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Antibiotics from Ridiculously Simple EVMS


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broad spectrum penicillins
penicillinase-resistant penicillins
anti-pseudomonal penicillins
ticarcillin, carbenicillin (carboxypenicillins)

piperacillin, mezlocillin (ureidopenicillins)
beta-lactamase inhibitors
clavulanic acid

(given in combination with penicillins to treat beta-lactamase resistant combination)
first-generation cephalosporins

(exceptions: cefazolin, cefadroxil)
second-generation cephalosporins

(exceptions: cefmetazole, cefonicid, cefprozil, loracabef)
third-generation cephalosporins

(exception: cefixime, cefoperazone, cefpodoxin, cefetamet)
fourth-generation cephalosporins
What are 1st-gen cephalosporins used for?
Used as alternatives to penicillin for staphylococcal and streptococcal infections when penicillin cannot be tolerated (allergy)
What are 2nd-gen cephalosporins used for?
Good coverate against strep. pneumoniae and H. influenzae. Ideal agent against community-acquired bacterial peumonia when don't know what the organism is.

Cefuroxime good for sinusitis and otitis media (often caused by H. influenzae or branhamella catarrhalis).
Which 2nd-gen cephalosporins cover anaerobic bacteria?
What are 3rd-gen cephalosporins used for?
Used for multi-drug resistant aerobic gram-negative organisms that cause nosocomial pneumonia, meningitis, sepsis, and UTIs
What are 4th-gen cephalosporins used for?
Everything 3rd-gen cephalosporins does + gram-positives and pseudomonas aeruginosa
Which cephalosporins are effective against pseudomonas aeruginosa?
ceftazidime, cefoperazone (3rd-gen)
cefepime (4th-gen)
Which drug has the broadest antibacterial activity of any antibiotic known to man?

kills gram-negatives, gram-positives, and anerobes (even pseudomonas aeruginosa and enterococcus)

resistant bacteria: MRSA, some pseudomonas species, and bacteria w/o cell walls (mycoplasma)
What is always given with imipenem to prevent dihydropeptidase in the normal kidney from breaking it down?
Which carbapenem is stable against dihydropeptidase?
Which beta-lactam drug is a monobactam?
What is aztreonam used for?
gram-negative aerobic bacteria only

kills tough, multi-drug resistant, gram-negative bacteria, including pseudomonas aeruginosa

little cross-reactivity w/ beta-lactams, so can be used in penicillin-allergic patients
Which quinolones are effective against pseudomonas?
Which aminoglycosides are effective against pseudomonas?
tobramycin (best)
What types of antibiotics inhibit the function of bacterial ribosome?
chloramphenicol (50S)
clindamycin (50S)
linezolid (50S)
erythromycin (50S)
tetracycline (30S)
aminoglycoside (30S)
Which anti-ribosomal antibiotic cannot be absorbed orally?
Which anti-ribosomal antibiotic has a very wide spectrum of activity?

gram-positive, gram-negative, anaerobic bacteria
What is chloraphenicol used for?
used to treat bacterial meningitis, when the organism is not yet known and the pt. has severe allergies to penicillins, including cephalosporins

DOC for young children and pregnant women who have RMSF (normally treat w/ tetracycline)
Adverse effects of chloraphenicol?
bone marrow depression: dose related - reversible anemia; aplastic anemia - wipes out bone marrow irreversibly

Gray Baby Syndrome - neonates are unable to conjugate chloraphenicol the in liver or excrete it through the kidney -> increased blood levels -> toxicity -> shock, abdominal distention and cyanosis
What is clindamycin used for?
anerobic infections

also used for infections of the female genital tract
What are the adeverse effects of clindamycin?
pseudomembranous colitis

(however, most cases are now caused by penicillin family drugs (amoxicillin) because they are prescribed more frequently)
How is pseudomembranous colitis treated?
metronidazole - DOC

vancomycin - passes through the GI tract w/o being absorbed -> highly concentrated upon reaching the colon (however, not used much b/c reserved for MRSA)
What is linezolid used for?
newer antimicrobial agent used for resistant gram-positive bacteria

