Module 11 part 1 Quiz Flashcards
Bactericidal
Disrupt cell wall–>lysis
Classes:
1 penicillins
2. Cephalosporins
3. Individual (Vancomycin)
Penicillins
Beta Lactams, contain beta lactam ring
narrow or broad=treat a wide variety
Low toxicity but common cause of allergies
-can be life threatening
-avoid in patients with allergy history
Action: Disruption of cell wall by targeting PCN binding proteins (PCB)–> bacterial water uptake–> rupture, bactericidal
Beta lactamases promote resistance to PCN
Methicillin is resistant to beta lactamases
Methicillin Resistant Staph Aureus
MRSA: gram +
colonizes in nares, and skin of health people
-Infection: soft tissues, abscess, boils cellulitis
Mortality 30-40%
Developed resistance over time
resistant to methicillin, all PCNs, and most cephalosporins
Health care environment and community
Cephalosporins
Beta-Lactam
Broad spectrum
Low toxicity
Action: bind to PCN binding proteins–>dissruption of cell wall synthesis, activation of autolysis
Admin: poor GI absoprtion, IV or IM
Five generations of drugs
-increase activity against gram negative rods and anerobes
-increase resistance to B-lactamases
-increase CSF penetration
Vancomycin
Indication: MRSA, serious infections, C-diff (PO), gram + only, allergy to PCN
Action: inhibits cell wall synthesis–> lysis, No beta Lactam ring
Admin: IV or IM, except for cdiff (PO)
AEs: Nephrotoxicity-dose related, increase with concurrent use of other nephrotoxins, monitor serum trough levels to avoid toxicity
Bacteriostatic Drugs
-Suppress bacterial growth/replication
-Do not eradicate or kill
-2nd line agent
-Inhibit bacterial protein synthesis
E.g. Tetracyclines, Macrolides
Tetracyclines
Broad spectrum abx: gram + and gram -
Prototype: Doxycycline
Action: inhibit protein synthesis affecting RNA
Extensive use=increasing resistance
-first line use limited
-Used for: lyme disease, chlorea, anthrax, typhus, Q fever, topical for acne
Notes: Food/ Ca+ products decrease absorption through GI, Can cause GI upset (take w/ small meal), monitor for superinfection, Contraindicated for this with renal failure
Macrolides
Broad spectrum
-Most gram +, some gram -
Prototype: Erythromycin
Action: Inhibit protein synthesis. Usually bacteriostatic
Indications: diptheria, as a subisitute for penicillin G, chlamydia
Notes: one of the safest, Small risk for QT prolongation, when combined with CYP inhibitor= 5x risk for death
AVOID IN THOSE W/ QT PROLONGATION/CYP INHIBITORS AND CLASS 1A OR III ANTIDYSRYTHMICS
2nd most common infection, affects women> men
UTI
Lower UTI
Cystitis and urethritits
Upper UTI
Pylenephritits
Complicated UTIs
BPH, indwelling foley, calculi, obstruction
Exception to treatment of UTI w. PO abx
Severe pyelonephritis
Acute cystitis
Lower UTI
Affects women of child bearing age
Sx/symp: dysuria, frequency, suprapubic discomfort, pyuria, bacteriuria
Tx options:
1. Short course (preferred 3 days)
2. Single dose
3. Conventional (7 days)
Urinary tract antiseptics
Prototype: Nitrofuratoin
Broad spectrum: active against common urinary pathogens, indicated for acute lower UTI and proph
Actions: concentrations in the urine and damage DNA, bacteriostatic at low concentrations, bacteriocical at high
Caution: proteus, psedomonas, enterobactar, klebsiella 2ndry to high rates of resistance
SEs: GI (minimized w/ taking with meals/milk), hypersensitivity reactions, irreversible neuropathy
Trimethprim/Sulfamethoxazole
Brand name: Bactrim. fixed dose combination
-Class: sulfonamide combo
Actions: Broad spectrum: sulfa is bacteriostatic and inhibits bacterial synthesis of DNA/RNA, concentrates in urine, trimeth may be bactericidal or static
