PHM203 (ID) - Allergies, PK, SSTIs, C. Diff, Influenza,
Pneumonia, TB, Antifungals, MDROs: Q’s & A’s
Tips For The Midterm:
Focus on treatments. Learn spectrum cause it's easy to understand treatment
once you learn spectrum. Questions are case-based, similar to derm. Antibiotic
spectrum questions were only based on the ones emphasized in class.
True or false: all adverse drug reactions are drug allergies. Right Ans -
False.
Predictable drug reactions (e.g. GI upset) is dose dependent and not an
allergic reaction.
What are the most common types of allergic reactions? Right Ans - Type IV:
delayed onset (days to weeks) and symptoms include contact dermatitis and
maculopapular rash.
- repeated exposure causes same rxn
Type I: onset within 1 hour and symptoms include urticaria, anaphylaxis
- repeated exposure may cause worse rxn
When is skin testing indicated? Right Ans - For IgE-mediated reactions.
Describe the drug-viral interaction with ampicillin. Right Ans - 60-100% of
patients with infectious mononucleosis, lymphocytic leukemia, CMV infection,
and concurrent allopurinol will develop a nonspecific morbilliform eruption.
True or false: risk of reacting to cephalosporins in a patient with a history of a
penicillin allergy is less than 1%. Right Ans - True.
The R groups cause the cross-reactivity, rather than the beta-lactam group.
In a patient with type 1 allergy to penicillin, it is still advised to avoid all
cephalosporins if an alternative is available.
True or false: fever is a predictor of a more serious drug reaction. Right Ans
- True.
Other red flags include: mucous-membrane involvement (blisters), facial
edema, lymphadenopathy.
,True or false: cross-reactions between sulfonamide antibiotics and non-
antibiotic sulfonamides is common. Right Ans - False.
The sulfonamide group does not cause cross-reactivity.
Instead, the aromatic amine (-NH2) group is thought to cause the allergic
reaction.
What is a suspension? Right Ans - Coarse dispersion containing finely
divided insoluble material uniformly suspended in a continuous (liquid)
phase.
Reasons for making:
- oral administration of insoluble drugs
- improve stability
- mask bitter taste of parent drug
- ease oral administration
- some drugs need to be present in the finely divided form to maximize
surface area
What are ideal characteristics of a suspension? Right Ans - - Suspended
material should not settle rapidly
- Particles that do settle should be readily redispersed
- Suspension should not be too viscous to pour freely from the orifice of the
bottle or to flow through a syringe needle
- Suspended particles must be small and uniformly distributed
True or false: most medicinal materials are hydrophobic. Right Ans - True.
Therefore, some wetting material should be used to allow proper formation of
suspension. Wetting agents should have an HLB 7-9 (e.g. alcohol, glycerin,
surfactants).
Which suspension settles faster: deflocculated or flocculated? Right Ans -
Flocculated.
However, flocculated suspensions can be easily resuspended. In a flocculated
suspension, zeta is ~0.
Deflocculated suspensions will form a hard cake at the bottom of the
container which will be difficult/impossible to redisperse.
What are ideal characteristics of a preservative agent in a suspension?
Right Ans - - Effective against a wide spectrum of microorganisms
,- Neutral charge so they can penetrate membrane of bacteria/microorganism
- Stable
- Nontoxic
- Compatible
- Free of taste and odor
Which organisms are regularly found on the skin? Right Ans - Gram
positive:
- Coagulase-negative Staphylococci
- Micrococcus
- Corynebacterium
- Propionibacterium
- Staphylococcus aureus
Gram negative:
- Acinetobacter
Fungi:
- Malassezia
- Candida
List risk factors for SSTIs. Right Ans - - Too much/not enough skin
moisture
- High concentration of colonizing bacteria
- Poor blood supply
- Supplies of bacterial nutrients
- Damage to epidermal layer
What are the most common organisms which cause wound infections? List
from most prevalent to least prevalent, and sort by gram positive/negative.
Right Ans - Gram positive:
- MRSA
- MSSA
- GAS
- Staphylococcus lugdunensis/Coagulase negative staph (CONS)
- Enterococcus faecium
Gram negative:
- Pseudomonas aeruginosa
, - Escheria coli
How can one screen for MSSA? Right Ans - Treat organism with
oxacillin/cloxacillin. If the organism is sensitive to oxacillin/cloxacillin, it will
predict cefazolin and cefuroxime susceptibility.
I say oxacillin/cloxacillin because the notes contradict each other.
What is the mechanism of action of MRSA resistance? Right Ans - There is a
mecA gene that causes mutation in PBP. This prevents beta-lactams from
binding.
The gene spreads horizontally (through mobile gene element).
Which exotoxin is associated with community-acquired MRSA? Right Ans -
Panton-Valentine Leukocidin (PVL) exotoxin.
It causes breakdown of skin and causes abscess and tissue necrosis.
Since CA-MRSA is associated with PVL, CA-MRSA is more virulent.
Which is more susceptible to first-line drugs, CA-MRSA or HA-MRSA? Right
Ans - CA-MRSA.
What is difference between primary and secondary SSTIs? Right Ans -
Primary:
- previously healthy skin
- single pathogen
Secondary:
- damaged skin
- polymicrobial
What are the characteristics of complicated SSTIs? Right Ans - SSTI
presenting with:
- infected ulcer
- burns
- cellulitis with associated abscesses
Briefly describe characteristics of impetigo infection. Right Ans - - Highly
contagious superficial skin infection
- 7-10 day incubation period
Pneumonia, TB, Antifungals, MDROs: Q’s & A’s
Tips For The Midterm:
Focus on treatments. Learn spectrum cause it's easy to understand treatment
once you learn spectrum. Questions are case-based, similar to derm. Antibiotic
spectrum questions were only based on the ones emphasized in class.
