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Pharmacology: Antiinfectives

Terms in this set (33)

What does selective toxicity imply?
How does selective toxicity occur?
What are some examples of selective toxicity?
-toxic to microbes
-can happen because of differences in the cellular chemistry of mammals and pathogens
-ex. disruption of bacterial protein synthesis, cell wall
-ex. inhibition of an enzyme unique to bacteria
What are narrow-spectrum antibiotics?
Why are the typically preferred?
-active against few species of microorganisms
-typically preferred since it's more selective and contribute less to bacterial resistance
What are broad-spectrum antibiotics?
-active against a wide range of microorganisms
What does bacteriocidal mean?
-drugs are directly lethal to bacteria at clinically available concentrations
What does bacteriostatic mean?
-can slow the growth of bacteria, but do not cause cell death
What are 4 microbial mechanisms of drug resistance?
-decrease concentration of a drug at its site of action
-inactivate a drug
-alter structure of drug target molecules
-produce a drug antagonist
What are 2 microbial mechanisms of acquired resistance?
-spontaneous mutation (random changes to DNA)
-conjugation (DNA transfer between bacteria)
How does antibiotic use promote resistance?
What kind of antibiotics promote resistance most?
-antibiotics (especially broad-spectrum) create environments that are favorable for resistant microbes to grow
What are HAIs?
What is another term for HAI?
-hospital acquired infections
-occur since antiinfectives are used in hospitals very frequently
-also called nosocomial infections
What is a superinfection?
Why are superinfections difficult to treat?
-new infection that appears during the treatment of a primary infection
-often caused by drug-resistant microbes which are more difficult to treat
How do we select which antibiotics to give?
What are host factors that might cause a drug to be ruled out?
-identify organisms
-determine how sensitive the organism is to drugs
-consider host factors (allergy, inability to penetrate site of infection, genetics, host defenses)
-tldr; match the drug with the bug
What is empiric therapy?
What factors determine which drug is administered?
-antibiotic given before causative organism is identified
-based on clinical evaluation and knowledge of most likely organism
What are some indications for prophylactic antibiotic use?
-surgery
-neutropenia
-bacterial endocarditis
-other indications
What are some misuses of antibiotics?
-treatment of viral infections
-fever of unknown origin
-improper dosage
-absence of bacteriologic information
-omission of surgical drainage
How can we delay the emergence of drug resistance?
-promote proper drug adherence
-reduce demand for antibiotics
-emphasize adherence
What should we monitor throughout the antibiotic therapy?
How often should we monitor someone on antibiotic therapy?
What are clinical indicators that antibiotic therapy is working?
-clinical responses and lab results; serum drug levels
-frequency of monitoring should be increased with severity of infection
-fever reduction, resolution of signs/symptoms related to affected organ
What is the principal adverse effect of penicillins?
What is a key structural component of penicillins?
What is the mechanism of action of penicillins?
How do bacteria resist penicillins?
Which drugs interact with penicillins?
-allergic reaction
-beta lactam ring
-weakens the cell wall of bacteria going through cell division causing cell death, therefore bactericidal
-penicillin may not reach target; some bacterial enzymes break down penicillins
-aminoglycosides, bacteriostatic antibiotics, probnecid
Which medications are included in the beta lactam family?
-cephalosporins
-aztreonam
-imipenem
-meropenem
-ertapenem
What is penicillinase/beta-lactamase?
How do penicillinases/beta-lactamases work?
-enzyme that breaks down penicillin so that it cannot kill the bacteria
-destroy the beta-lactam ring, compromising the structure of penicillin
What is Penicillin G usually used for?
How toxic is it compared to other antibiotics?
-numerous gram-positive and some gram-negative bacteria
-least toxic
What characterizes anaphylaxis?
How is anaphylaxis treated?
How can we prevent penicillin-related anaphylaxis?
-laryngeal edema, bronchoconstriction, severe hypotension
-epinephrine, respiratory support
-thorough history, test for allergy before administration
What are the broad-spectrum antibiotics?
What are common adverse effects of broad-spectrum antibiotics?
-amoxicillin, ampicillin
-rash, diarrhea
How much are cephalosporins used in comparison to other antibiotics?
Do cephalosporins have a beta-lactam ring?
Are they bacteriostatic or bactericidal?
How are cephalosporins ususally administered?
How toxic are they?
