Transcript slides#21 - DENTISTRY 2012

Antibiotic Use In Dentistry
Dr. Soukaina Ryalat
Writing Prescriptions
Rx: Drug Name (can be generic) Unit Dose
(ex: Pen V-K 500 mg, Elixer, Sol’n)
Disp: # of pills, milliliters (ml)
Sig: Directions for use. q24h (daily), q12h, q8h, q6h, q4h,
prn pain, till gone
Refills__
Signature
DEA #
 Most antibiotics have 2 names, the trade or
brand name, created by the drug company
that manufactures the drug, and a generic
name, based on the antibiotic's chemical
structure or chemical class. Trade names
such as Keflex and Zithromax are
capitalized. Generics such as cephalexin
and azithromycin are not capitalized.
Barry Brainfart Dental Clinic 666 Bite Me Ln
Crossbyte Falls, MN Ph: 555-YOU-HURT
Pt. Name:

Rx:

Disp:

Sig:
Refill____
Address:
DOB:
Date:
Barry Brainfart, DDS
DEA:______________________
 Antibiotics have 2 names :
 Generic name ; based on chemical constituents of
the drug & it is not capitalized .
 Trade name ; created by the drug company & it is
capitalized.
 Examples :
 generic name: cefalexin ( 1st generation
cephalosporin)
 Trade name: Sporidex produced by Ranbaxy
company & Keflex by Lilly company.
Antibiotic Strategies
 Cardinal Rules: 1) Use the right drug.
2) Use the right dose. 3) Use the correct
dosing schedule. 4) Correct duration.
 Use a loading dose to rapidly achieve
therapeutic blood levels.
 Avoid combinations of bacteriostatic and
bacteriocidal drugs.




Rules for prescribing antibiotics:
Use the write drug
Use the write dose
Use the correct dose schedule & correct duration.
 Most odontogenic infections are caused by mixed
organisms .
 When we prescribe antibiotic we have to reach MIC ( Minimum
Inhibitory Concentration: is the smallest concentration of an
antimicrobial needed to stop bacterial growth ).
 Most of the drugs take their action within 2-3 days but we give an extra
2 days to make sure that the patient has taken the drug the right way &
the desired effect has been achieved ( patient compliance).
Considerations




