Mid Semester Exam Blueprint
Green: Cvek’s Review
Community Acquired Pneumonia
- Empiric therapy: initiation of treatment based on clinical experience and evidence before
specific microbial identification and susceptibility testing
- Occurs before cx and sensitivity
- Guided by patient’s sx and pathogen site
- Therapy will then be adjusted post cx & sensitivity
- E.g. Cephalosporins or Azithromycin or Fluoroquinolones
- Streptococcus pneumoniae: the leading cause of CAP → resistant to penicillin,
cephalosporins, macrolides, and trimethoprim-sulfamethoxazole
- vancomycin and newer quinolones are still effective against most strains
- Enterobacteriaceae: EX: E. coli and Klebsiella → usually susceptible to standard
CAP antibiotics, but amoxicillin/clavulanic acid has high resistance rates
- P. aeruginosa: gram-negative bacterium, difficult to treat due to intrinsic antibiotic
resistance and adaptability
- Reasons for resistance: overuse or misuse of antibiotics, inadequate duration of
therapy (not completing course)
- Penicillin allergy and cross sensitivities
- Cross-sensitivity: reactions with drugs that have similar structures or functions
- Cephalosporins: structurally related to penicillin, higher risk with first-generation
(like cephalexin), later generations have lower rates of cross-reactivity
- Other Beta-Lactams: carbapenems and monobactams have varying degrees of cross-
sensitivity
- Penicillin allergy can be associated with worse clinical outcomes for bacterial
pneumonia → hospitalization, acute respiratory failure, intubation, mortality →
take levofloxacin instead
- Alternative antibiotics include doxycycline (a tetracycline) or clarithromycin (a
macrolide)
- Antibiotic Side Effects
- Adverse effects of Erythromycin, Azithromycin(Zithromycin), clarithromycin
(Biaxin): abdominal cramping, anorexia, diarrhea & vomiting, allergic reaction
- All: GI disruptions & potential allergy
- Penicillin: Anaphylaxis
- Tetracycline (doxycycline): photosensitivity and teeth staining
- Macrolides (azithromycin/erythromycin): QT prolongation and hepatotoxicity
- Fluoroquinolones (Levofloxacin): Tendon rupture
- Aminoglycosides (gentamicin): Ototoxicity and nephrotoxicity
,- Cephalosporins MOA: beta-lactam antibiotics, structurally and chemically related to the
penicillins.
- Inhibition of Peptidoglycan Synthesis: Cephalosporins bind to penicillin-binding
proteins (PBPs), which are essential for the synthesis of peptidoglycan, a crucial
component of bacterial cell walls
- Cell Lysis: As the bacterial cell wall becomes compromised, the osmotic pressure
inside the cell causes it to swell and eventually burst, resulting in cell lysis.
- Examples of Cephalosporins (start with cef- or ceph-):
- Cefazolin
- Cefdinir
- Cefpodoxime
- Fluoroquinolones drug-food interactions
- Reduce absorption and effectiveness of the drug - substances that bind to the drug in
the GI tract
- Dairy Products: Calcium-rich foods can bind to fluoroquinolones, reducing their
absorption→ avoid taking antibiotics two hours before or after dairy
- Iron and Zinc Supplements: iron and zinc can chelate fluoroquinolones, decreasing
bioavailability
- Antacids: Antacids that contain aluminum, magnesium, or calcium can interfere with
fluoroquinolone absorption
- Administer fluoroquinolones 2 hours before or 6 hours after consuming these foods
- Examples of Fluoroquinolones (end in -xacin):
- Ciprofloxacin
- Levofloxacin
- Moxifloxacin
- Macrolide antibiotics (end in -mycin): commonly used to treat community-acquired
pneumonia (MOA: Inhibition of bacterial protein biosynthesis)
- Azithromycin: treats mild pneumonia, more tolerable, may be administered in a short
course
- Clarithromycin: better activity against Haemophilus influenza and Moraxella
catarrhalis
- Erythromycin: can be used during pregnancy.
