Adacel (Tdap) and Daptacel (DTaP): Don't Confuse Them

Although most children are protected against pertussis by vaccination with diphtheria and tetanus toxoids and acellular pertussis (DTaP) during childhood, immunity wanes over time and leaves adolescents and adults vulnerable to infection. According to the Centers for Disease Control and Prevention, adults aged 19 to 64 years and adolescents aged 11 to 18 years accounted for 29% (n = 7481) and 34% (n = 8897), respectively, of the reported pertussis cases in 2004.

In order to address this concern, the Advisory Committee on Immunization Practices (ACIP) released finalized guidelines (www.cdc.gov/mmwr/PDF/rr/rr5503.pdf) in May 2006. The guidelines recommend the routine use of a single dose of a newly available tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine for adults aged 19 to 64 years and adolescents aged 11 to 18 years to replace the next booster dose of tetanus and diphtheria toxoids vaccine. The ACIP also recommended Tdap for adults who have close contact with infants less than 1 year of age (infants are at the highest risk of pertussis-related complications and death) and for health care personnel.

ISMP has become aware of several mix-ups between DAPTACEL (diphtheria and tetanus toxoids and acellular pertussis vaccine adsorbed [DTaP]) and ADACEL (tetanus toxoid and reduced diphtheria toxoid and acellular pertussis vaccine adsorbed [Tdap]). Thirteen adult patients at one clinic and 7 adult patients at another were vaccinated with the pediatric vaccine Daptacel instead of the intended Adacel. Fortunately, none of the patients appeared to have experienced any unusual vaccine reactions despite the fact that the pediatric formulations contain greater amounts of the pertussis antigen.

The similarities of the brand names, generic designations, and vaccine abbreviations (Tdap and DTaP) were thought to have contributed to the confusion. The similarities of the packaging also may contribute to these errors (Figure).

Reporters also have told ISMP that some commonly used drug references, pharmacy computer systems, and drug wholesalers incorrectly reference the component antigens of Adacel as diphtheria, tetanus, acellular pertussis, even though this differs from the order of the component product names on the manufacturer's packaging and labeling. As a result, it is easier to confuse these products in drug listings and means that clinicians may not be able to search drug references, computer systems, and drug inventory/purchasing lists using the order of the component products as found in the package labeling.

Safe Practice Recommendations

To prevent mix-ups between these 2 products at practice sites, please share this article with professional colleagues to alert them to this issue.

Here are some suggestions:

• Separate the pediatric and adult formulations, and place alerts on the products (eg, "Adult" or "Pediatric")
• Place alerts, where feasible, in the computer to warn practitioners about the differences between the adult and pediatric formulations
• Verify patient age prior to dispensing or administering any vaccines
• Check the computer system to see how the vaccine name is displayed
• Consider changing the presentation of the component products in the computer system to reflect the actual product labeling