Gram Positive?
Gram Negative?
Mixed Infection?
Anaerobes?
Broad Spectrum Antibiotics
 Affects both Gram + and Gram – bacteria,
better for mixed infections.
 Examples: Amoxicillin, Ampicillin
Common Pathogens
Necrotic pulp and apical
abscesses
Obligate anaerobic bacteria
Gram negative rods
Prevotella & porphyomonas spp.
Fusobacterium spp.
Campylobacter rectus
Gram positive rods
Eubacterium spp.
Actinomycetes spp.
 Gram positive cocci
– Peptostreptococcus spp.
– Facultative anaerobic bacteria
 Gram positive cocci
– Strep and Entercoccus spp.
Common Pathogens
 Periodontal Diseases
Gingivitis
Fuso, strep, & actinomycetes
Bacteroides, porphyomonas,
peptostreptococcus & prevotella
Acute necrotizing ulcerative gingivitis
Spirochetes, prevotella, fuso
Localized juvenile periodontitis
Actinobacillus
Antibiotic Resistance
 Three main types
– Chromosome mediated
 Spontaneous mutations
 Non-major form of drug resistance
 Rarely lead to complete resistance
– Plasmid mediated (conjugation)
 VERY important from clinical standpoint
 Mostly gram negs
 Mediate resistance to multiple drugs
 High transfer rate from cell to cell
– Transposon (transduction and transformation)
 Phage mediated
 Clinically important for Gram +
Antibiotic Choices
ß-Lactams
 Natural penicillins
– Pen V and Pen G
 MOA (mechanism of action): Inhibit cell wall
synthesis
 Dose: 250-500 mg qid x 7-10 days
 Contraindications:
– Allergies
– Poor renal fxn
 Adverse events: GI upset
 Drug interactions: oral contraceptives
 Pregnancy category B
ß-Lactams
 Natural penicillins
– Pen V and Pen G
 Bactericidal
 Allergic reaction: rare (4 per 100,000)
 Spectrum:
– Strep, staph, enterococcus, neiseria, treponema, listeria
 Resistance:
– Mostly staph (>80%)
ß-Lactams
 Amino-penicillins
– Amoxicillin, ampicillin
 MOA: Inhibit cell wall synthesis
 Dose: 250-500 mg q 8 h x 7-10 days
 Contraindications:
– Allergies
– Poor renal fxn
 Adverse events: GI upset
 Drug interactions: oral contraceptives
 Amoxicillin and clavulanic acid (Augmentin)
ß-Lactams
 Amino-penicillins
– Amoxicillin, ampicillin
 Bactericidal
 “ampicillin” rash (4-10%)
 Spectrum:
– Strep, staph, enterococcus, neiseria, treponema, listeria,
E. coli, proteus, H. Flu, shigella, salmonella
 Resistance:
– Entero, citro, serratia, proteus vulagris, provedincia,
morganella, pseudomonas aeriginosa, acinetobacter
Cephalosporins
 Cephalexin (Keflex)
– MOA: Inhibit cell wall synthesis
– Dose: 250-1000mg q 6 h x 7-10 days
– Contraindications:
 Allergies
 Poor renal fxn
– Adverse events: mild GI
– Drug interactions: probenecid
– Pregnancy category B
Cephalosporins
 Cephalexin (Keflex)
– Bactericidal
– Spectrum:
 Gram +
– Resistance:
 Methicillin resistant gram +
– Low cross sensitivity with PCN
 Cephalosporins, 1st generation Cefadroxil
DURICEF
Cefazolin
ANCEFKEFZOL
Cephalexin
KEFLEX
Mainly skin and soft-tissue infections
 Gastrointestinal upset and diarrhea
NauseaAllergic reactions
 Cephalosporins, 2nd generation CefaclorCefoxitin
MEFOXIN
Cefprozil
CEFZIL
Cefuroxime
CEFTINZINACEF
Loracarbef
 Some respiratory infections and, for cefoxitin
MEFOXIN
, abdominal infectionss
 Gastrointestinal upset and diarrheaNauseaAllergic
reactions
 Cephalosporins, 3rd generation Cefixime
SUPRAX
Cefdinir
OMNICEF
Cefditoren
SPECTRACEF
CefoperazoneCefotaxime
CLAFORAN
Cefpodoxime
VANTIN
 Ceftazidime
FORTAZTAZICEF
Ceftibuten
CEDAX
Ceftizoxime
CEFIZOX
Ceftriaxone
ROCEPHIN
3d generation
 Given by mouth: Broad coverage of
many bacteria for people with mild-tomoderate infections, including skin and
soft-tissue infections.
 Given by injection: Serious infections
(such as meningitis or infections
acquired in a hospital)
 Cephalosporins, 4th generation
Cefepime
MAXIPIME
Serious infections (including
Pseudomonas infections), particularly in
people with a weakened immune system
and infections due to susceptible
bacteria resistant to other antibiotics
 Cephalosporins, 5th generation
Ceftobiprole
 Complicated skin infections, including
foot infections in people with diabetes,
due to susceptible bacteria, such as
Escherichia coli, Pseudomonas
aeruginosa, and methicillin-resistant
Staphylococcus aureus (MRSA)
Lincosamides
 Clindamycin (Cleocin)
– MOA: binds to the 50S ribosomal subunit and inhibits
protein synthesis
– Dose: 100-450mg q 6 h x 7-10 days
– Precautions:
 Poor hepatic fxn
– Adverse events: GI upset, pseudomembraneous
colitis
– Drug interactions: neuromuscular blocking agents
– Pregnancy category B
Lincosamides
 Clindamycin
– Bactericidal or static depending on