Infection: UTI, ottitis media, bronchitis
Drug-drug: CYP inhibitor, increase effects of warfarin/glyburide and others
Adverse reactions of sulfa abx
Hypersensitivity- mild: rash, fever, photosensitvity
Severe: steven johnson syndrom, blood dyscrasias
Stevens-Johnson Syndrome
Rare, 25% mortality rate
-associated with long/short acting sulfonamides
Sx/Symp: lesions of skin and mucous membraine, fever, malaise, toxemia
Discontinue sulfa drugs if ANY rash develops
Aminoglycosides
Prototype: Gentamtycin
Spectrum: Narrow
indications: serious infections r/t aerobic gram - bacilli (E.coli, Proteus, etc)
Action: Bacteriocidal by interupting bacterial protein synthesis
Admin: not absorpbed from GI. Given IM, IV, topical
AEs: ototoxicity, nephrotoxicity
Post abx effect: drug remins bacteriocidal several hours after levels fall below the minimum bacteriocical concentration
Fluoroquinolones
Prototype: Ciprofloxacin
Spectrum: broad against most gram + and gram - bacteria. can treat most UTI related pathogens (E. coli, klebsiella)
Applications: multiple
Action: Disrupt DNA replication and cell division
Admin: IV or oral
SE: mild: N/V, headache, candida
Ciprofloxacin
Broad spectrum: Gram + and gram -
Action: Inhibits bacterial enzymes required for replication/division
Uses: respiratory infections, bones/joints, skin and soft tissues, UTIs, Enteritits, not great for anerobes
Drug-Drug: absorption decreased by cation containing compounds (antacids/dairy), increase warfarin/theophylline
Ciprofloxacin adverse reactions
Tendonitis & tendon rupture, usually achilles
-in older adults can=confusion, somnolence, psychosis, phototoxicity
-Worsens MG
Metronidazole/Flagyl
Spectrum: Anerobes/protozoans
Class: nitromidazole
Action: taken up by anerobes and converted=damage to helix
Uses: C. diff, bacterioides, H. pylori, proph in surgical procedures
Drug-Drug: absorption decreased with cation containing compounds (antacids/dairy), increase warfarin/therophylline
TB treatment goals
- eliminate infection
- Prevent relapse
- prevent drug resistance
TB drug resistance
Multi drug resistant TB and extensively drug resistant TB
-resistant to isoniazid and rifampin
-XDR TB-also resistant to fluoquroquinolones and a 2nd line agent
Implications: increase risk of death
-$$$$ standard TB cost 18 K compared to 700 K
What causes TB drug resistance
-too short a course
-doses too low
-erratic adherence
-too few drugs
To help prevent TB drug resistance
-MUST ALWAYS TREAT WITH 2 OR MORE DRUGS
TB drug selection
-sensitivity to organism
-immunocpmpetence of host
-first line: rifampin, isoniazid, ethambutol, pyranzinamide
phased therapy
- Elimination of dividing bacilli render sputum non infectious, may take up to 8 weeks, four drug combo
- Continuation phase
-elimination of persistent organisims
-may take up to 18 weeks
-two drug combo: isoniazid and rifampin
Clinical pears of TB treatment
therapy initiated with four drug combo
-if resistance = + more drugs (up to 7)
-Tx of MDR TB: 2 years of meds
-may require surgery tp excise infected tissue
-40-60% mortality
Adherence for TB treatment
-DOT (directly observed therapy)
-intermittent dosing (2-3x week)
Evaluation of clinical response:
-bacteriological eval of sputum
-chest x ray
Isoniazid
Indications: treatment and prph of TB
Action: bacteriocidal: inhibits synthesis of bacterial cell wall
SEs: peripheral neuropathy, heaptotoxicity (increase in advanced age), neuro effects: ataxia/optic neuritis, psychiatric disturbance, pancreatitis
Drug-drug: potent inhibitor of CYP (raise levels of many drugs)
Patient teaching for Isoniazid
-S/s of hepatits
-need monthly eval for these
