From the Guidelines
Penicillin is the first choice for treating acute sore throat, particularly for group A b-haemolytic streptococcal pharyngitis, due to its proven efficacy, safety, narrow spectrum, and low cost. This recommendation is based on the guideline for the management of acute sore throat, which suggests that penicillin has been the treatment of choice for five decades and is recommended by North American and many European guidelines as the first choice for acute sore throat 1. The study found that although newer antibiotics may seem more effective than penicillin in reducing sore throat symptoms, the differences in efficacy are not clinically important.
Some of the key points to consider when prescribing penicillin include:
- Penicillin formulations, such as penicillin G (parenteral) and penicillin V (oral), as well as extended-spectrum versions like amoxicillin
- Typical adult dosing for penicillin V is 250-500mg every 6-8 hours
- Treatment duration typically ranges from 7-14 days depending on the infection type and severity
- Penicillin is effective against many gram-positive bacteria and some gram-negative organisms
- Patients should be aware of the risk of penicillin allergies, which can range from mild rashes to life-threatening anaphylaxis 1
It's also important to note that group A b-haemolytic streptococci have not developed resistance to any of the penicillins or shown an increase in penicillin minimal inhibitory concentrations over at least five decades 1. However, other antibiotics like cephalosporins may have slightly higher clinical cure rates, the magnitude of the differences is small and not clinically relevant. Therefore, penicillin remains the first choice for treating acute sore throat due to its proven track record and favorable safety profile.
From the FDA Drug Label
The serum half-life of penicillin G correlates inversely with age and clearance of creatinine and ranges from 3.2 hours in infants 0 to 6 days of age to 1. 4 hours in infants 14 days of age or older. Penicillin G is distributed to most areas of the body including lung, liver, kidney, muscle, bone and placenta In the presence of inflammation, levels of penicillin in abscesses, middle ear, pleural, peritoneal and synovial fluids are sufficient to inhibit most susceptible bacteria. Penicillin G is bactericidal against penicillin-susceptible microorganisms during the stage of active multiplication It is not active against the penicillinase-producing bacteria, which include many strains of staphylococci or against organisms resistant to beta-lactams because of alterations in the penicillin-binding proteins, such as methicillin-resistant staphylocci
Key Points:
- Penicillin G has a serum half-life that varies with age and renal function.
- It is distributed to most areas of the body and can penetrate into inflamed tissues.
- Penicillin G is effective against susceptible microorganisms, but not against penicillinase-producing bacteria or those with altered penicillin-binding proteins.
- The dosage should be reduced in patients with severe renal impairment, and additional modifications may be necessary with hepatic disease 2. Main Uses:
- Treatment of infections caused by susceptible microorganisms, such as streptococci and Neisseria meningitidis.
From the Research
Penicillin Overview
- Penicillin is a commonly used antibiotic for treating streptococcal pharyngitis 3, 4, 5, 6, 7
- It is effective against Gram-positive pathogens, Gram-negative cocci, and some spirochaetes and actinomycetes 4
Treatment of Streptococcal Pharyngitis
- Penicillin is the treatment of choice for streptococcal pharyngitis due to its cost, narrow spectrum of activity, and effectiveness 3
- Amoxicillin is equally effective and more palatable than penicillin 3
- Cephalosporins and macrolides are alternative options for patients with penicillin allergy 3, 6
Comparison of Antibiotics
- Cephalosporins may be more effective than penicillin in terms of symptom resolution and clinical relapse 5, 6
- Macrolides may be as effective as penicillin in terms of symptom resolution, but the evidence is uncertain 5
- Carbacephem may be more effective than penicillin in terms of symptom resolution, especially in adults and children 5
Duration of Antibiotic Treatment
- Short-course antibiotic treatment (≤5 days) may be as effective as long-course antibiotic treatment (≥7 days) for acute streptococcal pharyngitis 7
- However, short-course penicillin may be less effective than long-course penicillin in terms of early clinical cure and bacteriological eradication 7