What is the mechanism of action of cephalosporins?
Which cells are they most active against?
How effective are beta-lactamases at resisting?
Which drugs interact with cephalosporins?
What are some adverse effects?
-most widely used
-yes
-bactericidal
-parentally
-low toxicity
-bind to PBPs, disrupt cell wall synthesis, cause lysis
-actively dividing cells
-first generation stand no chance, third, fourth and fifth generation much more resistant
-probenecid, alcohol, drugs that promote bleeding, calcium (ceftriaxone)
-allergy, bleeding, thrombophlebitis, others
What is the mechanism of action of vancomycin?
What are indications for vancomycin?
How is vancomycin administered?
What are some adverse effects?
Can ototoxicity be reversed?
-inhibits cell wall synthesis
-severe infections, MRSA, Staph epi, C. diff
-IV
-ototoxicity, "Red Man Syndrome", thrombophlebitis, thrombocytopenia, allergy
-sometimes yes, other times no
Are tetracyclines broad-spectrum or narrow spectrum?
What is the mechanism of action of tetracyclines?
What are some indications for tetracyclines?
What kinds of substances impede absorption of tetracyclines?
What are some adverse effects of tetracyclines?
What are examples of tetracycline?
-broad
-inhibits protein synthesis
-infectious disease, acne, PUD, periodontal disease, RA, M. pneumoniae, lyme disease, anthrax, H. pylori
-calcium supplements, milk products, iron supplements, magnesium-containing laxatives, antacids
-GI irritation, staining of teeth/bones, superinfection, hepatotoxicity, renal toxicity, photosensitivity
-tetracycline, doxycycline
What is the mechanism of action of macrolides?
Are they usually bacteriostatic or bacteriocidal?
What are some uses of macrolides?
What are some adverse effects of macrolides?
What are some examples of macrolides?
-inhibits protein synthesis
-bacteriostatic
-whooping cough, acute diphtheria, chlamydial infections, M. pneumoniae, group A strep
-GI effects, prolonged QT interval, superinfections, thrombophlebitis, transient hearing loss
-erythromycin, azithromycin, clarithromycin
What is the mechanism of action of clindamycin?
What kind of bacteria is it most active against?
The infections cannot be located inside the...?
What are some adverse effects?
-inhibits protein synthesis
-anaerobic
-CNS
-CDAD, hepatic toxicity, blood dyscrasias, diarrhea, allergy
Are aminoglycosides broad or narrow spectrum?
Are aminoglycosides bactericidal or bacteriostatic?
Aminoglycosides can cause damage to which organs?
What are adverse effects of aminoglycosides?
How can we treat aminoglycoside toxicity?
When should peak drug levels be sampled?
When should trough levels be sampled?
-narrow
-bactericidal
-ears and kidneys
-nephrotoxicity, ototoxicity, hypersensitivity, neuromuscular blockade, blood dyscrasias
-IV infusion of a calcium
-30 minutes after IM, or after 30 min IV infusion
-depends on dosing schedule
What is gentamicin used for?
What are some adverse effects of gentamicin?
-treat serious infections caused by gram-negative aerobic bacteria
-nephrotoxicity, ototoxicity
Are sulfonamides and trimethoprim broad or narrow spectrum antibiotics?
What is the mechanism of action fo sulfonamides and trimethoprim?
-broad
-inhibiting tetrahydrofolic acid
What is the primary use of sulfonamides?
What are some adverse effects of sulfonamides?
What kind of interactions occur with sulfonamides?
What is the relationship between sulfonamides and resistance?
-UTI
-hypersensitivity reactions (Stevens-Johnson Syndrome). hematologic effects, kernicterus, renal damage from crystalluria
-metabolism-related interactions, cross hypersensitivity
-many species have developed resistance to sulfonamides
What are the primary uses of trimethoprim?
What are adverse effects of trimethoprim?
-acute and uncomplicated UTIs
-hematologic effects, hyperkalemia, not for use during pregnancy and lactation
What are the therapeutic uses of combination sulfonamide/trimethoprim?
What are the adverse effects of combination sulfonamide/trimethoprim?
-UTI, otitis media, bronchitis, shigellosis, pneumonia, pneumocystitis pneumonia, GI infection
-nausea, vomiting, rash, hyperkalemia, Stevens-Johnson syndrome, blood dyscrasias, kernicterus, renal damage d/t crystalluria
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