Antibiotics Flashcards
who should receive antibiotic prophylaxis?
certain surgical patients (cardiac, peripheral vascular, ortho, GI, hysterectomy), severely neutropenic patients, the patient at risk for bacterial endocarditis, the patient with recurrent UTIs, severe rheumatic endocarditis
PCN: Narrow- spectrum penicillinase sensitive
Pen G, Pen V- Useful for strep spa, Neisseria spa, many anaerobes, spirochete
PCN: Narrow- spectrum penicillinase resistant
Nafcillin, oxacillin, cloxacilin, dicoxacillin- useful for staph aureus
PCN: Broad- spectrum
Ampicillin, amoxillin, bicampicillin- Useful for H. influenzae, E.Coli, P.mirabilis, N. gonorrhoeae, entercocci
PCN- Extended- Spectrum pencillins
carbenicillin indanyl, ticarcillci, mezlocillin, piperacillin- useful for H. Influenzae, E.Coli, P.Mirabilis, N. Gonorrhoeae, entercocci, plus, Pseudomonas, enterobacter spp., bacterioides fragilis, many klebsiella
PCN- Side effects and toxicities
Pain at IM inn site, rare neurotoxicity, reactions to procaine and potassium, allergy in 2-30min is immediate, accelerated is 1-72 hours, late is days to weeks, anaphylactic retains more common than other drugs
Cephalosporins
are beta-lactam antibiotics that bind to PBPs, resistance to cephalosporins occurs due to beta-lactamases which cleave open the drugs. Groups into generations which take into account spectrum of activity, susceptibility, to beta-lactamases, and increasing ability to penetrate the CSF
First generation cephalosporins
Good gram positive coverage
second generation cephalosporins
gram positive coverage and some gram negative coverage
third generation cephalosporins
gram negative aerobes, ceftazidime is effective against pseudomonas
fourth generation cephalosporin
cefipime- broadesr spectrum, good penetration
Side effects and toxicities of cephalosporins
allergy- micropapular rash after several days is the most common manifestation
Increased bleeding tendencies (cefmetazole, cefoperazone, cefotetan), alcohol intolerance
Carbapenems
broad spectrum beta-lactam anx. Include imipenem (most broad), meropenem, ertapenem
Vancomycin
reserved for serious infections- AAPMC (second choice to metronidazole) MRSA, serious infections in the PCN allergic patients. Binds to cell wall synthesis but is not a beta lactam, ototoxicilty at high levels. Other rxn include rashes, thrombophlebilits, no cross- reactivity in the PCN allergic patient
Tetracyclines
tertracycline, oxytetracyline, demeclocycline, methacycline, doxycycline, and minocycline
Therapeutic uses of tetracycline
infection diseases: rickettsia, chlamydia trachomitis, brucellosis, cholera, mycoplasma pneumonia, lyme disease, anthrax, H Pylori. TX of acne- topical and PO. PUD, periodontal disease
Side effects and toxicities of tetracyclines
GI irritation; NVD, esophageal ulceration, Staining of teeth- avoid during pregnancy, avoid form ages 4mos to 8yrs, supra infection; AAPMC, candida, hepatoxicity, renal toxicity, photosensitivity
Macrolides
Erythromycin, clarithromyscin, azithromycin and dirithromycin
erythromycin- Activity, SE, drug interactions
macrolide. has activity against most gram + and some gram -, drug of choice for the PCN allergic for whooping cough and legionnaires disease.
SE: NVD, cholestatic hepatitis (10-20 days after, reversed with d/c of drug) and supra infection
Drug interaction- Cyp450 inhibitor; theophylline, carbamezepine, warfarin- monitor closely. Do not combine with clinda or chloramphenicol
clarithromycin
for soft tissue and skin infections, H pylorim respiratory tract infections in PCN allergic patients