- First choice for CAP because they provide good coverage for the most likely
organisms that cause the disease
- Considerations: GI upset, drug interactions, give to people under 60, non-smokers
- Monitoring for therapeutic efficacy of antibiotics
- Clinical criteria: fever, respiratory rate, O2, T, as well as mental status and ability to
eat
- Biomarkers: CRP and procalcitonin
- Chest x-ray: to confirm pneumonia has resolved
, - 48-72 hours improvement
- Antibiotics that can cause C Diff.
- Clindamycin: traditional high-risk antibiotic for C. diff
- Cephalosporins (cefdinir and cefpodoxime), fluoroquinolones, penicillins, and
nitrofurantoin
- Fluoroquinolones, macrolides, cephalosporins, clindamycin
Hypothyroidism
- Levothyroxine dosing in special populations
- Pregnancy:
- Thyroid hormone replacement should be prescribed to all pregnant women
because the benefits outweigh the risks
- Pregnant women have an increased metabolic rate → provider should
increase the maintenance dose by 25% to provide adequate coverage
- TSH levels should be monitored q4 weeks
- Levothyroxine is recommended as opposed to combination T3 and T4
medications (which lower maternal TSH levels → fetal neurological
suppression)
- Elderly
- May require smaller doses due to cardiac disruption (e.g. tachycardia,
angina) → require more frequent monitoring
- Drug-Drug interactions
- Bile acid sequestrants, iron salts, and antacids decrease the absorption of po thyroid
preparations
- Estrogens increase TBg → may decrease response to thyroid hormones
- Monitoring for therapeutic efficacy (TSH and T4)
- Thyroid Hormone Synthesis: Decreased T4 stimulates the synthesis of TSH →
TSH stimulates thyroid gland to produce thyroid hormone
- TSH: Primary lab parameter used to measure efficacy of Levothyroxine
- Normal Range: 0.3 to 5 mlU/L
- If elevated → insufficient dosing → hypothyroidism
- If decreased → overdosing → hyperthyroidism
- T4:
- Normal Range: 0.7 to 1.86 ng/dL
- If elevated → hyperthyroidism
- If decreased → hypothyroidism
- TSH level should be evaluated at initiation of therapy and q4-8 weeks until a stable
euthyroid state is reached
Green: Cvek’s Review
Community Acquired Pneumonia
- Empiric therapy: initiation of treatment based on clinical experience and evidence before
specific microbial identification and susceptibility testing
- Occurs before cx and sensitivity
- Guided by patient’s sx and pathogen site
- Therapy will then be adjusted post cx & sensitivity
- E.g. Cephalosporins or Azithromycin or Fluoroquinolones
- Streptococcus pneumoniae: the leading cause of CAP → resistant to penicillin,
cephalosporins, macrolides, and trimethoprim-sulfamethoxazole
- vancomycin and newer quinolones are still effective against most strains
- Enterobacteriaceae: EX: E. coli and Klebsiella → usually susceptible to standard
CAP antibiotics, but amoxicillin/clavulanic acid has high resistance rates
- P. aeruginosa: gram-negative bacterium, difficult to treat due to intrinsic antibiotic
resistance and adaptability
- Reasons for resistance: overuse or misuse of antibiotics, inadequate duration of
therapy (not completing course)
- Penicillin allergy and cross sensitivities
- Cross-sensitivity: reactions with drugs that have similar structures or functions
- Cephalosporins: structurally related to penicillin, higher risk with first-generation
(like cephalexin), later generations have lower rates of cross-reactivity
- Other Beta-Lactams: carbapenems and monobactams have varying degrees of cross-
sensitivity
- Penicillin allergy can be associated with worse clinical outcomes for bacterial
pneumonia → hospitalization, acute respiratory failure, intubation, mortality →
take levofloxacin instead
- Alternative antibiotics include doxycycline (a tetracycline) or clarithromycin (a
macrolide)
- Antibiotic Side Effects
- Adverse effects of Erythromycin, Azithromycin(Zithromycin), clarithromycin
(Biaxin): abdominal cramping, anorexia, diarrhea & vomiting, allergic reaction
- All: GI disruptions & potential allergy
- Penicillin: Anaphylaxis
- Tetracycline (doxycycline): photosensitivity and teeth staining
- Macrolides (azithromycin/erythromycin): QT prolongation and hepatotoxicity
- Fluoroquinolones (Levofloxacin): Tendon rupture
- Aminoglycosides (gentamicin): Ototoxicity and nephrotoxicity
,- Cephalosporins MOA: beta-lactam antibiotics, structurally and chemically related to the
penicillins.
