Principles of Antimicrobial Use Flashcards
Bactericidal vs Bacteriostatic
(Hint: 6 vs 4)
Bactericidal:
1. Bacteria Cell Wall Inhibitors
2. Aminoglycosides
3. Fluoroquinolones
4. Cotrimoxazole
5. Polymyxins
6. Lipopeptides
Bacteriostatic:
1. Tetracyclines
2. Macrolides
3. Sulfonamides
4. Trimethoprim
Food-drug interactions (Antibiotics and antifungals)
- Tetracycline
- Fluoroquinolone
- Posaconazole and Itraconazole
Oral administration available
Cell Wall Synthesis Inhibitor:
1. Penicillin V
2. Penicillinase Resistant Penicillins (Also Parenteral)
3. Aminopenicillins & Augmentin (Also Parenteral)
4. 1st and 2nd Gen Cephalosporin
Protein Synthesis Inhibitor:
1. Tetracyclines (Doxycycline also parenteral)
2. Neomycin
3. 50S Ribosomal Subunit Inhibitors (Also parenteral)
DNA Synthesis Inhibitor:
1. Fluoroquinolones (Also parenteral)
2. Cotrimoxazole (Also parenteral but oral more common)
Others:
Nitrofurantoin
Metronidazole
Poor CSF penetration
1st and 2nd generation cephalosporins, Aminoglycoside, Macrolide, Clindamycin
Renal Clearance
- Cell Wall Synthesis Inhibitors (Except Ceftriaxone)
- Aminoglycosides (Except Neomycin)
- Others: Tetracycline, ciprofloxacin, nitrofurantoin, cotrimoxazole
Drugs generally safe in pregnancy and lactation
Beta Lactams and Macrolides
Caution drugs during pregnancy
Tetracyclines, fluoroquinolones, cotrimoxazole
Drugs to be avoided in renal impairment
Aminoglycosides, High-dose Vancomycin, Sulfonamides
Drugs to be avoided in hepatic impairment
Anti-TB agents (Pyrazinamide), Amoxicillin-clavulanate
Immunocompromised patients should receive what kind of drugs and what kind of therapy
Bactericidal drugs and Combination therapy
What should be done for severely ill patients when prescribing antibiotics?
Initiate active antibiotics ASAP and use broad spectrum coverage
Poor CSF penetration
1st and 2nd generation cephalosporins, Aminoglycosides, Macrolides, Clindamycin
Drugs used to treat CNS infections
Penicillins, 3rd to 4th generation cephalosporins, Meropenem, Vancomycin
Drugs used for prostatitis
Ciprofloxacin and cotrimoxazole
Concentration-dependent bacterial killing abx
Aminoglycosides, Fluoroquinolones, Metronidazole, Daptomycin
Time-dependent killing abx with no persistent effect
Beta Lactams
Time-dependent abx with persistent effect
Vancomycin, Tetracyclines, 50S Ribosomal Subunit inhibitors
PK-PD targets for concentration-dependent bacterial killing
Optimized Peak/MIC ratio (Cmax = 8-10x MIC)
PK-PD target for time dependent bacterial killing with no persistent effect
Optimize %T > MIC (40-70% of dosing interval above MIC)
PK-PD target for time dependent bacterial killing with persistent effect
Optimize AUC:MIC ratio
Vancomycin - 400 to 600
Fluoroquinolone - >30 (+); >125 (-)
PK-PD target for time dependent bacterial killing with persistent effect
Optimize AUC:MIC ratio
Vancomycin - 400 to 600
Fluoroquinolone - >30 (+); >125 (-)
Abx with Prokinetic effect
Erythromycin
PD interactions causing QTc prolongation
Macrolides, Fluoroquinolones, Azoles
PD interactions causing Nephrotoxicity
Aminoglycosides, Vancomycin, Amphotericin B, Sulfonamides
PD interactions causing myelosuppression
Cotrimoxazole, Linezolid
PD interactions causing photosensitivity
Tetracyclines, Fluoroquinolones, Sulfonamides
PD interactions causing serotonergic syndrome
Linezolid
Antimicrobials with good bioavailability
Fluoroquinolones, metronidazole, Cotrimoxazole, Linezolid
Common antibacterials NOT requiring renal dose adjustment
• Azithromycin
• Cloxacillin
• Ceftriaxone
• Clindamycin
• Doxycycline
• Fusidic acid
• Linezolid
• Metronidazole
• Tigecycline
• Isoniazid
• Rifampicin
Common antibacterials that MAY REQUIRE dose adjustment in hepatic impairment
Ceftriaxone
Clindamycin
Fusidic acid
Metronidazole
Rifampicin
Tigecycline