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Volume 2, Issue 1
February 2008
Antibiotic Commonsense
“An investment in knowledge always pays the best interest.” Benjamin Franklin
Treatment of GABHS Pharyngitis in Children
Hope Barnes Pharm.D.
Group A beta-hemolytic streptococcus (GABHS) is the most
common bacterial cause of acute pharyngitis and accounts for
approximately 15-30% of all pharyngitis cases in children.1 It
generally affects school-aged children (to 15 years), is found
in temporate climates and usually occurs in winter to early
spring.2
Because the signs and symptoms of GABHS and other (often
viral) pharyngitis overlap, a diagnosis of GABHS should not
be based on epidemiological and clinical grounds alone. The
guidelines from the Infectious Disease Society of America
(IDSA) recommend obtaining a rapid antigen detection test
(RADT) or a throat culture to establish diagnosis. Because
some RADTs are less sensitive than throat cultures, a
negative RADT for a child or adolescent should be followed
by a throat culture.2
GABHS pharyngitis is treated to prevent acute rheumatic
fever, and suppurative complications; improve clinical signs
and symptoms; and reduce transmission to close contacts.
Several antibiotics are effective for the treatment of GABHS
pharyngitis. Issues to consider when selecting an antibiotic
include efficacy, safety, spectrum (broad or narrow), cost and
likelihood of compliance to dosing schedule.
While early initiation of antimicrobial therapy results in faster
resolution of signs and symptoms, GABSH pharyngitis is
usually a self-limiting disease and constitutional symptoms
disappear within 3-4 days of onset. Therapy can be
postponed up to 9 days after the onset of symptoms and still
prevent the occurrence of rheumatic fever.2
Penicillin V (PCN) or intramuscular benzathrine penicillin G
remain the treatment of choice because of proven efficacy,
safety, narrow spectrum, and low cost according to guidelines
from the Infectious Disease Society of America (IDSA) and
the American Academy of Pediatrics (AAP).
However, results from some studies demonstrated a 35%
treatment failure in GABHS pharyngitis patients treated with
PCN.3, 6 A number of variables may be responsible for these
failures, including noncompliance. It is easy to understand
how noncompliance could contribute to antibiotic failure when
taking the standard PCN regimen into consideration. PCN is
prescribed three to four times daily for 10 days. A study on
medication compliance, performed in 105 adults receiving
antihypertensive medications, found three times daily dosing
was associated with 30-50% compliance compared with 70-
90% compliance for one to two times daily dosing.4
For patients who are unlikely to complete a full 10 day course
of oral therapy, a one time dose of intramuscular benzathine
penicillin is recommended. Two brands of benzathine
penicillin are available on the market, Bicillin LA and Bicillin
CR. It should be noted that the dosing for Bicillin LA and
Bicillin CR is not equivalent unit for unit.5
Clinical failures have also been reported with benzathine
penicillin which may be related to formulation deficiencies,
incorrect dosing, or the presence of beta-lactamase producing
bacteria.6 GABHS itself does not produce beta-lactamase, an
enzyme capable of deactivating PCN’s antibiotic action.
However, co-infection with bacteria such as, H. influenzae, S.
aureus, M. catarrhalis or beta-lactamase producing oral flora
may be the source contributing to PCN failure.7 If this is the
case, antibiotics resistant to beta-lactamase are a good
treatment option.
Cephalosporins resist degradation by beta-lactamase and are
very effective against co-pathogens if present. Cephalosporin
therapy duration is 10 days, with the exception of cefdinir and
cefpodoxime proxetil which are both approved for a 5-day
course of therapy. Cephalosporins, an excellent alternative
treatment option for GABHS, also have their drawbacks. They
have a broader spectrum than PCN; therefore, when used
routinely have an increased risk for developing resistant
bacteria. They are also more expensive than PCN.
Cephalosporins are not contraindicated in patients with PCN
allergy; but should be used cautiously in patients with
Immediate-hypersensitivity to PCN because cross-reactivity to
cephalosporins may occur in rare cases (<1%).8
Macrolides are the treatment class
of choice for PCN allergic patients
with GABHS pharyngitis, unless
local resistance has been identified.
Macrolides are also broadspectrum and beta-lactamaseresistant antibiotics. Azithromycin is
the most popular antibiotic in this
class because it has fewer side
effects, a short treatment regimen
and simple once daily dosing. It is
also more expensive than PCN and
some of the cephalosporins.
