Antimicrobials Flashcards
What are some of the adverse reactions seen with antibiotic administration?
Hypersensitivity reactions (anaphylaxis), Direct organ toxicity, Potential for superinfections, Drug-Drug reactions
What is the most common antibiotic given in surgery and what is the dose?
Ancef. 1-2 grams.
What antimicrobials are safe in pregnancy?
Penicillins, Cephalosporins, Erythromycin
Which antimicrobials should you use with caution in pregnancy and why?
Aminoglycosides (ototoxicity to mom and baby) Clindamycin (colitis in mom)
Which antimicrobials are contraindicated in pregnancy and why?
Tetracyline (tooth discoloration in baby)
What are the two antibiotic categories and how are they different? Which is preferred?
Bactericidal: they kill the bacteria
Bacteriostatic: they reversibly inhibit the growth of bacteria
Bactericidal is preferred but many factors may dictate the use of bacteriostatic
What is a criteria for the use of bacteriostatic antibiotics?
The duration of therapy must be sufficient to allow for cellular and humoral defense mechanisms to eradicate the bacteria
Which antibiotics fall under the bacteriostatic category?
Chloramphenicol, Clindamycin, Macrolides, Sulfonamides, Tetracyclines, Trimethoprim
Which antibiotics fall under the bactericidal category?
Penicillins and Cephalosporins, Isoniazid, Metronidazole, Polymyxins, Rifampin, Vancomycin, Aminoglycosides, Bacitracin, Quinolones
What category of antibiotic is PCN and how does it work?
They interfere with synthesis of peptidoglycans (cell wall component of bacteria) They are bactericidal
People are most commonly allergic to which antibiotic?
PCN. 10%
What are some of the allergic reactions from PCN?
Maculopapular rash (delayed) Anaphylaxis (immediate)
PCN has a cross sensitivity with which other type of antibiotic? Why?
Cephalosporins (8%)
They share a common beta-lactam ring
High doses of PCN have an effect on what in the body?
Platelet aggregation
What is the problem with PCN these days?
Many are developing resistance to this class of antibiotics
What category of antibiotic is Cephalosporins and how do they work?
Bactericidal. They bind to penicillin binding proteins. They are resistant to penicillinases, but not Cephalosporinases.
How are Cephalosporins cleared?
Renal excretion
What are some side effects of Cephalosporins?
Hypersensitivity reactions (cross-hypersensitivity with penicillins 1-3%), Superinfections: enterococci, Enterobacter and candida
Which generation of Cephalosporin has the best coverage for Gram Negatives, Strep Pneumoniae, and Gram Positives collectively? First, Second, Third, or Fourth?
Fourth Generation. +++,+++,++ (respectively to bacteria mentioned) But go with first generation if treating just Gram positive (+++)
What category of antibiotic is Vancomycin and how does it work?
Bactericidal (for most gram-positive bacteria.) It inhibits cell wall synthesis by inhibiting peoptidoglycan synthetase.
What are the indications for use of Vancomycin?
MRSA, Endocarditis due to Strep. viridans or enterococci, Patients allergic to B-lactams.
What is Vancomycin usually reserved for?
Typically reserved for Rx of bacterial infections resistant to other antibiotics, or patients with sever hypersensitivity to other indicated antibiotics