Upgrade to remove ads
Only $35.99/year

Ch 7 Antibiotics

Terms in this set (83)

bactericidal
kill bacteria by cell lysis, DNA breakdown, inhibit DNA replication
Req's fast replication of bacteria to work
Includes: penicillins, cephalosporins, nitroimadazoles, fluroquinolones, (vancomycin?)
bacteriostatic
inhibit bacterial multiplication
Includes: macrolides, lincomycins, tetracyclines
bactericidal with bacteriostatic drugs
they will interfere! don't prescribe together
bacteria needs to be multiplying for bacteriostatic to work
spectrum of activity
Indicates the range of bacteria the antibiotic affects
narrow spectrum
active against some gram positive pathogens
broad spectrum
effective against wider range of bacterial pathogens including gram negative
extended spectrum
act in between narrow and broad spectrum
6 common adverse effects of antibiotic use
Bacterial resistance to antibiotic
Superinfections
GI effects (nausea, vomiting, diarrhea)
Allergic reactions
Photosensitivity
Drug interactions
superinfections
broad-spectrum antibiotic reduces or eliminates the normal bacterial flora of the GI tract, oral cavity, respiratory tract, or vaginal area, which allows for the growth of other organisms like fungi or bacteria
pseudomembranous colitis
due to antibiotic affecting the GI tract through direct irritation or altering the normal GI flora.
Leads to Clostridium difficile (GI upset - diarrhea, cramping)
photosensitivity
more likely to get a sunburn
caused by doxycycline and tetracycline (tetracycline based antibiotics)
misuse resistance
resistance to antibiotics caused by misuse
encourage pts to throw away unused antibiotics, not to take an antibiotic prescribed to someone else, and to take an antibiotic the way it was prescribed
how does dentist determine if antibiotics necessary for oral infection?
based on the knowledge of the bacterium expected to be causing the dental infection
indications for antibiotic in dental practice
Treatment of acute odontogenic/orofacial infections
Prophylaxis against infective endocarditis
Prophylaxis for pts at risk for infection
type of periodontitis in which prescription of systemic antibiotic would be considered
Aggressive periodontitis - when it starts to involve the bone
also, NUG or NUP
antibiotics for chronic periodontitis
Topical antimicrobial agents like Atridox or Arestin are more common
penicillin
1st synthetic antibiotic
bacteriocidal (or bacteriostatic based on dosage)
primarily targets gram +
uses: never topical (more prone to allergic reaction)
Pregnancy cat B, caution during nursing
penicillin action
beta-lactam ring binds to proteins on bacterial cell wall, causes bacteria to leak out
penicillinase
bacteria prod. beta-lactamase (penicillinase)
penicillinase-resistant penicillins created in response: clavulonic acid added, inactivates b-lactamase
penicillin chemical modifications
Penicillinase resistant
Broad-spectrum: amoxicillin
Extended spectrum
penicillin adverse effects
10% pop allergic (if allergic, take cephalosporins)
lowers the effectiveness of birth control
natural penicillin
narrow spectrum
Penicillin VK
drug of choice for dental infections
broad spectrum penicillin
amoxicillin (Amoxil, Trimox)
ampicillin (Omnipen)
beta-lactamase inhibitor
Augmentin: Amoxicillin + clavulonic acid
cephalosporins
4 generations available
limited dental therapeutic usefulness
broad spectrum (but $$$)
Pregnancy cat B, caution with nursing (enters breast milk)
cephalosporins action
bactericidal
action same as penicillin: B-lactam ring
cephalosporins indication
Keflex: cephalexin for joint premed
cephalosporins side effects
may increase warfarin action
10% allergic crossover to penicillin
GI distress, skin rash, superinfections
cephalosporins to know
1st gen: cefadrocil (Duricef), cephaliexin (Keflex)
3rd gen: omnicef (cefdinir)
nitroimadazole prototype
metronidazole (Flagy)
metronidazole in dentistry
tx of NUG & NUP: combo with amoxicillin or Augmentin
Peri implant infections
metronidazole action
specifically on obligate strict anaerobes by inhibiting DNA replication
metronidazole adverse effects
combo w/alcohol - Disulfiram reaction (severe GI rxn)
binds to lithium
warfarin: decrease metabolism, which increases bleeding
Pregnancy cat B
fluoroquinolone prototype
ciprofloxin (cipro)
fluoroquinolone action
bacteriocidal (depending on dose)
inhibit dna replication
fluoroquinolone dental indications
not usually used, except for bacterial sinusitis, chronic periodontitis
fluoroquinolone adverse effects
phototoxicity, convulsions, joint and cartilage dentistry upset GI
Pregnancy cat C
macrolides action
Inhibits multiplication of bacteria by reversibly binding to 50S ribosomal subunit (prevents protein production)
Usually bacteriostatic but can be bactericidal at high doses
macrolides to know
erthryromycin
azithromycin (Z-pak)
erythromycin
1st gen macrolide
most effective against gram +
used if allergic to penicillin
bacteriostatic
limited dental indications (areas of abscess)
erythromycin adverse effects
interacts with P450 liver cytochrome enzyme - causes many drug interactions
reduces metabolism of drugs leading to toxic levels (table 7-3)
Pregnancy cat B
azalides
2nd gen macrolide
more dental indications esp for perio b/c concentrates in PMNs (neutrophils, white blood cells)
azalides examples
Azithromycin (Z-pak): does not interact with P45O liver enzymes (preggo B) Clarithromycin (preggo C)
azalides adverse effects
hepatic dysfunction
pseudomembranous colitis
caution for premed with this due to drug interactions