“An investment in knowledge always pays the best interest.” Benjamin Franklin
Antibiotic Commonsense
Treatment of GABSH Pharyngitis in Children (cont.)
Erythromycin is a cheaper drug in this class, but it is
associated with more gastrointestinal side effects and
requires 10 days of therapy. Routine prescribing of
azithromycin for the treatment of GABHS has raised
concern about increasing macrolide resistance. In 20022003 there was a 7% resistance rate of GABHS to
macrolides in the U.S.9 In children who fail macrolide
therapy, a throat culture and susceptibility testing should
be performed to determine if macrolide resistant GABHS is
present.
For children who have multiple GABHS pharyngitis
infections a year, amoxicillin-calvulanate and clindamycin
are the treatment of choice and both have comparable
efficacy in the eradication of GABHS.10, 2 Amoxicillinclavulanate contains a beta-lactamase inhibitor protecting
its antibiotic activity. The most common adverse effect of
amoxicillin-clavulnate is diarrhea, which can lead to diaper
rash in the very young and bathroom issues for children in
school. Clindamycin is useful for patients who have a
severe PCN allergy and failed treatment with a macrolide.
Clindamycin is not for routine use because of the
infrequent but significant side effect of
pseudomembranous colitis.
5.
Taketomo CK, Hodding JH, Kraus CM. Pediatric Dosage
Handbook 11th ed 2004. Lexi-Comp: Hudson, OH. P.928 and
package insert for Bicillin LA and Bicillin CR.
6. Kaplan EL, Johnson DR. Unexplained reduced microbiological
efficacy of intramuscular benzathine penicillin G and of oral
penicillin V in eradication of group A streptococci from children
with acute pharyngitis. Pediatrics. 2001;108:1885.
7. Brook I. Penicillin failure in the treatment of acute and relapsing
tonsillopharyngitis is associated with copathogens and alteration
of microbial balance: a role for cephalosporins. Clin Pediatrics.
May 2007;46s:17-24.
8. Lesher BA. Allergic cross-reactivity among beta-lactam
antibiotics. Pharmacist’s Letter. Dec 2005;21#211206.
9. Richter SS, Heilmann KP, Beekmann SE, Miller NJ, Miller AL, et
al. Macrolide-resistant Streptococcus pyogenes in the United
States, 2002-2003. Clin Infect Dis. Sep 2005;41:599-608.
10. Mahakit P, Vicente JG, Butt DI, Angeli G, Bansal S, et al. Oral
clindamycin 300mg BID compared with oral amoxicillin/clavulanic
acid 1 g BID in the outpatient treatment of acute recurrent
pharyngotonsillitis caused by group A beta-hemolytic
streptococci: an international, multicenter, randomized,
investigator-blinded, prospective trial in patients between the
ages of 12 and 60 years. Clin Ther. Jan 2006;28:99-109.
Oral PCN is still the treatment of choice recommended by
many guidelines for the treatment of GABHS pharyngitis,
despite the increasing failure rate. A number of antibiotics
have been found effective for the eradication of GABHS
however they tend to be broad-spectrum and expensive.
Alternative treatments, however, should be used for
children with compliance issues, allergy, or PCN treatment
failure. Antibiotic selection requires consideration of
efficacy, duration of therapy, frequency of administration,
potential side effects, patient allergy, and cost.
References:
1.
2.
3.
4.
Shulman ST. Acute streptococcal pharyngitis in pediatric
medicine. Pediatric Drug 2003. Suppl 1:13-23.
Bisno AL, Gerber MA, Gwaltney JM, Kaplan EL, Schwartz RH.
Practice guidelines for the diagnosis and management of group
A streptococcal pharyngitis. Clin Infect Dis. 2002
July;35(15):113-125.
Brook I. Failure of penicillin to eradicate group A beta-hemolytic
streptococci tonsillitis: causes and management. J Otolaryngol.
2001Dec:30(6):324-9.
Eisen SA, Miller DK, Woodward RS, Spitznagel E, Przybeck TR.
The effect of prescribed daily dose frequency on patient
medication compliance. Arch Intern Med 1990 Sep:150(9):18814.
Would you like a copy of “What can I do to fight a
cold or sore throat” poster (23 in X 25 in) for your
pharmacy or clinic? Call 253 798-4779.
Tacoma-Pierce County
Health Department
Communicable Diseases
3629 S D St, Tacoma, WA 98418
Contact
Phone:
Fax:
Email:
Lois Lux
253 798-6416
253 798-7666
[email protected]