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Five days of penicillin for strep throat is equal to 10 days
Question clinique
Can strep throat in children and adults be treated with 5 days of oral penicillin?
L’Essentiel
Five days of 800 mg penicillin 4 times a day produced results not worse than (ie, noninferior to) 10 days of 1000 mg penicillin 3 times a day,with shorter symptom duration. This is not the first study to show similar benefits with a shorter duration of oral augmentin/cephalosporin or amoxicillin. 2b
Référence
Plan de l'etude: Randomized controlled trial (single-blinded)
Financement: Government
Cadre: Outpatient (primary care)
Sommaire
The investigators enrolled 317 adults and 105 children (6 years and older) from 17 primary care centers in Sweden. Eligible patients had to have at least 3 Centor criteria and a positive rapid antigen test result for group A streptococcus. Using concealed allocation, patients were randomly assigned to receive either 800 mg penicillin 4 times a day for 5 days or 1000 mg penicillin 3 times a day for 10 days. This was an open-label trial, meaning that both patients and their clinicians were aware of the treatment the patient received. However, the researchers who analyzed the data were masked to treatment until the results were assembled. Clinical cure, defined as complete recovery without major residual symptoms or clinical findings, was assessed 5 days to 7 days after the completion of treatment; that is, on day 10 to day 12 in the 5-day treatment group and on day 15 to day 17 in the 10-day treatment group. This timing of assessment could possibly favor better results with longer treatment. In the per-protocol analysis (patients who completed treatment), cure rates at 5-7 days post treatment were 89.6% in the 5-day group and 93.3% in the 10-day group. Results were similar when using intention-to-treat analysis.Patients receiving the higher daily dose/shorter duration had quicker symptom resolution. Bacterial cure rates were higher with 10 days of treatment but there was no difference in complication rates or new episodes of tonsillitis at the 3-month follow-up. Adverse events such as diarrhea, nausea, or vaginitis were more likely and lasted longer in the 10-day group. The study had a power of 85% to detect a greater than 10% difference between treatments if one existed.
Reviewer
Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine
Tufts University
Boston, MA
Commentaires
This whole thing is based on a false premise
Strep throat gets better no matter what. Adding penicillin to the mix shortens the period of symptoms minimally, (something like 18 hours in my (probably flawed) recollection). The justification for using penicillin (or any other Abx) is to prevent rheumatic fever, (not glomerulonephritis, which happens with or without Abx). Rheumatic fever has, to all intents and purposes, disappeared in most settings. (I searched the hospital records in Halifax for a 5 year period, and there was not a single case of RF. But it still does occur in northern communities.) And the disappearance of RF is not the result of aggressive treatment of the entire population with Abx - it is, (in my opinion - yes this is my own analysis, but I challenge the system to prove me wrong), the result of a change in the antigenic properties of the Strep itself. It no longer elicits the production of an antibody which gets confused, and starts licking the joints and biting the heart of the host. (RF is not a result of an attack to the Strep itself - it is essentially an auto-immune response.)
So, bottom line, with a disease which is inherently self-limiting, and in which the basic justification for treating at all is the avoidance of a rare complication which no longer exists, comparing 10 days' treatment, (a figure which was chosen based on studies in the 1940's which showed efficacy in preventing RF with 10 days' treatment, but not shorter periods), with 5 days, 1 day, or none is going to come up with non-inferiority. The treatment is ineffective for its original intent, because the underlying justification has changed,... and disappeared.
The only reason to treat…
The only reason to treat strep pharyngitis is to prevent rheumatic fever. Does 5 days of treatment work as well as 10 days for this purpose? The answer remains unknown and will remain so, as the incidence of RF is so low that studies can’t be done
What of RF?
A huge study would be needed to know if there is any effect on RF. I understand the above argument re RF changing.
I still meet the odd patient with rheumatic heart disease in the past.
2 cases of Sydenham' s chorea, one 25 years ago and one 5 years ago. The pediatrician on call didnt believe it, but the neurologist confirmed it.
High doses of penicillin
This study seems to use MUCH higher doses that those routinely used in Canadian Practice - Penecillin V 300mg TID. So I'm not sure it's much help in my practice.