Pharm Block II - Antimicrobials Flashcards by Sam Sarsten

prophylaxis

treating pts who are not yet infected or have not yet developed disease.

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empiric therapy

use of antibiotics to tx an infection before the specific causative organism has been identified w/ lab test

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definitive therapy

use of specific antibiotics based on a previously identified identifying organism

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normal flora

organisms that live symbiotically on or w/in the human hose but rarely cause disease

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colonization

the process of a newly introduced microorganism that successfully competes w/ normal flora

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infection

a disease caused by microorganisms, esp those that release toxins or invade body tissue

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superinfection

a new infection occurring in a pt already having an infection (usually caused by opportunistic microorganisms resistant to the antimicrobial agents used in tx of the first infection)

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contamination

the introduction of pathogens or infectious material into or on normally clean or sterile objects, spaces, or surfaces

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bactericidal

capable of killing bacteria

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bacteriostatic

inhibition or retardation of the growth of bacteria w/out their destruction

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Minimum inhibitory concentration (MIC)

the lowest concentration antibiotic that inhibits bacterial growth

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minimum bactericidal concentration

the lowest concentration of antibiotic that kills 99.9% of bacteria

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Susceptible

Infection caused by organism likely to respond to treatment with this drug at recommended dosages

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Intermediate susceptibility

Antibiotic can be used for tx at high doses (b/c low toxicity or concentrated focus of infection)

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Resistant

Organism not expected to respond to given drug

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Site of infection

Gives clues on bacteria involved and type of drug needed

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penetration & concentration of abx in CSF is a result of

lipid solubility, molecular weight of drug, protein binding of drug

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Severity of infection

Need to decide dosage, route, bacteriostatic vs bacteriocidal depending on severity

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7 things to consider about host characteristics

Immune system (immunocompromised); renal (inappropriate accumulation); liver funciton (drugs may not be properly eliminated); perfusion (preventing distribution); age (young and old); pregnancy (categories - X worst); lactation.

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6 things to consider about antibiotic characteristics

Kinetics (ADME); dynamics (what drug does to body); spectra of activity (another card); cost; interactions; adverse reactions (pt education).

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Spectra of activity

Narrow (acts against single or limited group of microorgs); extended (acts against gram + and -); broad; bactericidal (kill target organism, chosen for critically ill); bacteriostatic (inhibit/delay bacterial growth limitinig spread of infection until immune system can take over)

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Additive combination drug response

The response elicited by combined drugs is equal to the combined responses of the individual drugs if they were taken separately (1+1=2)

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Synergistic combination drug response

The response elicited by combined drugs is greater than the combined response of the individual drugs if they were taken separately (1+1=3) (eg Clavulanic acid with penicillins)

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MOA for aminoglycosides

ribosomal protein synthesis inhibitor – bactericidal

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Coverage for aminoglycosides

Gram negs; gram pos (enterococcus) when used synergistically with B-lactams; not anaerobes

gentamicin, streptomycin, neomycin are examples of which class of antibiotic?

aminoglycosides

Adverse reactions for aminoglycosides

Nephrotoxicity

Coverage for penicillins

Must be able to reach penicillin binding protein; gram pos b/c cell was easily crossed; gram neg if porins permit transmembrane entry; some anaerobes

what are the 2 subclasses within beta-lactams?

- penicillins- cephalosporins

MOA of PCNs

inhibits cell wall synthesis

Adverse reactions for penicillins

Hypersensitivity (up to anaphylaxis)

MOA of cephalosporins

beta lactam binds PCN-binding-proteins and inhibits cell wall synthesis

Name of first generation cephalosporins and coverage

Cefazolin, Cephalexin; (mostly gram pos) strep, MSSA, E coli, Kleb, oral anaerobes; skin infections some respiratory

Name of second generation cephalosporins and coverage

Cefuroxime, Cefoxitin, Cefaclor; (better than first gen with gram neg weaker with gram pos) H flu, Neisseria, Cefoxitin covers B fragilis

Name of third generation cephalosporins and coverage

Ceftriaxone, cefixime, cefotaxime, ceftazidime; (inferior MSSA activity than first gen, but enhanced against gram neg) Drugs of choice for meningitis, ceftazidime covers P aeruginosa, only oral anaerobes; repiratory infections and serious infections

Name of fourth generation cephalosporin and coverage

Cefepime; strep, MSSA, aerobic gram neg (P aeruginosa), oral anaerobes; serious hospital infections

