Antimicrobials Flashcards
time dependent
Optimal effect when the antibiotic’s concentration remains above the MIC in any one duration of the dosing interval
concentration dependent
Optimal effect when concentrations are appreciably above the MIC for a given organism, up to a specific level
What is AUC?
total exposure / time
Bacteriostatic activity
refers to the inhibition of bacterial growth
Bactericidal activity
refers to killing the bacteria
Gram +
- thicker cell wall (peptidoglycan)
- contains teichoic acid
Gram -
- has periplasmic space
- thinner cell wall (peptidoglycan)
- has an outer membrane
- has endotoxins
Beta-lactam antibiotics
- Inhibit bacterial cell wall synthesis
- Responsible for antimicrobial action
- Bactericidal
- Time-dependent killing
Which medications are in the class Penicillins?
- Penicillin VK
- Amoxicillin
- Dicloxacillin
- Amoxicillin-clavulanate
Penicillin VK
- Veetids®
- Covers mostly gram-positive organisms: Enterococci and Streptococci
- Time dependent
- bactericidal
- Administer around-the-clock to promote less variation in peak and trough serum levels
- Take on an empty stomach 1 hour before or 2 hours after meals
Penicillin VK dosages
- Oral (tablet and solution for reconstitution)
- Children: 25-75 mg/kg/day in divided doses q. 6-8 hours
- Adults: 125-500 mg PO q. 6-8 hours
- an IV exists
Penicillin VK uses and indications
- Pharyngitis
- Otitis media
- Skin and soft tissue infections
- Rheumatic fever
- IV is used for gonorrhea
Penicillin VK adverse effects
- Melanoglossia (blackening of the tongue)
- Mild GI effects
- Nausea, vomiting, diarrhea
Amoxicillin
- Amoxil®
- Gram-positive and some gram-negative coverage
- Time dependent
- bactericidal
- Administer around-the-clock to promote less variation in peak and trough serum levels
- Suspension: Shake well before use; may be mixed with formula, milk, fruit juice, water, ginger ale, or cold drinks; administer dose immediately after mixing
Amoxicillin dosages
- Oral (capsule and solution for reconstitution)
- Children: 25-50 mg/kg/day in divided doses q. 8 hours
- Adults: 250-500 mg PO q. 8-12 hours
Amoxicillin uses and indications
- Pharyngitis
- Lower respiratory tract infections (and URI’s)
- Endocarditis prophylaxis
- ENT/skin and soft tissues infections
- Animal bite
Amoxicillin adverse effects
Nausea, vomiting, and diarrhea
Amoxicillin-clavulanate
- Augmentin®
- Covers many gram-negative and gram positive organisms; Some anaerobic coverage
- Dose adjust in renal dysfunction
- Administer around-the-clock to promote less variation in peak and trough serum levels
- Administer with food to increase absorption and decrease stomach upset
clavulanate
beta lactamase inhibitor
Amoxicillin-clavulanate dosages
- Oral (tablets and solution for reconstitution)
- Adults: 500 mg q. 8-12 hours or 875 mg q. 12 hours or 2 grams q. 12 hours
- Children ( < 40 kg): 20-45 mg/kg/day in divided doses two to three times daily
Amoxicillin-clavulanate uses and indications
- Sinusitis
- Otitis media
- Lower respiratory tract infections
- Community acquired pneumonia
- Urinary tract infection
- Bite wounds
Amoxicillin-clavulanate adverse effects
- Diarrhea
- Nausea, vomiting, and abdominal distress
- Has more GI problems than regular amoxicillin
- Hepatic dysfunction (rare)
Dicloxacillin
- Only covers staphylococcus epidermis & aureus (MSSE and MSSA)
- Administer 1 hour before or 2 hours after meals with at least 120 mL of water (to protect the kidneys)
- Administer around-the-clock to promote less variation in peak and trough serum levels.
- Should not be administered in the supine position or immediately before going to bed
- Drug-drug interaction with warfarin (lower effects of warfarin -> lower INR)
Dicloxacillin dosages
- Oral capsule
- 125-500 mg q. 6 hours
Dicloxacillin uses and indications
- Skin and soft tissue infections
- Bite wounds
- Impetigo
Dicloxacillin adverse effects
- Abdominal pain
- Diarrhea
- Nausea
What do the Penicillins have in common?
- time dependent killing
- bactericidal
- GI effects: nausea, vomiting, diarrhea
Which drugs are in the Cephalosporins class?
- Cephalexin
- Cefaclor
- Ceftriaxone
- Cefepime
Cephalosporins
- Classified by generations: 1st - 4th
- Some cross-sensitivity in patients with penicillin allergy
- NONE OF THEM COVER ENTEROCOCCI (which is a gram +) but more broad spectrum
- also beta lactams
Cephalexin
- Keflex®
- 1st generation cephalosporin
- Covers streptococci and staphylococcus aureus; some gram negative
- Dose adjust with renal impairment
- can take with food if GI distress
- Give around-the-clock to promote less variation in peak and trough serum levels
- Associated with elevated INR
- drug interaction w/ metformin (increases met. levels)
Cephalexin dosages
- Oral (capsule and suspension for reconstitution)
- Adult: 250 -1,000 mg q. 6 hours or 500 mg q. 12 hours (max: 4 g/ day)
- Children: 25-100 mg/kg/day in divided doses q. 6-8 hours (max: 4 g/day)
Cephalexin uses and indications
- Impetigo
- Skin and soft tissue infections
- Pharyngitis
- Urinary tract infection
- Otitis media
Cephalexin adverse effects
- Abdominal pain
- Diarrhea
- Dyspepsia
Cefaclor
- Ceclor®
- 2nd generation cephalosporin
- Covers streptococci and staphylococcus aureus
- Expanded gram negative coverage and Anaerobic coverage
- Dose adjust in renal impairment
- Administer around-the-clock to promote less variation in peak and trough serum levels.
- Administer without regard to meals; shake oral suspension well before using
- Extended release tablets: Do not chew, crush, or split; administer with or within 1 hour of food
Cefaclor dosages
- Oral (capsule, tablet, and suspension for reconstitution)
- Adult: 250-500 mg q. 8 hours (500 mg q. 12 hours for ER)
- Children: 20-40 mg/kg/day divided q. 8-12 hours
Cefaclor uses and indications
- Bronchitis
- Otitis media
Cefaclor adverse effects
- Diarrhea; Use with caution in patients with history of GI diseases
- Increase in transaminases; monitor LFT’s