by an antibacterial agent- resulting in poor therapeutic response
What does the term Narrow-action spectrum mean?
When only a few bacterial cell types are affected.
What does the term Broad-spectrum mean?
When various bacterial cell types are affected
What does the term Developing resistance mean?
Under the influence of antibiotics, sensitive bacterial
cultures can undergo genetic transformation (mutation) to form resistant cultures. Sensitive cell types will be killed by the agent but mutant cells will increase.
What does the term Multi-resistant bacteria mean?
Repeated administered antibiotics (e.g. in hospitals) will increase the possibility of the development of resistant bacteria.
What is Plasmid-resistance?
Closed loops of DNA that are responsible for resistance towards antibiotics can be transferred between resistant bacteria by processes such as conjugation and transduction.
Define spectrum of activity
The range of targets against which a drug is biologically active.
What are 2 fundamental concepts of importance surrounding pharmacokinetics of antimicrobial drugs?
- Concentration dependent bacterial killing effects
- Time dependent bacterial killing effects
What is MIC (minimal inhibitory concentration)?
The lowest concentration of an antibiotic that inhibits the growth of a given strain of bacteria.
What must be done to drugs to increase the rate of bacterial killing effects if a drug has “concentration dependent bacterial killing effects”?
The concentration must be increased above the MIC, it does not matter how long the concentration stays above the MIC.
What must be done to drugs to increase the rate of bacterial killing effects if a drug has “Time dependent bacterial killing effects”?
The total time that the concentration of the drug is above the MIC must be increased, it does not matter if the drug level is just barely above the MIC or is 10 times the MIC.