concentration
– Spectrum:
 Gram +, anaerobes, parasites
– Resistance
 Enteroccocus
*Clostridium diff. pseudomembranous colitis!!
Macrolides
 Azithromycin (Zithromax), clarithromycin (Biaxin)
– MOA: bind to the 23S rRNA in the 50S subunit ribosome
– Dose: 250-500 mg/day x 5-10 days
– Precautions :
 Poor hepatic fxn
– Adverse effects: GI
– Drug interactions: Cytochrome P-450
– Pregnancy category B
Macrolides
 Azithromycin, clarithromycin
– Bactericidal
– Spectrum:
 Gram +, gram -, anaerobes
– Resistance:
 B. fragilis, and strep pneumo
Tetracyclines
 Doxycycline (Vibramycin)
– MOA: inhibit protein synthesis by preventing aminoacyl
transfer RNA from entering the acceptor sites on the
ribosome
– Dose: 100mg qd-bid x 7-14 days
– Contraindications:
 Food
 pregnancy
– Adverse events: GI
– Drug interactions: anti-epileptics
– Pregnancy category D
Tetracyclines
 Doxycycline
– Bacteriostatic
– Spectrum:
 Broad, Gram +, -, anaerobes, aerobes, and
spirochetes
– Resistance:
 Widespread, cross resistance
– PHOTO SENSITIVITY!!!
Nitroimidazoles
 Metronidazole (Flagyl)
– MOA: reduced intermediate interacts and
breaks the bacterial or parasitic DNA
– Dose: 250-1000 mg q 6-8 h x 7-10 days
– Precautions : poor hepatic fxn
– Adverse events: GI upset.
– Drug interactions: warfarin, Li+
– Pregnancy category D
Nitroimidazoles
 Metronidazole
– Bactericidal
– Spectrum:
 Gram - anaerobes
– Resistance:
 Rare, H. Pylori?
– Unpleasant metallic taste
Fluoroquinolones
 Ciprofloxacin (Cipro)
– MOA: Inhibition of DNA gyrase, and Topo II
– Dose: 250-500 mg qd x 7-10 days
– Contraindications: <18 yrs old, pregnancy
– Adverse events: spontaneous tendon rupture
– Drug interactions: probenacid, warfarin
– Pregnancy category C
Fluoroquinolones
 Ciprofloxacin
– Bactericidal
– Spectrum:
 Very broad except B. frag
– Resistance:
 MRSA, MRSE
Antifungals
 Nystatin
– MOA: inhibit cell wall synthesis
– Dose: 5 ml swish and swallow q 4 h x 10-14 d
– GI upset
– Drug interactions: minor
– Pregnancy category C
Antifungals
 Clotrimazole (Mycelex), ketoconazole
(Nizoral), fluconazole (Diflucan)
– MOA: inhibit cell wall synthesis
– Dose: 200-800 mg qd x up to 12 months
– GI upset
– Drug interactions: major p-450 enzyme inhibitor,
interactions with many drugs
– Pregnancy category C
ADA Regulations
Antibiotic prophylaxis is NOT
recommended for dental patients
with plates, pins, or screws, nor is
it routinely recommended for
MOST dental patients with TOTAL
JOINT REPLACEMENTS.
 Prophylaxis recommended
– Total joint replacement within the last two years
AND:
 Compromised immune system OR
 Type 1 DM OR
 Previous prosthetic joint infections OR
 Malnourishment OR
 Hemophilia
 Prophylaxis antibiotic recommendations
– No specific regimen recommended
– Keflex is often the first drug of choice
Legal Considerations
 The dentist may not be aware of the
patient’s medical condition.
 Physician may not be aware of the advisory
statements or of the dental procedure to be
performed.
 Documentation.
 Pharmaceutical pregnancy categories :
 Category A :
 Adequate & well controlled studies on both humans &
animals have failed to demonstrate risk to the fetus.
 Category B :
 Animal reproduction studies have failed to demonstrate a
risk to the fetus & there are no adequate & well controlled
studies in pregnant women.
 Category C :
 Animal reproduction studies have shown an adverse effect
on the fetus & there are no adequate & well controlled
studies in humans, but potential benefits may warrant use
of the drug in pregnant women despite potential risk.
In Summary….
Principles of Antibiotic Therapy
 Therapeutic effectiveness
– Clinical indications
 Pharmcodynamics, pharmacokinetics
– Age and extent of infection
Patient factors
 Age, allergies, compliance, pregnancy risk
 Patient function
– Renal, hepatic, immunosuppresion, route
applicability
 Cost
– Brand name, length of course, alternatives?
Cost
Drug Name
Cost of Therapy $ (~10 Days) Generic if Available
Pen VK
6.81
Amoxicillin
8.41
Ampicillin
12.45
Cephalexin
15.65
Clindamycin
38.45
Azithromycin
41.52
Clarithromycin
74.45
Augmentin
76.82
Doxycycline
5.15
Metronidazole
9.65
Ciprofloxacin
76.65
Nystatin
9.86
Clotrimazole
97.05
Ketoconazole
30.69
Fluconazole
116.25
Dental Infection
Acute—Rapid growth
< 3 days
Chronic > 3 days
Pen VK 500mg q6h or
Amox 500mg q8h or
Cephalosporin
Think Anaerobes
Add Metronidazole 250-500mg
To PCN, Amox, or Ceph
Allergic to PCN
Clindamycin 300mg q8h
Clindamycin 300mg q8h or
Cephalosporin (check allergic Rxn) or
Azith or Clarithromycin