drug's ability to injure target without injuring neighboring cells

rigid; high osmotic pressure (action of penicillins, cephalosporin)

PABA of folic acid (action of sulfonamides)

folic acid required by all cells; bacterial synthesis vs. dietary intake

protein synthesis function disrupted based on difference in structure (vs mammalian)

inhibits growth of bacteria

causes death of bacteria

major classes:

antibacterial, antifungal, antiviral

initiation of tx prior to culture results

based on clinical evaluation & knowledge of organism

factors affecting drug chioce, administration or dose

host defenses

site of infection

age

previous allergic reaction

genetic factors

surgery - 1 hr prior & 24 hrs after

bacterial endocarditis (congenital or valvular heart disease; prosthetic valves

neutropenia (high risk for infection

UTI (frequent in women)

influenza - antiviral

penicillin G, V or VK

disrupts cell wall in gram-positive bacteria

Effects: bactericidal

AE: allergic reactions (0.4-0.7%) reaction, from rash to anaphylaxis; pain at IM site; neurotoxicity in high doses; cross-sensitivity

DD: Pen G & aminoglycoside; given together for synergisitic effect but not in same IV solution - inactivates aminoglycosides

adjust dose for renal impairment

oxacillin (Bactocill)

"penicillinase-resistant penicillins"

cell wall disruption

altered structure renders drug resistant to inactivation by beta lactamase

Effect: bactericide

AE: minimal (N,D)

amoxicillin (Moxatag)

"broad-spectrum penicillins"

broad-spectrum; cell wall disruption

ineffective against S. aureus

Effect: bactericide

AE: rash; diarrhea

piperacillin/tazobactam (Zosyn)

"extended-spectrum penicllin"

cell wall distruption

Use: primarily P. aeruginosa (w/ aminoglycoside) ineffective against S. aureus

Effect: bactericide

AE: ticarcillin (Ticar) - large doses often required: Na overload - edema (CHF); decreased platelet function (promotes bleeding)

extend spectrum of penicillins

ampicillin + sulbactan (Unasyn)

amoxicillin + clavulanate acid (Augmentin)

ticarcillin + clavulanate acid (Timentin)

piperacillin + tazobactum (Zosyn)

weaken bacterial wall

most widely used group of antibiotics

often resistant to beta-lacamases

low toxicity

cross sensitivy to penicillin allergy (1%)

cefazolin (Ancef), cephalexin (Keflex)

"first generation cephalosporin"

cell wall disruption

Effect: bactericide

AE: allergic reations; thrombophlebitis, disulfram like reaction (N, V w/ ETOH)

cefoxitin (Mefoxin), cefuroxime (Zinacef)

"second generation cephalosporins"

↑ activity against gram-negative bacteria - cell wall disruption; ↑ resistance to beta-lactamases

Use: ineffective against P. aeruginosa

Effect: bactericide

AE: allergic reations; thrombophlebitis, disulfram like reaction (N, V w/ ETOH)

ceftriaxone (Rocephin)

"third generation cephalosporins"

cell wall disruption

Use: reach CSF tx meningitis - in adults & children; ineffective against P. aeruginosa

Effect: bactericide

AE: allergic reaction; thrombophlebitis; disulfram like reaction (N, V w. ETOH)

cefepime (Maxipime)

"fourth generation cephalosporins"

cell wall disruption; CSF penetration

Use: good CNS penetration, P. aeruginosa

Effect: bactericide

AE: allergic reations; thrombophlebitis, disulfram like reaction (N, V w/ ETOH)

imipenem (Primaxin)

"carbapenems"

broadest spectrum; cell wall disruption

Effect: bactericide

AE: GI (N, V, D); hypersensitivity rash pruritis (itching)' rare - sz; suprainfection (infection on top of infection)(4%)

DD: ↓ valproic acid levels ( ↑ sz threshold)

vancomycin (Vancocin)

disrupts cell wall in gram-positive bacteria

Route: IV, PO (poor absorption), PR

Use: serious infections only; MRSA & C. Diff; can be used in pts w/ allergy to penicillin

Effect: bactericide

AE: ototoxicity (hearing loss - can be reversed); thrombophelbitis (irritation of vein @ site of IV); red-man syndrome (red skin, itching, hives, tachycardia, hypotension), renal failure

Trough: ~15-20 mcg/mL, less serious infections 10 mcg/mL

Used as last resort; serious infections

blood levels monitored

telavancin (Vibativ)

inhibits cell wall synthesis and binds to cell wall disrupting membrane function

Use: complicated skin & skin structure infections (MRSA)

AE: taste disturbance, N, V, foamy urine, red-man syndrome, kidney damage (3%), prolong QT interval

DD: others causing renal damage or QT prolongation

fosfomycin (Monural)

cell wall disruption

Route: PO, single-dose therapy

Use: UTI from e. coli or enterococcus faecalis

Effect: bacteriocide

AE: D, HA

tetracycline (Sumycin), doxycycline (Vibramycin)

broad-spectrum; inhibits protein synthesis in RNA

"bacteriostatic protein synthesis inhibitor (BPSI)"

Use: rickettsia; Lyme disease

Effect: bacteriostatic

AE: GI; tooth discoloration (avoid in children < 8); suprainfection (C. diff), candida (overgrowth of drug resistant organism); hepatotoxicity; renal toxicity; photosensitivity

DD: give 1 hr before or 2 hr after chelating metal ions (Ca, Fe, Al, Zn, Mg)

↑ bacterial resistance r/t extensive use; avoid in renal pts; D s/s of suprainfection

erythromycin (Ery-tab)

broad spectrum; inhibits protein synthesis in most gram-positive & some gram-negative bacteria

"BPSI"

Effect: bactreriostatic

AE: GI; QT prolongation & sudden cardiac death, suprainfection, thrombophelbitis, ototoxicity @ high doses

DD: elevates Theo-24, carbamazepine (Tegretol) & warfarin (Coumadin) levels

less N, take w/out regard to meals except extended release (ER) tabs - take w/ meal)

PO, BID dosing

take w/ out regard to meals

IV & PO, once daily doing

clindamycin (Cleocin)

inhibits protein synthesis

"BPSI"

Effect: bacteriostatic

AE: CDAD=C. diff associated diarrhea (bowel suprainfection w/ C. diff - profuse, watery D (mucus & blood)), abd pain, fever, leukocystosis

linezolid (Zyvox)

unlike any other antibiotic

"BPSI"

Use: "VRE"; nosocomial pneumonia caused by S. Aureus including MRSA

Effect: bacteriostatic

AE: GI - N, D; HA, myelosuppression (suppression of blood cell production in the bone marrow [reversible]); neuropathy (eye(reversible) & peripheral (< 5 months - reversible))

DD: inhibitor of MAOI (risk for severe HTN), SSRI (risk for seratonin syndrome)

gentamycin

narrow-spectrum; alters protein synthesis; bacteriocidal from abnormal proteins

"aminoglycoside"

Route: IM, IV (do not mix w/ other PCNs in IV solution)

Use: P. aeruginosa

Effect: bactericide

AE: ototoxicity; nephrotoxicity

Dosing: once daily (except in pregnant women & burn pts - need divided doses)

monitoring peak & trough (blood work)

DD: other ototoxic drugs

tobramycin

"aminoglycoside"

Use: P. aeruginosa

Effect: bactericidal

AE: ototoxic; nephrotoxic, ↑ risk for CDAD

amikacin (Amikin)

broader spectrum against gram-negative bacilli

"aminoglycoside"

Effect: bactericidal

AE: ototoxic; nephrotoxic