PHAR 100 - Module 4 Flashcards
1
Q
antifungal → amophotericin B
A
- drug of choice for severe fungal infection
- binds to ergosterol, a steroid in the outer membrane of susceptible fungi that isn’t present in mammalian cells
- pores form, causing leakage across fungal membrane
- poorly absorbed from GI tract → administered via IV
- kidney toxicity potential
2
Q
antifungal → imidazoles (Azoles)
A
- effective when taken orally for systemic fungal infections
- inhibit a fungal cytochrome P450, inhibiting ergosterol synthesis
- higher affinity for fungal P450 than human P450
- can treat yeast infections
3
Q
the viral lifecycle
A
- take over operations of a cell in order to manufacture new viruses
- specific in the types of cells they infect (receptor dependent)
- instructions in virus DNA are transcribed to RNA
- protein-building machinery of host cell translates these instructions into the components of a new virus
- steps: 1) attachment, 2) entry, 3) replication, 4) biosynthesis, 5) assembly, 6) release
4
Q
drugs for influenza → amantidine
A
- inhibits the uncoating of viral DNA within infected cells, thereby preventing viral replication
- used for prevention of influenza due to the influenza A virus
5
Q
drugs for influenza → oseltamivir (Tamiflu)
A
- a neuroamininidase inhibitor, which is an enzyme that allows the spread of virus from cell to cell
- prevent neighbouring cells from getting sick
6
Q
drugs for HSV/VZV
A
- acyclovir inhibits DNA replication in infected cells
- drug of choice for infections caused by herpes (HSV)
- also useful in combatting infections due to varicella-zoster virus (VZV) - chicken pox and shingles
7
Q
antibiotics
A
- suppresses the growth of bacteria
- purpose is to stop a bacterial infection
- inhibits growth and reproduction of the bacteria (bacteriostatic effects) or directly kills the bacteria (bactericidal effects)
8
Q
gram-positive bacteria
A
thick peptidoglycan layer and no outer membrane
9
Q
gram-negative bacteria
A
thin peptidoglycan layer and an outer membrane
10
Q
classification of antibiotics
A
- classified based on the spectrum of microorganisms affected
→ narrow spectrum - only useful against particular species of microorganisms (penicillin G and gram-positive bacteria)
→ broad spectrum - effective against a wide range of microorganisms (tetracyclines) - and classified based on the biochemical pathway targeted in the microorganism
11
Q
targets of antibiotics
A
- cell wall and cell membrane synthesis
- protein synthesis
- nucleic acid metabolism
12
Q
penicillins mechanism of action
A
- target cell wall and cell membrane synthesis
- interferes with new bacterial cell wall formation, and the resulting cells are formed without cell walls (protoplasts)
- human cells don’t have cell walls and are unaffected
13
Q
penicillins adverse effects
A
- allergic reaction
- rash, diarrhea, fever
14
Q
types of penicillin
A
- natural: penicillin G (narrow spectrum, destroys gram-positive bacteria, used in pneumonia, middle ear infections, skin infections)
- semisynthetic (modified penicillin G):
→ penicillin V (more stable with stomach acid, better for oral administration)
→ methicillin (is resistant to attacks by penicillinase)
→ ampicillin and amoxacillan (broader spectrum, useful agonist against a range of infections caused by gram-negative bacteria)
→ augmentin (combination of semisynthetic penicillin and an inhibitor of penicillinase, effective against penicillinase-producing strains of bacteria)
15
Q
cephalosporins
A
- more resistant to penicillinase than is the penicillin group
- selective inhibitors of bacterial cell wall synthesis
16
Q
penicillins and cephalosporins mechanism of action
A
- in bacterial cell wall synthesis, an enzyme called a transpeptidase cross-links the 2 peptide chains using D-alanine-D-alanine in the reaction to form a strong, stable cell wall
- penicillins and cephalosporins resemble D-alanine-D-alanine in structure and compete with them for the enzyme, and thus inhibit the enzyme
- without cross-linking, the cell isn’t functional
