Rocephin (ceftriaxone) ok in penicillin allergic patients

http://findarticles.com/p/articles/mi_m0689/is_2_55/ai_n16084680/pg_4?tag=artBody;col1
For patients truly allergic to penicillin, the risk of a reaction from a cephalosporin with side chains that differ from penicillin/amoxicillin (cefuroxime, cefpodoxime, cefdinir, and ceftriaxone, as endorsed by the AAFP) is so low that use is justified and medico-legally defensible by the currently available evidence...
Penicillin-allergic patients have indeed shown an increased incidence of allergic reactions to cephalothin, cephaloridine, cephalexin, cefadroxil, cefazolin, and cefamandole. However, the risk has been overestimated because most studies reporting this cross-reactivity were flawed (because penicillins were contaminated with cephalosporins) and then failed to account for the fact that penicillin-allergic patients have a 3-fold increased risk of allergic reactions even to nonrelated drugs. (51)
(51.) Smith J, Johnson J, Cluff L. Studies on the epidemiology of adverse drug reactions: II. An evaluation of penicillin allergy. N Engl J Med 1966; 274:998-1002.