(likely will become a last resort for vancomycin resistant enterococcus)
What are the adverse effects of linezolid?
GI upset (nausea, vomiting, diarrhea)
What is erythromycin used for?
DOC for community-acquired pneumonia that does not require hospitalization (strep. pneumoniae, mycoplasma pneumoniae, chlaymydia trachomatis (strain TWAR))

DOC for Legionnaires' disease

used as an alternative to penicillin for strep and staph organisms in penicillin-allergic pts.

gram-positive organism absorb erythromycin 100x better than gran-negative organisms
What are the adverse effects of erythromycin?
one of the safest antibiotics

1) common and dose-dependent abdominal pain resulting from stimulation of intestinal peristalsis

2) rare cholestatic hepatitis
macrolide antibiotics
What is azithromycin used for?
used as an alternative to doxycycline for treatment of (chlamydial) non-gonococcal urethritis

used commonly to treat community acquired pneumonia
What is the flaw of tetracycline?
(not adverse effects)
passes through the intestine w/o being absorbed when chelated

chelates with cations (milk and milk products, aluminum hydroxide, Ca++, Mg++)
How is doxycycline better than tetracycline?
chelates cations poorly

better absorbed with food
What is tetracycline/doxycycline used for?
1) veneral diseases caused by chlamydia trachomatis
2) walking pneumonia caused by mycoplasma pneumoniae (used as an alternative to erythromycin)
3) animal and tick-borne disease caused by Brucella and Rickettsia
4) doxycycline also works wonders for acne
What are the adverse effects of tetracycline/doxycycline?
1) GI irritation (nausea, vomiting, diarrhea)
2) phototoxic dermatitis
3) renal and hepatic toxicity (usually pregnant women)
4) discolored teeth and depressed bone growth (b/c chelates Ca in bones children < 7)

(Do not prescribe to pregnant women b/c baby's teeth will become discolored)
What is the flaw of aminoglycosides?
(not adverse effect)
must diffuse across the cell wall to enter bacterial cell

often used with penicillin, which breaks down this wall to facilitate diffusion
What is aminoglycoside used for?
kills aerobic gram-negative enteric organisms, including pseudomonas aeruginosa
What is the most commonly used aminoglycoside?

combined with penicillins to treat in-hospital infections

(many bacterial strains resistant to this drug)
Which aminoglycoside is has the broadest spectrum?

(good for nosocomial infections that have developed resistance to other drugs)
Which aminoglycoside is too toxic to be given orally?

used topically for skin infections

(very broad spectrum)
Which aminoglycoside doesn't get absorbed?
(stays in the GI tract)

used orally before GI surgery to prevent spilling of organisms during surgury
What are the adverse effects of aminoglycosides?
1) 8th cranial nerve toxicity - vertigo, hearing loss
2) renal toxicity - aminoglycosides are renally cleared and can damage the kidneys
3) neuromuscular blockade - curare-like effect

(these side effects occur only if the dose is very high)
What is spectinomycin used for?
used to treat gonorrhea, caused by N. gonorrhoeae, as an alternative to penicillin and tetracycline/doxycycline, since many strains are resistant to these drugs
Neisseria gonorrhoeae is resistant to what drugs?
What drugs are used to treat neisseria gonorrhoeae?
ceftriaxone (3rd-gen ceph) - give one shot IM in the butt and doxycycline PO for 7 days to get chlamydia trachomatis that coinfects in 50% of cases

quinolones - one dose PO along w/ doxycycline for the chlamydia

spectinomycin - one shot IM in the butt along w/ doxycycline for the chlamydia
first-line anti-TB antibiotics

