ACCURATE AND TIMELY HEIGHT AND WEIGHT MEASUREMENTS

To encourage the pharmacy workforce to participate in interprofessional efforts to ensure accurate and timely patient height and weight measurements are recorded in the patient medical record to provide safe and effective drug therapy; further,

To advocate that clinical decision support systems and other information technologies be structured to incorporate height and weight to facilitate prescribing, dispensing, and monitoring of drugs for safe and effective dosing; further,

To advocate for laws and regulations that prescribers include either height and weight or weight alone, and date obtained, as a required component of prescriptions for medications that are dosed based on that information.

Rationale

Patients who have clinically significant changes in weight during an admission or between physician visits, or who are at an extreme high or low weight, have a higher risk of medication dosing errors that depend on weight body surface area. Accurate heights and weights in SI units (i.e., kilograms, grams, meters, and centimeters) are an integral part of a physical examination for pharmacists to ensure proper dosing of medications. Certain medications require dosing based on body surface area, and there is a need for healthcare organizations to consistently record patients’ height, as estimation of height or weight can contribute to potential over- or underdosing.

Factors such as clinically significant changes in weight due to fluid overload and subsequent diuresis, patient growth, and weight changes due to changes in caloric consumption complicate the picture of an appropriate weight to record for dosing certain medications. Some healthcare organizations default to a dosing weight that is used for dosing medications alone, while other weight fluctuations recorded on a daily basis are not used to dose medications, whereas other organizations alert pharmacists to a clinically significant change in weight. Leveraging technology to ensure such safeguards are in place is essential, and providing interoperability between the patient’s recorded dosing weight and smart pumps is ideal.

Pharmacists are also seeing an increase in the number of patients at both extremes of weight, and there is a lack of information regarding dosing medications for these populations. ASHP advocates that the Food and Drug Administration develop guidance for voluntary drug dosing studies in these populations, as the need for this guidance is supported by the complexity of drug dosing that can vary based on drug and patient characteristics. Drug product manufacturers should be encouraged to complete pharmacokinetic and pharmacodynamic dosing studies, and to publicly report the results, especially for drugs for which significant weight extremes may have clinical impact.

Dosing medications based on height and weight presents important concerns, particularly for pediatric patients, whose variables can change often, but also for oncology patients and aging populations, for whom toxicities or adverse events are a concern (Lubsch L et al. Patient Weight Should Be Included on All Medication Prescriptions. J Pediatr Pharmacol Ther. 2023;28:380–1). Therefore, regulations that mandate recording of height and weight on orders for medications that are dosed based on height and weight would enhance patient safety.