Interactives: Case Studies (April 2020)
Two retail pharmacy case studies are presented.
JT calls to inquire about the human papillomavirus (HPV) vaccination schedule for her son CT, who just turned 17. She wants to make sure that he receives the appropriate vaccinations before heading off to college in the fall. CT received 1 dose of the HPV vaccine when he was 11 but did not get subsequent doses. JT wants to know whether her son needs to restart the series or whether he can just get another dose now.
What advice do you give her?
A local physician’s assistant (PA) calls the pharmacy to ask about VB, a 19-year-old patient at his clinic who tested positive for strep throat. The PA says that his patient is allergic to penicillin, which is documented in the chart as a skin irritation that VB experienced as a child. The PA wants to prescribe cefdinir (Omnicef) and to know whether it would be safe, given this allergy.
How do you respond?
CASE 1: CT does not need to restart the series. Because he was younger than 15 years at the time of his first dose, he needs only 1 more dose to complete the 2-dose series. In a 2-dose series, the second dose is recommended 6 to 12 months after the first dose, with no maximum interval. Because CT received his first dose 6 years ago, he can receive the second dose now.
CASE 2: Because the allergy is documented as a minor rash that occurred a long time ago, a third-generation (or later) cephalosporin, such as cefdinir, is appropriate to prescribe. Unlike the first- and second-generation cephalosporins, third-generation agents do not share the same R1 side chain with penicillin. It is thought that these side chains, not the β-lactam ring itself, are responsible for the cross-reactivity. Despite a low risk, the PA should counsel VB to self-monitor for any signs and symptoms of an allergic reaction and to call the office with any concerns.
Stefanie C. Nigro, PharmD, BCACP, CDE, BC-ADM, is an associate clinical professor at the University of Connecticut School of Pharmacy in Storrs.