Avoid all β-lactams (penicillins, cephalosporins, carbapenems) in patients with a documented severe non-lgE-mediated reaction to penicillin: interstitial nephritis, hepatitis, hemolytic anemia, serum sickness, severe cutaneous reactions [e.g. Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia & systemic symptoms (DRESS)], including their use for graded challenge, desensitization, or skin testing. Use a non-β-lactam antibiotic.

Although some dental prophylaxis guidelines recommend cephalexin, it is not an appropriate option for patients allergic to amoxicillin (due to similar side chain and risk of cross-reactivity), nor is cephalexin active against many oral organisms.