From the Guidelines
For a patient with strep throat not responding to amoxicillin who may have developed an amoxicillin rash, I recommend switching to azithromycin as the next best antibiotic option. Azithromycin can be prescribed as 12 mg/kg once daily (max = 500 mg) for 5 days for children, or 500 mg on day 1 followed by 250 mg daily for 4 more days for adults 1. Regarding the rash, it is essential to discontinue amoxicillin immediately and document the reaction in the patient's chart. If the rash is mild (no mucosal involvement, no systemic symptoms), an antihistamine like diphenhydramine 25-50 mg every 6 hours can help manage symptoms. For more severe reactions with fever, joint pain, or mucosal involvement, the patient should be evaluated immediately. Some key points to consider when choosing an alternative antibiotic include:
- The mechanism of action: azithromycin is a macrolide that affects protein synthesis by binding to the 50S ribosomal subunit, which is different from penicillins 1.
- The resistance pattern: the guideline notes that resistance of GAS to azithromycin is well-known and varies geographically and temporally, but it is still a recommended option for patients with penicillin allergy or intolerance 1.
- The dosage and duration: the recommended dosage and duration of azithromycin are crucial to ensure effective treatment and minimize the risk of resistance 1. It is also important to note that other options like clindamycin or cephalexin may be considered, but azithromycin is a suitable choice due to its efficacy and safety profile, as supported by the guideline 1.
From the Research
Alternative Antibiotics for Strep Throat
If a patient with strep throat does not improve with amoxicillin and experiences a possible amoxicillin rash, alternative antibiotics can be considered. The choice of alternative antibiotic depends on various factors, including the patient's allergy status and the severity of the infection.
- Cephalosporins: Cephalosporins, such as cephalosporin, may be effective alternatives to penicillin for treating strep throat 2. However, the evidence is uncertain, and more research is needed to confirm their effectiveness.
- Macrolides: Macrolides, such as azithromycin, may also be considered as alternative antibiotics for strep throat 2, 3. However, azithromycin has been shown to have lower bacteriologic eradication rates compared to penicillin V 3.
- Clindamycin: Clindamycin may be effective as an adjunctive treatment to β-lactam antibiotics in patients with severe invasive group A β-haemolytic streptococcal infections 4.
Handling Amoxicillin Rash
If a patient experiences a rash while taking amoxicillin, it is essential to monitor the patient's condition closely and adjust the treatment plan as needed.
- Stop amoxicillin: If the rash is severe or worsens over time, amoxicillin should be discontinued, and an alternative antibiotic should be considered 5.
- Monitor for allergic reactions: Patients who experience a rash while taking amoxicillin should be monitored for signs of allergic reactions, such as anaphylaxis, and treated promptly if necessary 5.
- Consider alternative antibiotics: Alternative antibiotics, such as cephalosporins or macrolides, may be considered for patients who experience a rash while taking amoxicillin 2, 3.