True or false: all adverse drug reactions are drug allergies. Right Ans -
False.
Predictable drug reactions (e.g. GI upset) is dose dependent and not an
allergic reaction.
What are the most common types of allergic reactions? Right Ans - Type IV:
delayed onset (days to weeks) and symptoms include contact dermatitis and
maculopapular rash.
- repeated exposure causes same rxn
Type I: onset within 1 hour and symptoms include urticaria, anaphylaxis
- repeated exposure may cause worse rxn
When is skin testing indicated? Right Ans - For IgE-mediated reactions.
Describe the drug-viral interaction with ampicillin. Right Ans - 60-100% of
patients with infectious mononucleosis, lymphocytic leukemia, CMV infection,
and concurrent allopurinol will develop a nonspecific morbilliform eruption.
True or false: risk of reacting to cephalosporins in a patient with a history of a
penicillin allergy is less than 1%. Right Ans - True.
The R groups cause the cross-reactivity, rather than the beta-lactam group.
In a patient with type 1 allergy to penicillin, it is still advised to avoid all
cephalosporins if an alternative is available.
True or false: fever is a predictor of a more serious drug reaction. Right Ans
- True.
Other red flags include: mucous-membrane involvement (blisters), facial
edema, lymphadenopathy.
,True or false: cross-reactions between sulfonamide antibiotics and non-
antibiotic sulfonamides is common. Right Ans - False.
The sulfonamide group does not cause cross-reactivity.
Instead, the aromatic amine (-NH2) group is thought to cause the allergic
reaction.
What is a suspension? Right Ans - Coarse dispersion containing finely
divided insoluble material uniformly suspended in a continuous (liquid)
phase.
Reasons for making:
- oral administration of insoluble drugs
- improve stability
- mask bitter taste of parent drug
- ease oral administration
- some drugs need to be present in the finely divided form to maximize
surface area
What are ideal characteristics of a suspension? Right Ans - - Suspended
material should not settle rapidly
- Particles that do settle should be readily redispersed
- Suspension should not be too viscous to pour freely from the orifice of the
bottle or to flow through a syringe needle
- Suspended particles must be small and uniformly distributed
True or false: most medicinal materials are hydrophobic. Right Ans - True.
Therefore, some wetting material should be used to allow proper formation of
suspension. Wetting agents should have an HLB 7-9 (e.g. alcohol, glycerin,
surfactants).
Which suspension settles faster: deflocculated or flocculated? Right Ans -
Flocculated.
However, flocculated suspensions can be easily resuspended. In a flocculated
suspension, zeta is ~0.
Deflocculated suspensions will form a hard cake at the bottom of the
container which will be difficult/impossible to redisperse.
What are ideal characteristics of a preservative agent in a suspension?
Right Ans - - Effective against a wide spectrum of microorganisms
,- Neutral charge so they can penetrate membrane of bacteria/microorganism
- Stable
- Nontoxic
- Compatible
- Free of taste and odor
Which organisms are regularly found on the skin? Right Ans - Gram
positive:
- Coagulase-negative Staphylococci
- Micrococcus
- Corynebacterium
- Propionibacterium
- Staphylococcus aureus
Gram negative:
- Acinetobacter
Fungi:
- Malassezia
- Candida
List risk factors for SSTIs. Right Ans - - Too much/not enough skin
moisture
- High concentration of colonizing bacteria
- Poor blood supply
- Supplies of bacterial nutrients
- Damage to epidermal layer
What are the most common organisms which cause wound infections? List
from most prevalent to least prevalent, and sort by gram positive/negative.
Right Ans - Gram positive:
- MRSA
- MSSA
- GAS
- Staphylococcus lugdunensis/Coagulase negative staph (CONS)
- Enterococcus faecium
Gram negative:
- Pseudomonas aeruginosa
, - Escheria coli
How can one screen for MSSA? Right Ans - Treat organism with
oxacillin/cloxacillin. If the organism is sensitive to oxacillin/cloxacillin, it will
predict cefazolin and cefuroxime susceptibility.
I say oxacillin/cloxacillin because the notes contradict each other.
What is the mechanism of action of MRSA resistance? Right Ans - There is a
mecA gene that causes mutation in PBP. This prevents beta-lactams from
binding.
The gene spreads horizontally (through mobile gene element).
Which exotoxin is associated with community-acquired MRSA? Right Ans -
Panton-Valentine Leukocidin (PVL) exotoxin.
It causes breakdown of skin and causes abscess and tissue necrosis.
Since CA-MRSA is associated with PVL, CA-MRSA is more virulent.
Which is more susceptible to first-line drugs, CA-MRSA or HA-MRSA? Right
Ans - CA-MRSA.
What is difference between primary and secondary SSTIs? Right Ans -
Primary:
- previously healthy skin
- single pathogen
Secondary:
- damaged skin
- polymicrobial
What are the characteristics of complicated SSTIs? Right Ans - SSTI
presenting with:
- infected ulcer
- burns
- cellulitis with associated abscesses
Briefly describe characteristics of impetigo infection. Right Ans - - Highly
contagious superficial skin infection
- 7-10 day incubation period
