麻豆传媒

AUSTIN, Texas -- Knowing where a particular drug was classified in the FDA's "pregnancy categories" significantly impacted a clinician's decision about whether or not to prescribe certain drugs to their pregnant patients, researchers said here.

In a randomized survey, clinicians who only had information about a drug, and were not aware that it was Category B or Category C were significantly less likely to prescribe it to their patients than those clinicians who had that information, reported Angela Robinson, MD, of Yale New Haven Health in Greenwich, Connecticut, and colleagues.

The FDA instituted the (PLLR) in December 2014, replacing the 30 year-old A, B, C, D and X, Robinson said in a at American College of Obstetricians and Gynecologists (ACOG) annual meeting

In its place were three detailed subsections providing "a narrative summary" of maternal and fetal risk and supporting clinical data. She stated that the agency's fear was that the category system was "simplistic and misleading," and could imply that "the degree of risk" interprets with each letter. The PLLR "was designed to give healthcare providers more useful and up-to-date information about the effects of medicines during pregnancy," she said.

Because over 6 million pregnant women annually take three to five prescription drugs, and a third of those would be classified as categories C, D or X, Robinson's group decided to test the impact of the removal of pregnancy categories with a small survey of healthcare providers.

In what was described as "the first study addressing this change" in labeling system, researchers conducted a randomized survey at two centers in New York City at two annual specialty meetings. Participants were given four clinical vignettes, one apiece for categories A, B, C and D, which included both indications for the drug in question and detailed drug information. Participants were randomized as to whether or not the pregnancy category was also included with the vignette. Respondents then used a 5-point Likert scale to determine how likely they were to prescribe the drug.

The majority of respondents were women and over half were ages 35 to 54. Two-thirds were ob/gyn generalists, and a little under 60% had 0-4 years experience.

They found that physicians who were blinded to the category letter for category B drugs were significantly less likely to prescribe them. A multivariate analysis found the same to be true for both category B and category C drugs.

A secondary analysis also examined a participant's (MSTAT-II) score to determine whether an individual's tolerance of ambiguity was a predictor of certain prescribing patterns. Robinson said they found these scores "poorly correlated" with the likelihood to prescribe medications.

Robinson noted that the drugs examined were all "relatively new drugs," as researchers had to find drugs that complied with both the old labeling formatting and the new standards of the PLLR.

The findings indicated the FDA's rule change was "just the opposite of what the FDA hoped to accomplish with the new labeling system," she noted. "This presents new challenges for clinical decision-making, which could result in decreased access to medications for pregnant women. The system should be tested and examined more closely using practitioners and consumers."