Antibiotic Selection for Strep Pharyngitis in Adults

Antibiotic Selection for Strep Pharyngitis in Adults

23 year old male. Rapid strep is positive.

Which antibiotic do you prescribe?

• Amoxicillin 1g daily x 10d or 500mg q12 x 10d
• Penicillin VK 500mg QID x 10d

What if my patient in non-compliant, or has limited access to resources?

• Penicillin G Benzathine (Bicillin L-A) IM 1 time dose

What if my patient has an allergy to penicillin?

• Cephalexin 500mg bid x 10d

Why are you recommending that I give Keflex to my patient with a penicillin allergy? I thought there was cross-allergy between cephalosporins and penicillin due to their similar molecular structure?

Evidence is inconclusive and the often quoted “10% cross-allergy between penicillin-allergic patients who take a cephalosporin” is a myth. HOWEVER, it is best to avoid even a small risk of cross-allergy in the subset of patients with a true and severe allergy (anaphylaxis) to penicillin.

What if my patient has a severe allergy (hx of anaphylaxis) to penicillin?

• Clindamycin 300mg q8 x 10d
• Clarithromycin 250mg q12 x 10d
• Azithromycin 500mg daily x 5d

So, again, why not just give one of the agents listed above and avoid even a tiny risk of an allergic reaction in patients who say they have an allergy to penicillin?

Resistance of GAS to clarithromycin and azithromycin is well known and these are not the best agents to use when superior alternatives can be given. Clindamycin has many side effects and should be avoided if other agents can reasonably be given.