azalides drug interactions
increase blood level of statins, phenytoin, cyclosporin
Antacids decrease level of macrolides
lincomycins
prototype drug
clindamycin
clindamycin action
attack 50S ribosomal subunit
uses: against anaerobic gram + and gram -
clindamycin indications
off label use: for periodontal therapy refractory periodontitis
clindamycin adverse side effects
pseudomembranous colitis
no significant drug-disease interactions
Pregnancy cat B
tetracyclines actions
inhibits 30S ribosomal subunit (to inhibit bacterial growth and multiplication)
tetracycline indications
periodontal therapy: concentrates in GCF (2-4x more than in blood levels)
anticollagenase properties: binds to calcium of dentin (collagenase creates breakdown of collagen)
tetracycline adverse effects
can cause dizziness
stains newly formed teeth
drug interactions: binds with dairy; interferes with oral contraceptives
Pregnancy cat D - do not give to expectant mother up to age 8
tetracyclines to know
Tetracycline HCl (Sumycin)
Doxycycline
Doxycycline HCl (Vibramyin, Doryx)
Minocycline (Arestin & Atridox)
enzyme suppression therapy
inhibit production of collagenase
use doxycycline 20 mg for enzyme suppression
subantimicrobial dose
low dose that doesn't produce bacteriostatic property
sulfonamides
inhibits synthesis of folic acid
used for recurrent UTI
declined in use (highly allergic - sulfa drug)
sulfonamides adverse effects
GI irritation, skin rashes, photosensitivity, increased warfarin effect
highly allergic
Pregnancy cat C
vancomycin
irreversibly binds to cell wall similar to B-lactams (so bacteriocidal ?)
active again C. difficile assoc with pseudomembranous colitis
strongest antibiotic we have to kill bacteria
vancomycin active effects
chills, fever, nausea, "red man syndrome" - phototoxicity
Pregnancy cat B
doxycycline adverse affect
photosensitivity - avoid sun exposure
infective endocarditis
Inflammation of endothelium that lines heart and cardiac valves caused by bacteria that are normally present in the body.
Most commonly damages mitral valve.
Can occur after an invasive dental procedure.
bacteria tagets valves b/c
avasculature, so allows bacteria to hide from immune system
conditions for prophylaxis antibiotics
1. artificial heart valves
2. history of infective endocarditis
3. certain serious, congenital heart conditions
4. cardiac transplant that develops a problem in a heart valve
premed regimen
to be taken 30-60 mins before procedure
oral: amoxicillin 2g- adults, 50 mg/kg children
if allergic, oral: clindamyacin
premed regimen for joint replacement
refer to medical consult!
standard: cephalexin (or amoxicillin) 2 g po 1 hr before
antimicrobial mouthrinses:
first generation agents
low therapeutic value and low substantivity (ability of compound to stick around
includes: Phenolic compounds (listerine), Cetylpyridiunium (scope), Oxygenating agents (Glyoxide) - to kill anaerobic bacteria
antimicrobial mouthrinses:
second generation agents
Chlorhexidine gluconate 0.12% only one (Peridex, Periogard)
Has high substantivity (positively charged molecule binds to neg charged bacteria cell well, helps lyse them. calcium in dentin and fluoride also neg charged)
Need to wait 30 mins before giving F2 varnish (to avoid rinse and fluoride binding to each other and cancelling out)
controlled-release antimicrobial drugs
Arestin (microspheres of minocycline HCl)
Atridox (10% doxycycline hyclate)
PerioChip (2.5 mg chlorhexidine gluconate)
PPD
purified protein derivative - not meant to be pathogenic
Provides a marker to determine person's exposure to TB (will also test positive if person has received BCG vaccine against TB)
positive PPD test will cause local swelling & induration
BCG vaccine
not given in US due to questionable efficacy
Used in countries where TB is out of control
Will cause false-positive on PPD test
Chest xray only other way to check for TB
TB symptoms
early symptoms develop 4-6 wks after first contact
ex: night sweats
infectious
considered infectious if one has presence of the live organism = latent category
TB drugs (first-line)
Isoniazid (INH)
Rifampin
Rifapentine
Pyrazinamide (PZA)
Ethambutol (can cause red/green blindness)
Isoniazid (INH)
adverse rxn: hepatitis, B6 deficiency
Riframpin
causes red/orange saliva
induces CYP450 enzymes
latent TB infection treatment
Unresistant strain: Isoniazid for 9 mos
Resistant strain: rifampin 4 mos or combo of rifampin and pyrazinamide for 2 mos
active TB infection treatment
one drug alone should not be used
Four drug regimen: isoniazid, riframpin, pyrazinamide, & ethambutol for min 2 mos, then
Continuous phase with isoniazid & riframpin for 4 mos
TB drugs (second-line)
Cycloserine
Streptomycin
Ciproflaxacin
goal of TB treatment
Cure disease without relapse, prevent death, stop spread, prevent resistant TB strains
Drug therapy is long-term so compliance is an issue with treatment
prophylaxis for latent TB pt
Do a medical consult as needed
Use standard precautions w/pts taking meds for TB as they quickly become non-infectious shortly after drug therapy starts
Minimize creation of aerosols - TB will stay in aerosols for 8 hrs
If see Isoniazid on HH: know pt in latent phase
prophylaxis for active TB pt
DO NOT treat
postpone dental treatment until under control
TB and HIV
same drugs as pt w/o HIV, but at higher risk for resistant TB strain
higher dose of INH and rifampin in continuation phase
children with TB
start treatment immediately, even if in latent phase - start them with 4-drug regimen
rare for children to spread TB
Sets with similar terms