(in order of frequency of use)
* = can cause liver damage
Which anti-TB antibiotic has a high risk of liver toxicity if used for more than 2 months?
What are the adverse effects of isoniazid?
1) hepatoxicity - alcoholics have increased risk b/c alcohol increases metabolism of INH by liver --> increases risk for developing hepatitis and decreasing therapeutic effect

2) increases urinary excretion and depletion of pyridoxine (vit. B6) which is needed for proper nerve function
What are the adverse effects of rifampin?
hepatitis (less than INH)

induces CYP450 enzyme system --> decreased half-life of other drugs that go this system

body fluids (urine, feces, saliva, sweat, tears) are colored bright red-orange (not harmful)
What drug turns body fluids red-orange?
What is rifaburin used for?
commonly used to treat mycobacterium avium-intracellulare (MAI)

can also be used to treat TB
What are the adverse effects of rifabutin?
induces the CYP450 enzyme system -> decreasing the half-life of other drugs using this system

(induces less than rifampin)
What are the adverse effects of pyrazinamide?
What are the adverse effects of ethambutol?
dose-dependent, reversible, ocular toxicity leading to...
1) decreased visual acuity with loss of central vision (scotomata)
2) color vision loss

(not used in young children b/c they are unable to report vision deterioration)
What are the adverse effects of streptomycin?
1) ototoxicity -vertigo, hearing loss
2) nephrotoxicity
3) neuromuscular blockade - curare-like effect

(avoid in pregnant women -> can cause congenital deafness)
second-line anti-TB antibiotics
para-aminosalicyclic acid
capreomycin sulfate
amikacin (aminoglycoside)

used when multiple antibiotics are needed for the treatment of multi-drug resistant mycobacterium tuberculosis
What drugs are used to treat leprosy?
What is rifampin used for?
used to treat TB and leprosy
What anti-leprosy drug deposits in the skin and conjunctiva, turning these tissues red?
What is thalidomide used for?
DOC for pts. w/ Type 2 Leprosy Reaction

(this is the only use condoned in the U.S. b/c it is a potent teratogen)
What is the predecessor of fluoroquinolone?
nalidixic acid
What are the adverse effects of fluoroquinolones?
1) GI irritability (nausea, vomiting, belly pain, diarrhea)

2) damages cartilage in animals -> thus avoid usage in children b/c they have more cartilage

3) Achilles tendonitis and tendon rupture

4) CNS side effects (headache, restlessness, insomnia)
What are fluoroquinolones used for?
gram-negative infections

1) multi-resistant pseudomonas aeruginosa (used in CF patients colonized w/ this)

2) enterobacteriaceae (E. coli, Salmonella, Shigella, Campylobacter), except anaerobes (can be used to prevent traveler's diarrhea)

3) complicated UTIs, prostatitis, epididymitis

4) gram-negative facultative intracellular organisms (Legionella, Brucella, Salmonella, Mycobacterium)

5) chronic osteomyelitis cause by gram-positive staph. aureus
What are the adverse effects of trovafloxacin?

(b/c of liver toxicity, FDA advised it should be reserved for treatment only in pts. that meet certain criteria)
What is vancomycin used for?
can be used for all gram-positive bacteria, including MRSA, enterococcus, multi-drug resistant staph. epidermidis

not used for many infections b/c it is reserved for MRSA
What are the adverse effects of vancomycin?
Red-man Syndrome
nephrotoxicity (older prep only)
What drug causes Red-man Syndrome?
antimetabolite antibiotics
What are the adverse effects of sulfamethoxazole/trimethoprim?
rare in persons w/o AIDS

skin rashes

increases warfarin levels in pts. taking warfarin blood thinner
What is trimethroprim/sulfamethoxazole used for?
1) respiratory tree - covers strep. pneumoniae, H. influenzae that cause otitis media, sinusitis, bronchitis, pneumonia

2) GI tract - covers Shigella, Salmonella, and E. coli that cause diarrhea

3) GU tract - covers Enterics that cause UTIs, prostatitis, urethritis

4) AIDS - covers PCP

5) others - toxoplasma gondii, isospora belli

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