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.
erythromycin absorption, distribution and excretion patterns
Absorbed from upper part of intestine (best if fasted)
Diffuses readily into tissues, including placenta and most body tissues
excreted into the bile, urine, and feces
Identify two alternative macrolide antibiotics
Erythromycin is but non-useful now for dentistry
Clarithromycin
Azithromycin, or Z-pack
The LINCOSAMIDE clindamycin mechanism of action
(interferes with bacterial protein synthesis and inhibits peptide bond formation)
LINCOSAMIDE clindamycin is good for…
orofacial infections in penicillin allergic patients
2 classes of antibiotics that are most often associated with Clostridium difficile infections
Clindamycin and Cephalosporin
Why not take TETRACYLINES with food?
contraindication for TETRACYLINES
Contraindicated in children with developing teeth/bone, pregnant patients
Incorporated into teeth/bone through chelation causing pitting and yellowing
Tell me about doxycycline…
i. Most used one in dentistry
ii. Inhibits collagenase (which breas down CT and bone)
Doxycycline hyclate (Periostat) is a subantimicrobial dose that inhib collagenase but doesn t kill bacteria
iii. Applied subgingivally = Atridox
minocycline
i. Most potent
ii. Photosensitivity!!!!
iii. Stains teeth in adults
iv. Locally applied subgingival microsphere = Arestin
- Travels up dentinal tubules and deposits at DEJ – dose dependent not duration
- Sustained release, powder administration, easy to use and stable for 2y
Tetracyclines (bacteriostatic/antagonist) are contraindicated with…
Penicillin. Because of (bacteriostatic/antagonist) are contraindicated with penicillin/amoxicillin (bactericidal)
Name the major indications for quinolones.
In MEDICAL
i. Community acquired diseases
ii. Respiratory infections
iii. Bronchitis, community-acquired pneumonia
iv. Urinary tract infections
v. Ciprofloxacin (Cipro) is preferred for anthrax but all antibiotics appear to be effective
IN DENTAL
i. Rarely used in dentistry
ii. Used to treat periodontal disease when other agents are not effective
QUINOLONES mechanism of action
i. Targets DNA topoisomerases
ii. Block the action of two bacterial topoisomerases — enzymes that relieve the coils that form in DNA when the helix is being opened in preparation for replication, transcription, or repair.
mechanism of action of metronidazole and its use in dentistry.
Deactivates cysteine-bearing enzymes, as many as 150 separate enzymes are affected
Used to supplement other antibiotics when periodontal condition is not responding
Sister to Cipro, used for h. pylori
Levofloxacin (Levaquin)
Quinolones to know…
Ciprofloxacin (Cipro) *know this one
Levofloxacin (Levaquin) *know this one
Avoid mixing METRONIDAZOLE with…
Alcohol, Disulfram-like reaction (drug used in alcohol rehab to break desire to drink)
Nausea, vomiting, flushing, headache, sweating, tachycardia etc…
diphenhydramine (Benadryl) use in dentistry
Injected drug in office emergency kit for minor/major allergic reactions/anaphylaxis
chlorpheniramine (Chlor-Trimeton) use in dentistry
In dental office emergency kit for allergic reactions and/or anaphylaxis
non-sedating antihistamines to know.
i. loratadine (Claritin) – OTC *
ii. fexofenadine (Allegra)*
iii. desloratadine (Clarinex)*
1. Second generation of loratadine
- Popular OTC antihistamine
- Approved for treatment of all types of allergens (animals, pollens, smoke, dust, etc.)
- Used for perennial and seasonal allergies
- Causes sedation0 but in some cases only for the firs tweek or so of taking it
cetirizine (Zyrtec)*
opular H2 receptor blockers for gastrointestinal use
i. cimetadine (Tagamet)* (worst drug interactions)
ii. famotidine (Pepcid)*
iii. nizatidine (Axid)*
iv. ranitidine (Zantac)* (SAFEST and most recommended in this class fewest drug interactions )
Name three antifungal agents useful against Candida albicans.
a. nystatin (Mycostatin) * know this one
b. clotrimazole (Mycelex) * know this one
c. amphotericin (Amphocin, Fungizone) * know this one
Describe clotrimazole (Mycelex)
i. used when nystatin doesn’t work
ii. topical ONLY (not for systemic)
iii. troche 5x/day, cream 2x day, solution 2x day
iv. Can cause abnormal liver function (so use nystatin first)
v. Good for vaginal yeast infections
Describe amphotericin (Amphocin, Fungizone)
i. PARENTAL! – admin by IV
ii. Most effective drug against deep-seated, recurrent, opportunistic infection
iii. Used for fungal infections associated with HIV
iv. Learn more next year but popular on board exams
xplain the mechanism of action of nystatin (Mycostatin)
Use squeezed out vaginal suppositories
a. Binds to sterols in fungal cell membrane
b. Changes cell wall permeability
c. Fungal cell leakage of cellular contents
d. Stays in GI tract (very little absorption) but washes from mouth – req cocoa butter
i. Comes in many forms (pastilles/troches, oral suspension, ointment/cream, and powders)
1. All require use 4-5 a day!
a. LOW compliance
two reasons why dentists should avoid prescribing the systemic azole antifungal medications for oral fungal infections.
a. Promote resistance of fungal organisms
b. RED FLAG DRUG: Many dangerous drug interactions
c. Hepatotoxic
d. Itraconazole specifically, causes severe cardiovascular side effects; neuropathy
e. THESE ARE:
i. Reserved for systemic severe cases
mechanism of action of antiviral agent acyclovir (Zovirax)
i. Inhibits viral DNA polymerase preferentially, inhibiting viral replication
ii. Drug is incorporated into viral DNA
Anti viral
i. Oral tablet
ii. Used for immunocomp pt
famiciclovir (Famvir)
Anti Viral
i. Cream only for external lipsand face
ii. Not for immunocompromised pt
iii. Small amount applied every 2 hours (lips and face only) for 4 days
iv. Compliance problems with frequency of application
penciclovir (Denavir)= HSV1
HSV2 (originally targeted for genital herpes suppression)
valacyclovir (Valtrex)
HSV1
i. Apply 5 times per day; start at prodrome and continue until lesions have healed
ii. Do not apply inside of mouth or around eyes
iii. Shortens course of the lesion to 5-6 days
iv. Affordable and good for freq breakouts
Docosanol 10% (Abreva)
i. Viroxyn
ii. OTC medication (but professionally dispensed?)
iii. Single dose applicator vial
iv. At prodrome, rub medication into lesion until medication is gone (10 seconds)
v. Stings! Cauterizes lesion… virucidal
1. Removes lipid coating and kills
vi. Shortens course of lesion to 3-4 days
Isopropyl alcoholl/benzalkonium chloride= HSV1
