Sore Throat in Primary Care - a Comparison of Phenoxymethylpenicillin and no Antibiotic Treatment

Study Overview
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Brief Summary
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Sore throat is the second most common cause of antibiotic prescribing in primary care in Sweden. Guidelines for sore throat focus on identifying people with sore throat where there are 3 and 4 specified criteria and where near patient tests identify group A streptococci (GAS). In these cases, phenoxymethylpenicillin is recommended. Studies that have identified microorganisms in sore throat show that there are other bacteria and viruses than GAS, that give similar symptoms and that sometimes no microorganism is trapped despite pronounced symptoms. In recent years, a bacterium F. necrophorum has been identified, which is found in increased incidence of sore throat, but it is also found in healthy individuals. In clinical practice, many patients are treated with penicillin even if GAS is not captured. This may be because the doctor perceives the patient as sick or because other bacteria are not caught with a near patient test which causes the doctor to treat anyway. The specific aims are to in patients with GAS-negative sore throat and 3 and 4 criteria, aged 15 years and older in primary care, study whether phenoxymethylpenicillin treatment shortens the duration of the disease, reduces the symptom intensity and sickness absence, and investigates the importance of other microorganisms than GAS in sore throat. The study is a randomized controlled trial in which patients with sore throat are randomized to phenoxymethylpenicillin 3 times daily for 10 days or to no antibiotic therapy. There will also be and a reference group with severe (Centor score 3-4), GAS-positive acute tonsillitis. Blood samples for inflammatory and immunological response to infections are taken. Throat samples for culture of F. necrophorum and streptococcal groups C and G, as well as polymerase chain reaction (PCR) analysis for bacteria and viruses are also taken at inclusion and at follow-up. The outcome will be followed in a patient diary for 10 days and at a return visit after 18-24 days where the clinical outcome is asked for and where the blood- and throat samples are repeated. Follow-up will also takes place via e-mail after 1 and 3 months.

Official Title
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A Randomized Controlled Clinical Trial of Streptococcus Group A-negative Acute Tonsillitis in Primary Health Care - a Comparison of Phenoxymethylpenicillin and no Antibiotic Treatment

Conditions
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Sore Throat, Tonsillitis

Intervention / Treatment
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* Drug: Phenoxymethylpenicillin
* Other: No antibiotic treatment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ' Centor score 3-4: absence of cough, anamnestic fever (temperature >38.5°C), tender cervical lymphadenitis, and tonsillar exudates (one or both tonsils) Duration of symptoms < 8 days Rapid antigen detection test for GAS taken and negative Willing and able to give informed consent. Subjects under 18 years of age must in addition have the consent from both parents/caretakers Exclusion Criteria: Ongoing antibiotic treatment Known or suspected allergies to phenoxymethylpenicillin Suspicion of peritonsillar abscess or indication for admittance.

Ages Eligible for Study
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Minimum Age: 15 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Phenoxymethylpenicillin group<br>Patients randomized to oral phenoxymethylpenicillin 1000 mg three times daily for ten days | Drug: Phenoxymethylpenicillin<br>* tablet PcV 1000 mg x 3 for 10 days<br>* Other names: Penicillin V (PcV);|
| Experimental: No antibiotic treatment group<br>Patients randomized to no antibiotic treatment | Other: No antibiotic treatment<br>* No prescription of antibiotics<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in number of days from inclusion to resolution of symptoms | Differences between the randomized groups. Symptom resolution is defined as the first day the item sore throat and difficulty swallowing is scored less than moderately bad | 10 days after inclusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportions of patients with symptom resolution at each of the days 2 through 10. |  | up to 10 days after inclusion | 
| The number of days from inclusion to symptom resolution of the individual items of sore throat symptoms. |  | 10 days after inclusion | 
| Differences in number of days from inclusion to the day the patient can put up with the pain. |  | up to 10 days after inclusion | 
| The possible change in the self-reported items of symptoms on the rating scale for each of the days 2 through 10 and describe the break through day for improvement | The rating is on a 7-point Likert scale 0=no symptoms, 1= very little, 2=slight, 3=moderately bad, 4=bad, 5=very bad, 6=as bad as it could be. | up to between 10 days after inclusion | 
| The number of days the patient needs to stay at home from work/school |  | 10 days after inclusion | 
| Proportion of patients with future episodes of sore throat |  | 30 days and 3 months after inclusion | 
| Proportion of patients at follow up with eradication of each of the potential pathogens found. | Bacteriological eradication | between 18 up to 24 days | 
| The number of adverse events |  | 3 months after inclusion | 
| Description of patient characteristics and outcomes in the drop-out group. |  | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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sore throat, tonsillitis, randomized controlled trial, primary care, phenoxymethylpenicillin