Which medication can a patient with a penicillin allergy safely take?

Levofloxacin is an appropriate choice for a patient with a penicillin allergy because it belongs to a different class of antibiotics known as fluoroquinolones. This class does not cross-react with penicillin, which is crucial for patients who have had an allergic reaction to penicillin or related beta-lactam antibiotics.

Patients with a penicillin allergy must avoid medications that are structurally similar to penicillin, as these may trigger allergic reactions. Cephalexin, for example, is a cephalosporin antibiotic, and there is a potential for cross-reactivity between cephalosporins and penicillins due to structural similarities. Clozapine is an antipsychotic that is not relevant to treating infections and does not regard penicillin allergy. Amoxicillin is another penicillin derivative, making it contraindicated for those with a penicillin allergy.

In summary, levofloxacin is safe for patients with a penicillin allergy because it does not share structural characteristics with penicillin, thereby minimizing the risk of an allergic reaction.