Topic 12 - Pharmacology Flashcards
Define pharmacology
The study of drug action
Define antimicrobial agent
A drug for treating an infection
Define a chemotherapeutic agent
- A drug that acts against a particular disease (eg: antibiotics, insulin, anti-cancer)
What is Paul Ehrlich known for?
He had the idea of a “magic bullet” (a chemical compound that would kill a pathogen and not harm the host)
What drug did Paul Ehrlich co-discover?
Salvarsan (the first antibacterial drug), a cure for syphilis. It wasn’t the perfect drug as it contained arsenic
What are sulfonamides?
- Cured by stretococcal infections (by injection)
- Still in use today, although mostly replaced by penicillins
- Interferes with folic acid metabolism in Gram + bacteria
Who was alexander fleming?
- Treated pts with syphylis with Salvarsan
- Worked in inoculation department
- In 1928, his experiments were contaminated by the mould Peniciullum notatum
Alexander fleming grew what on one plate?
Staph and pen G
Selective toxicity is..
Key to a good antimicrobial agent
ie. we want to kill the microbe, not the host
Most Drugs
Less Drugs
Fewer Drugs
Bacteria
Fungi, Protozoa, Parasites
Viruses
What are the 5 things drug targets (bacterial)
A. Cell wall B. Cell membranes C. Protein Synthesis (translation) D. Nucleic acids E. Folic Acid metabolism
What does penicillin inhibit?
Peptidoglycan synthesis
What does Isoniazid inhibit?
Synthesis of mycolic acid
Where is mycolic acid found?
In cell walls of bacteria such as mycobacterium tuberculosis that stain acid fast
What does polymyxin do? (cell membrane)
Polymyxin targets specific lipids in the outer membrane of gram (-) bacteria
What do macrolides and tetracyclines bind to? (protein synthesis)
Specifically to prokaryotic ribosomes
What does the ribosome do?
It uses mRNA to make proteins
Where do macrolides bind on the prokaryote?
50S of the prokaryote and it blocks protein synthesis
Where do tetracyclines bind on the prokaryote?
30S of the prokaryote and it blocks protein synthesis
Where does streptomycin bind on the prokaryote?
30S of the prokayote and it blocks protein synthesis
What does fluoroquinolones inhibit? (Nucleic Acids)
DNA topoisomerase during DNA replication
What does sulfonamide inhibit?
Production of folate (folic acid)
Where is folic acid synthesized?
It is synthesized in bacteria, not humans
What are the two tests for testing for ABX resistance in bacteria?
- Disc diffusion test
- MIC (minimal inhibitory concentration) test
What test shows the zone of inhibition?
Disc diffusion test (it has discs of different ABX)
What do antiviral drugs target?
Target enzymes that are specific
Give an example of how antiviral drugs target enzymes?
Inhibit the replication of genetic material or protein processing and assembly
What is acyclovir used for?
Some DNA viruses (mostly for herpes virus infections)
What type of drug is acyclovir?
Antiviral (one of the most commonly used)
What does acyclovir inhibit?
viral DNA polymerase (not host polymerase)
What are the two antiviral drugs (Neuraminidase Inhibitors)
- Tamiflu
- Relenza
What do Reverse Transcriptase Inhibitors (RTIs) do? (Drug Targets of Viruses)
Inhibit reverse transcriptase (eg. HIV) (an enzyme unique to retroviruses)
What do Protease Inhibitors do?
Inhibit viral proteases (eg. HIV, hepatitis C) (an enzyme unique to viruses)
What are the 5 steps of viral protease?
- When virus starts reproducing it makes one long polypeptide
- Protease cuts at specific sites
- Shorter polypeptides fold into viral proteins
- Virus assembles
- When virus starts reproducing it makes one long polypeptide
What does ergosterol do?
It helps regulate membrane permeability and fluidity
What does Azoles inhibit?
Inhibits manufacture of ergosterole (a lipid unique to fungi and some protists)
What is Quinine effective against?
Malaria
What does Quinine interfere with?
Plasmodiums ability to metabolize hemoglobin
What does flagyl do?
- Chemically converted by an enzyme unique to some protists and anaerobic bacteria
- The chemical product damages DNA
What are things to consider with chemotherapeutic agents?
- Route of Administration
- Safety/Side effects (toxicity & allergies, disruption of normal flora)
- Cost
What does mebendazole block?
Microtubule formation and inhibits uptake of glucose
What may an anti-helminthes drug cause?
Paralysis of intestinal worms (they are unable to ‘hang on’)
