1. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Pharmacotherapy of Infectious Diseases
A Case-Based Approach
Streptococcal Sore Throat
Anas Bahnassi PhD
Anas Bahnassi 2014
2. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Goals of Therapy
• Provide symptomatic relief.
• Prevent suppurative complications, e.g.
mastoiditis, cervical lymphadentitis.
• Prevent nonsuppurative commplications, e.g.
acute rheumatic fever.
• Prevent spread of group A streptococci to
contacts.
Anas Bahnassi 2014
3. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Investigations
• Culturing group A
streptococci is needed in a
child:
– > 3 year old.
– Acute sore throat.
– Lacks signs of viral URT
infection.
– Has the sore throat
symptoms.
Anas Bahnassi 2014
4. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Investigations
Clinical Diagnosis of Streptococcal Throat
• Adenitis.
• Positive throat cultures.
Although not diagnostic:
• Signs: tender cervical adenopathy, erythematous
pharynx and tonsils, pharyngeal exudate,
excoriated nares, scarlatiniform rash.
• Symptoms: sore throat, pain on swallowing,
headache, abdominal pain, nausea, vomiting, and
feer.
Anas Bahnassi 2014
5. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Laboratory Diagnosis
• Throat culture “Gold Standard” results in 24-48 hrs.
• Repeat cultures are not necessary in asymptomatic
patients.
• Antigen screening of throat secretion is fast (7-70 mins)
but sensetivity (<90%). Too low to rule out
streptococcal infection in children and adolescents.
• If Antigen screening is negative or unavailable:
– Hold antibiotics for 48hrs
– Perform throat culture.
– This procedure does not increase the chance of rheumatic
fever but avoids the unnecessary use of antibiotics.
Anas Bahnassi 2014
6. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Selected Pathogens of Acute Pharyngitis:
• Viruses: (Adenoviruses, cytomegalovirus, Epistein=Barr,
enteroviruses, influenza, herpes simplex virus, and
parainfluenza virus)
• Group A β-hemolytic streptococci (children 15-30%, Adults
5-10%)
• Group C and G β-hemolytic streptococci.
• Neisseria gonorrheae (consider child abuse).
• Mycoplasma pneumoniae.
• Chlamydia trachomatis.
• Chlamydophila pneumoniae.
• Corynebacterium diphtheriae.
• Archanobacterium hemolyticum.
Anas Bahnassi 2014
7. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Management of Acute Pharyngitis
Anas Bahnassi 2014
Acute Sore Throat
Clinical Assessment
Signs and Symptoms of Group A Streptococcal Pharyngitis
Rapid Antigen Test Throat Culture Immediate investigation
not essential, but
diagnosis of streptococcal
pharyngitis not ruled out
+ve -ve +ve -ve
Antibiotic and
Symptomatic Treatment
Symptomatic Treatment
Only
8. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Therapeutic Choices
Nonpharmacologic
• Strict handwashing to prevent spread of
infection.
• Exclude from school or daycare for 24 hours
after antimicrobial therapy is begun.
Anas Bahnassi 2014
9. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Therapeutic Choices
Pharmacologic
• Analgesics:
– APAP.
– Ibuprofen.
– Lozenges, gargles, etc…
• Antibiotics:
– Antibiotic therapy for group A streptococcal pharyngitis can shorten
the course of acute illness and prevent both suppurative
nonsuppurative complications if started early in the illness.
– Penicillin is the DRUG of CHOICE.
– Cephalosporins are effective but should not replace penicillin.
– Amoxicillin suspension is more palatable than penicillin for children.
– Erythromycin can be used for patients with penicillin allergies.
Anas Bahnassi 2014
10. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Cephalo-sporins
Cefadroxil Adults:
1g/day as a single
dose or BID X10d
Hyper-sensitivity
Use if treatment
Anas Bahnassi 2014
with Penicillin fails
$$$
Cefixime Adults and
Children >12yrs
400mg/d X10days
Children 6m-12yrs
8mg/kg/d X10days
Hyper-sensitivity
Use if treatment
with Penicillin fails
Available in
suspension.
$$$$
Cephalexin Adults:
250mg QID X10d
Children:
25-50mg/kg/day
divided QID X10d
Hyper-sensitivity
Use if treatment
with Penicillin fails
Available in
suspension.
