Thank you for your inquiry.
Many physicians feel that there should be a 30 minute waiting period after an injection of any drug administered in an outpatient facility. This is because all drugs are capable of producing an anaphylactic event (1), and many have been recorded to cephalosporins including ceftriaxone (2). After an injection, most such reactions will occur within 30 minutes, and quite often sooner.
Because anaphylaxis is potentially fatal, and certainly treatable with the immediate injection of epinephrine, it is prudent to have patients receiving any injection stay in the office for observation for 30 minutes.
Thank you again for your inquiry and we hope this response is helpful to you.
Kelkar PS and Li JT. Cephalosporin allergy. New England Journal of Medicine 2001; 345:804-809.
Ernst MR. Anaphylaxis after first exposure to ceftriaxone. Acta Paediatrica 2002; 91(3):355-356.
Phil Lieberman, M.D.