- Inhibition of Peptidoglycan Synthesis: Cephalosporins bind to penicillin-binding
proteins (PBPs), which are essential for the synthesis of peptidoglycan, a crucial
component of bacterial cell walls
- Cell Lysis: As the bacterial cell wall becomes compromised, the osmotic pressure
inside the cell causes it to swell and eventually burst, resulting in cell lysis.
- Examples of Cephalosporins (start with cef- or ceph-):
- Cefazolin
- Cefdinir
- Cefpodoxime
- Fluoroquinolones drug-food interactions
- Reduce absorption and effectiveness of the drug - substances that bind to the drug in
the GI tract
- Dairy Products: Calcium-rich foods can bind to fluoroquinolones, reducing their
absorption→ avoid taking antibiotics two hours before or after dairy
- Iron and Zinc Supplements: iron and zinc can chelate fluoroquinolones, decreasing
bioavailability
- Antacids: Antacids that contain aluminum, magnesium, or calcium can interfere with
fluoroquinolone absorption
- Administer fluoroquinolones 2 hours before or 6 hours after consuming these foods
- Examples of Fluoroquinolones (end in -xacin):
- Ciprofloxacin
- Levofloxacin
- Moxifloxacin
- Macrolide antibiotics (end in -mycin): commonly used to treat community-acquired
pneumonia (MOA: Inhibition of bacterial protein biosynthesis)
- Azithromycin: treats mild pneumonia, more tolerable, may be administered in a short
course
- Clarithromycin: better activity against Haemophilus influenza and Moraxella
catarrhalis
- Erythromycin: can be used during pregnancy.
- First choice for CAP because they provide good coverage for the most likely
organisms that cause the disease
- Considerations: GI upset, drug interactions, give to people under 60, non-smokers
- Monitoring for therapeutic efficacy of antibiotics
- Clinical criteria: fever, respiratory rate, O2, T, as well as mental status and ability to
eat
- Biomarkers: CRP and procalcitonin
- Chest x-ray: to confirm pneumonia has resolved
, - 48-72 hours improvement
- Antibiotics that can cause C Diff.
- Clindamycin: traditional high-risk antibiotic for C. diff
- Cephalosporins (cefdinir and cefpodoxime), fluoroquinolones, penicillins, and
nitrofurantoin
- Fluoroquinolones, macrolides, cephalosporins, clindamycin
Hypothyroidism
- Levothyroxine dosing in special populations
- Pregnancy:
- Thyroid hormone replacement should be prescribed to all pregnant women
because the benefits outweigh the risks
- Pregnant women have an increased metabolic rate → provider should
increase the maintenance dose by 25% to provide adequate coverage
- TSH levels should be monitored q4 weeks
- Levothyroxine is recommended as opposed to combination T3 and T4
medications (which lower maternal TSH levels → fetal neurological
suppression)
- Elderly
- May require smaller doses due to cardiac disruption (e.g. tachycardia,
angina) → require more frequent monitoring
- Drug-Drug interactions
- Bile acid sequestrants, iron salts, and antacids decrease the absorption of po thyroid
preparations
- Estrogens increase TBg → may decrease response to thyroid hormones
- Monitoring for therapeutic efficacy (TSH and T4)
- Thyroid Hormone Synthesis: Decreased T4 stimulates the synthesis of TSH →
TSH stimulates thyroid gland to produce thyroid hormone
- TSH: Primary lab parameter used to measure efficacy of Levothyroxine
- Normal Range: 0.3 to 5 mlU/L
- If elevated → insufficient dosing → hypothyroidism
- If decreased → overdosing → hyperthyroidism
- T4:
- Normal Range: 0.7 to 1.86 ng/dL
- If elevated → hyperthyroidism
- If decreased → hypothyroidism
- TSH level should be evaluated at initiation of therapy and q4-8 weeks until a stable
euthyroid state is reached
