LAS VEGAS — What's the treatment of choice for group A streptococcal tonsillopharyngitis?
In 2009, attendees at this pediatric update sponsored by the American Academy of Pediatrics California District 9 were advised that cephalexin was the best first-line treatment. But those who returned this year heard a conflicting recommendation – for amoxicillin taken in one dose per day. Both recommendations differ from the AAP Red Book.
“Amoxicillin is my favorite,” said Dr. Christopher J. Harrison, a pediatrician who is an infectious disease specialist at Children's Mercy Hospital in Kansas City, who presented this year.
While the AAP Red Book, Centers for Disease Control and Prevention, and other organizations still recommend penicillin as the first line of treatment, recent studies have shown it to be less effective than amoxicillin, said Dr. Harrison, citing an article that compared the two regimens in 152 children (Pediatrics 1999;103:47-51).
One problem with penicillin is that the generic versions taste bad, he said, so patients are less likely to take the full course. “The taste has always been an issue,” said Dr. Harrison. Amoxicillin tastes better. So he recommends amoxicillin 50 mg/kg up to 1 g, taken once per day – an approach shown to be effective in one study (Arch. Dis. Child. 2008;93:474-8).
The standard recommendation for amoxicillin is 750 mg four times a day, but administering a drug three to four times a day is hard for families, he said. “That's not something that our parents are going to get done.”
So Dr. Harrison prescribes the amoxicillin all in one dose per day. “The single big dose – or twice a day – is actually pharmacokinetically better than what we used to do,” he said. Fewer, larger doses result in a longer period of time in which the serum level of the drug is at a high concentration. The longer time at a higher concentration is helpful in eradicating bacteria that can protect themselves in biofilm, he said.
He also cited studies showing that cephalosporins, such as cephalexin, are more effective than penicillin.
But he agreed with the Red Book recommendation that these drugs should be used as second-line treatments because of the risk that the bacteria might develop resistance to them. He also pointed out that the cephalosporins, while more successful in eradicating the bacteria, have never been shown to directly prevent rheumatic fever.
Asked to comment, Dr. Michael E. Pichichero, a pediatrician who is an infectious disease specialist at the University of Rochester (N.Y.) Medical Center, stuck to the position he articulated at last year's meeting: that cephalexin is the best first-line treatment. He uses two 15-mg doses per kilogram per day.
He cited his own research, including a study to which he contributed published in Clinical Pediatrics (2008;47:549-54), which found that children treated with first-generation cephalosporins are much less likely to experience symptomatic relapses than children treated with amoxicillin, which in turn works better than penicillin.
“Cephalexin tastes good,” he said. “It can be used twice a day. It doesn't kill the normal flora. And it's no more expensive.” The possibility that the use of cephalexin as a first-line treatment might lead to more resistant strains of streptococcus “has never been shown,” he said. “It's hypothetical.”
Dr. Pichichero pointed out that there are reasons to eradicate the bacteria besides preventing rheumatic fever. “We know that treating results in a reduction in contagion,” he said. “And it prevents sequelae like abscesses of the lymph nodes.”
The question of which antibiotic to use was not the only group A strep controversy Dr. Harrison discussed. He also spoke highly of new rapid tests for strep, citing a recent study in Clinical Pediatrics (2010;49:1050-2) that found that several of the new tests had sensitivity and specificity above 95%.
Based on this research, he doesn't think everyone needs to order a throat culture in the case of a negative result with a rapid test. “It's not really a necessary thing, in my personal opinion, for everyone, although it's recommended.”
The exception? In an area with rheumatic fever or some other special cause for concern, the throat culture is still advisable.
Dr. Harrison disclosed that he has had a financial relationship with GlaxoSmithKline Vaccine Group. Dr. Pichichero said that he had no relevant financial disclosures.
Cephalosporins should be used as second-line treatments because of the risk of bacterial resistance.
Source DR. HARRISON