Flashcards in Exam 2 Antibiotics Deck (34):
Term for antibiotic that INHIBITS bacterial growth
Bacteriostatic (antagonist) - ALL antibiotics are bacteriostatic
Term for antibiotics that can KILL bacteria
Bactericidal (agonst) - not all antibiotics are bactericidal
Narrow vs broad spectrum
Spectrum describes the range of bacteria an antibiotics can treat
Narrow - only effective against a SMALL number of bacteria (Penicillin)
Broad - effective against MANY types of bacteria (Tetracycline)
The oral cavity contains normal flora which are gram + strep or staph. What causes oral/facial infections?
All resident microorganisms which are already in the mouth; any other bacteria found must have been introduced to oral cavity - like trauma
T/F - NEVER combine a bactericidal antibiotic with a bacteriostatic antibiotic in the same person.
T/F -Never give 2 antibiotics to the same person at the same time.
False - antibiotic synergism = 2 antibiotics work together for more positive effect. but usually there is antibiotic antagonism
What is a minimum inhibitory concentration used for?
To determine bactericidal concentration of an antibiotic.
To reach MIC in a human, it may kill them
Therefore, we give less of the antibiotic to get an antibacterial effect
Penicillin's main route of elimination?
Excreted rapidly as an unchanged molecule (70% within first 4 hours)
- 90% via tubular secretion; active transport
Why would you pretreat with probenecid prior to penicillin?
Probenecid (aka Benemid, tx for gout) competes(greater affinity for carrier) with penicillin for active transport mechanisms therefore slowing secretion of penicillin
Which penicillin is first produced, natural, and commercially bactericidal, NARROW spectrum?
Which penicillin is the first semi-synthetic form, NARROW spectrum (G+ cocci), bactericidal?
Which penicillin is acid stable (more uniform absorption) = penicillinase-labile?
Which penicillin do you take orally (not broken down by gastric acid) take 1 hour before or 2 hours after meals to max. serum levels.
Which penicillin is acid-labile: broke down by gastric acid = incomplete and variable absorption also penicillinase-labile (broken down by penicillinase producing bacteria)?
Not effective if taken after meals
Which penicillin is treatment for STDs
What are some adverse reactions for penicillin V?
Nausea, mild diarrhea, oral candidiasis
Allergic reactions : typically delayed, rash erythema, bullous eruptions, angioedema
Which penicillin V form has better bioavailability?
Potassium form of penicillin V - written penicillin V (not VK)
When would you use a penicillinase resistant penicillin?
Only use if the patient has an infection caused by a penicillinase resistant microorganisms. (ex: cloxacililin, dicloxacillin, peperacillin, tazobactam sodium, ticarcillin, clavulante potassium)
Expensive, toxic, and PROMOTES RESISTANT MICROORGANISMS
Which penicillin is acid stable, not penicillinase resistant, LARGER spectrum G-/G+?
Which penicillin has better bioavailability, not penicillinase-resistant. Treats H. influenzae, sinus and inner ear infections?
Amoxicillin (Amoxil) - (less effective than penicillin VK for aerobic G+ cocci, similar for anaerobes)
Which penicillin is mixed with clavulanic acid which increases spectrum?
Augmentin - inhibits penicillinase enzyme = beta lactamase
Used when pts do not respond to penicillin V within 36-48 hours
What are the 4 the most common adverse effects of penicillin?
2. OPPORTUNISTIC infection - oral or vaginal candidiasis
3. Black hair tongue with chronic use
4. Maculopapular rash - toxicity reaction
What are two types of repository penicillin?
1. Procaine penicillin G - allows penicillin to be dissolved in oil
- given IM (deltoid) for slower rate out of oil
-released over 12-24 hour period
2. Benzathine penicillin G (Bicillin)
-therapeutic blood levels last for 3 weeks!
-takes longer to reach therapeutic level but doesnt reach peak level
-Given IM aqueous penicillin G then Bicillin IM (buttocks)
What does Procaine penicillin G treat?
TREATS TREPONEMA PALLIDUM, ANTHRAX
What does Benzathine penicillin G (Bicillin) treat?
Mechanism of action of penicillin?
Beta-lactams blocks bacterial cell wall (peptidoglycan) synthesis by interfering with structural glycopeptides -> lysis causes bacterial cell death
(lethal to dividing bacteria)
3 reasons someone might not respond to penicillin?
1. Pt. compliance
2. Production of penicillinase
3. Bacteria causing infection if outside of the spectrum - use broader spectrum drug
What is penicillinase?
a beta lactamase (enzyme) that breaks down the beta lactam ring of the penicillin molecule. Without an intact beta lactam ring, penicillin is inffective
What antibiotic is highly resistant to penicillinase. acid stable, inhibits bacterial cell wall synthesis, bactericidal, absorbed well through the GI tract, and is active against G+ aerobic, G- (klebsiella).
Cephalosporin (never the first choice for any orofacial infection)
Who is cephalosporin contraindicated for?
Patients who had full blown type 1 (IgE anaphylaxis) to penicillin (cross-sensitive)
What are 3 first generation cephalosporins?
Active against G+ cocci
1. cefazolin (parenteral only)
2. CEPHALEXIN (KEFLEX)
(Most narrow spectrum)
What are 2 second generation cephalosporins?
More active against G- than first generation
1. cefaclor (Raniclor)
2. cefuroxime (Ceftin)
What is 1 third generation cephalosporins?