$
11. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Cephalo-sporins
Cefprozil Adults and Children
>12yrs
500mg/d X10days
Children 6m-12yrs
15mg/kg/d divided
BID
Hyper-sensitivity
Use if treatment
Anas Bahnassi 2014
with Penicillin fails
Available in
suspension.
$$$$
Cefuroxime Adults and Children
>12yrs
250mg BID X10days
Children 3m-12yrs
20mg/kg/d divided
BIDX10days
Hyper-sensitivity
Use if treatment
with Penicillin fails
Available in
suspension.
Add milk or juice
prior to dose.
$$
12. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Ketolides Telithromycin Adults
800mg/day once
X5days
Diarrhea Use if treatment
Anas Bahnassi 2014
with β-lactam fails
Telithromycin:
Atorvastatin,
Lovastatin,
Simvastatin,
Itraconazole,
Ketoconazole.
Digoxin levels.
Contraindicated
with ergot,
pimozide and
disopyramide.
$$$$
13. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Linco-semides
Clindamycin Adults
600mg/day BID-QID
X10 days
Children
20-30mg/kg/day
Divided TID X10
days
Diarrhea
C.Difficile
Anas Bahnassi 2014
Alternative to
Erythomycin
Maybe used in
symptomatic
patients with
multiple
pharyngitis
Available in
suspension.
$$$$
14. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Macro-lides
Azithromycin Adults
500mg on day 1
then 250 on
days 2-5
Children
12mg/kg/day
X 5 days.
Lower GI
effects
than
Eryth.
Anas Bahnassi 2014
Available in susp.
Less likely to
interact with other
meds.
$$
Clarithromycin Adults
250mg BID
X10d days
Children
15mg/kg/day
Divided Bid X 10
days.
Lower GI
effects
than
Eryth.
Available in susp.
Clarithromycin:
Atorvastatin,
Lovastatin,
Simvastatin,
prednisone,
theophylline.
$$
15. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Macro-lides
Erythromycin Adults
1g/d divided
BID-QID X10d
1hr prior
meals to
prevent
interactions.
Nausea,
vomiting,
epigastric
distress,
diarrhea,
elevated
liver
enzymes,
cholestatic
jaundice.
Anas Bahnassi 2014
Alternative to
penicillin.
Clarithromycin:
Atorvastatin,
Lovastatin,
Simvastatin,
prednisone,
theophylline.
$$
16. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Antibiotic Treatment
Recommendations
Class Drug Dose ADR Comments Cost
Penicillin Amoxicillin 40mg/kg/d
divided BID-TID
X10days
Well
tolerated
Anas Bahnassi 2014
Available in
chewable and
suspension
$$
Penicillin Adults: 330mg
TID or 600mg
BID X 10 days.
Children: 25-
50mg/kg/d
divided BID
Anaphylaxis
GI distress
Diarrhea.
DRUG of Choice $
Amox/Clav Adults: 500mg
BID X10 days
Children:
40mg/kg/d
divided TID
GI distress
Diarrhea.
Maybe used in
symptomatic
patients with
multiple pharyngitis
Available in
suspension.
$$
17. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Therapeutic Tips
• Early institution of antibiotic therapy shortens the duration of fever,
cervical adenitis, pharyngeal infections, and hastens the overall
clinical improvement.
• Early treatment can hasten the return of children to school and
reduce the number of days out of work.
• Since there is no efficient way to differentiate acutely infected child
and carrier of group A streptococci, all systemic patients with
positive culture should be treated.
• Unfortunately Penicillin (Drug of Choice of Acute pharangitis) often
fails to eradicate pharyngeal streptococcal carriage, Some advocate
the use of clindamycin (20mg/kg/d TID X10d max 600mg/d) or the
addition of rifampin (20mg/kg/d TID X10d max 600mg/d) for the
final 4 days of penicillin therapy.
Anas Bahnassi 2014
18. Pharmacotherapy of Infectious Diseases A Case-Based Approach
Pharmacotherapy:
Infectious Diseases:
Anas Bahnassi PhD
abahnassi@gmail.com
http://www.twitter.com/abpharm
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Anas Bahnassi 2014