Barriers in the quest for quality drug information: salutary lessons from TGA-approved sources for thyroid-related medications.

Product information (PI) for thyroid-related medications endorsed by the Therapeutic Goods Administration, as reproduced in the commonly used compilation publications June 2006 MIMS (Monthly index of medical specialties) annual, MIMS Online and the Australian prescription products guide 2006, was evaluated to see whether it reflects contemporary therapeutic practice. Compared with current medical literature, these PI-based sources provide inadequate, inaccurate or outdated therapeutic directives. Examples include: Incorrect advice that thyroxine therapy should always begin at very low dosage. Failure to recommend increased thyroxine dosage early in pregnancy (thus placing the offspring of women being treated for hypothyroidism at risk of impaired fetal brain development). Incorrect and potentially unsafe advice to treat thyrotoxicosis with stable iodide in late pregnancy. Failure to advise serial adjustment of antithyroid drug dosage until after a patient becomes euthyroid (this can result in iatrogenic thyroid dysfunction). Outdated advice that antithyroid drugs are not compatible with breastfeeding. Recent initiatives to upgrade consumer medicine information (CMI) appear to accept PI-based sources as a reliable benchmark for CMI. That inference is not warranted for thyroid-related medications. Accountability for the updating of clinical information in PI needs to be defined, and the process for updating PI may need to be modified. Quality drug information, both PI and CMI, depends on fluent, evidence-based collaboration between suppliers, regulators, prescribers, specialist clinicians and consumers.