Adverse effects for cephalosporins

Anaphylaxis/hypersensitivity

MOA of nucleoside analogs (antiviral)

inhibits DNA polymerase and incorporates into viral DNA

3 drugs to treat headlice/scabies/crabs

1. lindane (topical use only)2. permethrin3. pyrethrins

clinical use for aminoglycoside antibiotics

Gram - infections (including pseudomonas)

major PCN spectrum of activity

gram +

1st generation cephalosporins (keflex, cefazolin) major spectrum of activity

Gram +

2nd generation cephalosporins (cefuroxime, cefaclor) major spectrum of activity

mediocre coverage for both Gram + and Gram --

3rd generation cephalosporins (ceftriaxone, cefixime) major spectrum of activity

Gram --

4th generation cephalosporins (cefepime) major spectrum of activity

good for both Gram + and Gram -- (typically used for serious, hospitalized infections)

macrolides (erythromycin, clarithromycin, azithromycin) mech of action

inhibition of ribosomal function, therefore, no protein synthesis

macrolide spectrum of activity

Gram +

Macrolide adverse reactions

GI upset, phlebitis

tetracyclines (doxycycline, tetracycline, minocycline) MOA

protein synthesis inhibition(broad spectrum)(adverse rxns: photosensitivity, tooth discoloration in children)

Tetracyclines (doxycycline, tetracycline, minocycline) coverage

Gram pos: strept, MSSA; Gram neg: H flu; Anaerobe: Mosty oral

Tetracylines adverse effects

Photosensitivity, GI upset, tooth discoloration in peds

quinolones (ciprofloxican, norfloxican) MOA

inhibits DNA replication

quinolones spectrum of activity

both Gram + and Gram --; UTI, anthrax, GI infections, atypical resp infections

quinolones adverse effects

GI upset, dizziness, insomnia

sulfa drugs (trimethoprim-sulfamethoxazole) MOA

inhibits synthesis of bacterial dihydrofolic acid(broad spectrum)

Sulfa drugs coverage

Gram + and gram - (most enterobacteria); UTI, GI infections, PCP pneumonia

Sulfa drugs adverse effects

Rash, fever, GI upset

Nucleoside analog examples

acyclovir, vacyclovir, ribavirin

Nucleoside analog MOA

Inhibit viral DNA synthesis

Nucleoside analog coverage

Herpes viruses during acute phase, varicella-zoster, Epstein-Barr

Nucleoside analog adverse effect

Topical - local irritation; PO = headache, N/V/D, renal dysfunciton

Other antiviral examples

amantadine, interferon, oseltamivir

Amantadine MOA

Prevents viral nucleic acid release into host cell

Amantadine coverage

Treats/prevents influenza a

Amantagine adverse effect

Orthostatic hypotension, edema, depression

Interferon MOA

Probably induce host cell enzyme that inhibit viral RNA translation

Interferon coverage

Hep B/C, condylomata acuminata, some cancers.

Interferon adverse effect

Flu-like symptoms, GI disturbance, fatigue

Oseltamivir MOA

Inhibiting viral neuraminidase

Oseltamivir coverage

Influenza A/B

Oseltamivir adverse effect

GI discomfort and nausea

Lidane coverage and route

Scabies, head/crab lice; topical

Permethrin coverage and route

Scabies, head lice; topical

Pyrethins coverage and route

Head, body, pubic lice and eggs; topical

metronidazole indications & adverse effects

ind:treatment of amebic infectionsAE: metallic taste, yeast infections (esp in mouth), dizziness, vertigo; oral

mebendazole coverage and route

wide spectrum use against nematodes; oral

Cross sensitivity risks between beta lactam antibiotics

Although not always the case, beta lactams have a beta lactam ring that IgE antibodies can bind. If a patient shows hypersensitivity to one beta lactam, it is possible they will have the same reaction with a different beta lactam.

Response to antibiotic therapy

Assessed using clinical or laboratory methods, including: reduction in symptoms, dropping WBC count, reduction in consolidation pneumonia, watching for persistent bacteremia.

Reasons for failed treatment

Viral infection, lack of definitive therapy, misidentification of infective agent, failed to exceed/reach MIC/MBC, failure in tx duration, failure to reach infection, drug-drug interactions.

Pharm Block II - Antimicrobials Flashcards

(79 cards)