What to do for a patient diagnosed with streptococcal pharyngitis (strep throat) being treated with amoxicillin (amoxicillin) but not improving and has developed new oral ulcers?

From the Guidelines

If a patient with strep throat is not improving on amoxicillin and has developed new mouth sores, they should see their healthcare provider immediately for reevaluation, as this could indicate antibiotic resistance, a viral co-infection, or possibly a serious reaction to medications. The development of new mouth sores in a patient being treated with amoxicillin for strep throat is a concerning symptom that requires prompt medical attention. According to the Infectious Diseases Society of America guidelines 1, amoxicillin is an effective treatment for strep throat, but the emergence of new symptoms suggests that the current treatment may not be effective or that there may be a complication.

Possible Causes and Next Steps

• The lack of improvement on amoxicillin could indicate bacterial resistance, in which case the healthcare provider may need to switch to a different antibiotic, such as clindamycin (300-450mg three times daily for 10 days) or azithromycin (500mg on day 1, then 250mg daily for 4 more days) 1.
• The new mouth sores could be related to the infection, a medication reaction, or another condition like oral thrush, which can develop with antibiotic use 1.
• Supportive care with salt water gargles, adequate hydration, and over-the-counter pain relievers like acetaminophen can help manage symptoms while awaiting medical attention.

Importance of Medical Evaluation

It is essential to seek medical attention immediately, as continuing the current antibiotic without medical advice is not recommended, given the lack of improvement and the emergence of new symptoms. The healthcare provider will need to reevaluate the patient's diagnosis and treatment plan to determine the best course of action. As noted in the guidelines 1, certain antimicrobials, such as tetracyclines and sulfonamides, are not recommended for treatment of strep throat, and the use of broad-spectrum cephalosporins is not endorsed due to their broader spectrum and higher cost.

From the FDA Drug Label

To reduce the development of drug-resistant bacteria and maintain the effectiveness of amoxicillin and other antibacterial drugs, amoxicillin should be used only to treat infections that are proven or strongly suspected to be caused by bacteria It is recommended that there be at least 10 days’ treatment for any infection caused by Streptococcus pyogenes to prevent the occurrence of acute rheumatic fever. Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic, or evidence of bacterial eradication has been obtained

If a patient diagnosed with strep throat is being treated with amoxicillin but not improving and has new sores in mouth, the treatment failure should be considered.

• The patient should be re-evaluated to determine the cause of treatment failure, which may include resistance to amoxicillin or presence of another infection.
• Alternative antibiotic therapy may be necessary, and the patient should be monitored closely for any signs of worsening infection or adverse reactions to the new antibiotic.
• The new sores in the mouth should be evaluated to determine if they are related to the strep throat infection or another condition, such as a viral infection or allergic reaction.
• The patient's renal function should be considered when adjusting the antibiotic dose, especially if the patient has severe renal impairment 2.

From the Research

Patient Diagnosis and Treatment

• The patient has been diagnosed with strep throat and is being treated with amoxicillin, but is not improving and has developed new sores in the mouth.
• According to 3, antibiotics provide only modest benefit in treating sore throat, although their effectiveness increases in people with positive throat swabs for group A beta-haemolytic streptococci (GABHS).
• The study 3 also suggests that there is low-certainty evidence that compared with penicillin, carbacephem may provide better symptom resolution post-treatment in adults and children.

Alternative Antibiotic Treatments

• 4 states that there is insufficient evidence to show clinically meaningful differences between antibiotics for group A beta hemolytic streptococci tonsillopharyngitis, and recommends penicillin or amoxicillin as first choice.
• 5 notes that Group A Streptococcus (GAS) has remained susceptible to penicillin and other β-lactams, despite their widespread use for 80 years, but that the failure of treatment for invasive infections with penicillin has been consistently reported.
• Azithromycin has been investigated as a potential candidate treatment for various infections, including viral infections 6, but its use in treating strep throat is not well established.

Considerations for Treatment

• 7 suggests that rapid initiation of antibiotic treatment is crucial in patients with severe infections, but may not be as important for other infectious syndromes.
• The study 7 also concludes that withholding antibiotic therapy until diagnostic results are available and a diagnosis has been established seems acceptable in most cases, unless septic shock or bacterial meningitis are suspected.
• It is essential to consider the patient's specific condition, medical history, and the severity of their symptoms when determining the best course of treatment.