Test 2 Flashcards
Identify the main route of elimination of penicillins.
i. 10% via glomerular filtration (passive transfer)
ii. 90% via tubular secretion (active transport)
Explain the rationale for pretreating patients with probenecid prior to administration of penicillin
If probenecid is given before penicillin is given, the penicillin is not excreted as rapidly Elevates the blood level of penicillin 3-4 times;
i. First penicillin produced; natural and available commercially
ii. Indicated for STDs
iii. Bactericidal
iv. Narrow spectrum
v. Acid-labile = broken down by gastric acid vi. Penicillinase-labile = broken down by penicillinase-producing microorganisms
1. 70-80% destroyed by gastric acid
Penicillin G
i. Penicillin G = bond penicillin molecule to procaine molecule so it can dissolve in oil
ii. Repository form, dissolved in oil, given IM
1. Penicillin escapes slowly out of oil over 12-24hrs
iii. Narrow spectrum iv. No GI absorption
v. Penicillinase-labile = broken down by penicillinase-producing microorganisms vi. Indicated for Treponema pallidum and anthrax
Procaine Penicillin G
Given IM (buttocks) after dose of aqueous penicillin, longest lasting, no GI absorption 1. Longer to reach and lower therapeutic level than Penicillin G
Benzathine Penicillin G (Bicillin)
First synthetic
acid stabile Penicillin not broken down by gastric acid
Narrow spectrum
broken down by penicillinase-producing microorganisms
Penicillin V
only used for infections with penicillinase producing bacteria seen in culture
i. Cloxacillin (canadian drug)
ii. Dicloxacillin (canadian drug)
iii. Piperacillin and tazobactam sodium
iv. Ticarcillin and clavulanate potassium
Broad spectrum penicillins
- One of the most commonly prescribed drugs in US
- Better bioavailability than ampicillin
Amoxicillin
- Bactericidal, broad spectrum
2. Acid stable but usually given by injection
Ampicillin
Use if microorg is producing penicillinase or bacteria causing infection is outside narrow
spectrum of kill from penicillin V
Augmentin
most common adverse effects of penicillin
i. Oral candidiasis
ii. Vaginal candidiasis
iii. Black hairy tongue
amoxicillin rash due to toxicity
Maculopapular rash
Augmentin may cause…
Diarrhea
Name two types of repository penicillin
a. Procaine Penicillin G = repository form
b. Benzathine Penicillin G = repository form
mechanism of action of CEPHALOSPORINS
Inhibit bacterial cell wall synthesis similar to penicillin. Results in defective cell walls and cells
become osmotically unstable causing lysis. Rapidly dividing bacteria are most susceptible. Bactericidal.
bacterial spectra CEPHALOSPORINS
first generation is narrower than the second. The higher the generation, the more broad the spectrum of kill.
Patients who are intolerant to penicillins may be intolerant to…
CEPHALOSPORINS
Name the First generation CEPHALOSPORINS (most narrow spectrum) – mostly for gram + cocci
i. Cephalexin (keflex)* know this one
ii. Cefadroxil (duricef) *know this one
iii. Cephradine (velosef) *know this one
Second generation CEPHALOSPORINS
– more active against gram – bact than 1st gen
eg… i. Cefaclor (raniclor)
most frequently observed adverse effects of the macrolide antibiotics.
(erythromycin, azithromycin, clarithromycin).
i. Stomach pain
ii. Nausea/vomiting
iii. Cramping
iv. DIARRHEA
v. Cholestatic jaundice (hepatitis)
vi. HEPATOTOXIC effects
a. Malaise, nausea, vomiting, abdominal colic, fever
mechanism of action of erythromycin.
Inhibits protein synthesis by binding to 50 S ribosomal subunits of sensitive microorganisms.