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Safety Concerns Over Drug Dosage Measurements
In the wake of more than 30 serious adverse event reports relating to dosing errors, the Institute for Safe Medication Practices is advocating for pharmacists and other healthcare professionals, as well as pharmacy computer system and e-prescribing system vendors, to remove or prevent the use of “teaspoonful” and other non-metric measurements in prescription directions in order to better protect patients.

Mix-ups involving confusion between measuring medications in milliliters or teaspoonfuls and other non-metric measurements have resulted in serious injuries to children and adults requiring emergency treatment or hospitalization, according to the institute. Variances in spoon or medication cup or dose dispenser size also increase the risk for over- or under-medicating. When there is confusion between teaspoon dosing and mL, patients often receive five-fold underdosing or overdosing of liquid medications.

Prescribers and providers are encouraged to reduce the risk of drug dosing confusion by using only metric measurements, especially with oral liquid medications. The ISMP has recommended the following steps to prevent errors:

Cease use of patient instructions that use “teaspoonful” or any other household or non-metric measurements on prescriptions and medication labels

Express doses for oral liquids using only metric weight or volume (e.g., mg or mL)

Take steps to ensure patients have an appropriate device to measure oral liquid volumes in milliliters

Coach patients and caregivers on the proper use and cleaning of measuring devices and, when possible, observe a return demonstration to confirm their understanding of accurate dosing technique

Asthma Drug Concerns Emerge
The U.S. Food and Drug Adminstration is evaluating interim safety findings from an ongoing study of omalizumab (Xolair) — a subcutaneously injected monoclonal antibody that inhibits inflammatory responses to allergens that provoke asthma attacks. It is approved for use by adults and adolescents (12 years of age and older) with moderate to severe persistent asthma who test positive for reactivity to a perennial airborne allergen, and whose symptoms are inadequately controlled with inhaled corticosteroids.

Interim data from an ongoing study of about 7,500 patients, two-thirds of whom are treated with omalizumab, suggests an increased number of cardiovascular and cerebrovascular adverse events among the patients treated with the drug. The study, titled Evaluating the Clinical Effectiveness and Long-Term Safety in Patients with Moderate to Severe Asthma, is an observational study assessing the long-term safety profile of omalizumab over five years.

The interim data suggests a disproportionate increase in ischemic heart disease, arrhythmias, cardiomyopathy and cardiac failure, pulmonary hypertension, cerebrovascular disorders, and embolic, thrombotic, and thrombophlebitic events in patients treated with omalizumab compared with the control group of patients not given the drug.

Although the FDA is not recommending labeling changes or advising patients to stop taking omalizumab at this time, it is encouraging healthcare providers and patients to be aware of the risks and benefits associated with drug use.

Patients receiving omalizumab therapy should be aware of early warning signs of stroke, heart failure, myocardial infarction, and deep vein thrombosis. They must understand the importance of immediately seeking medical attention for any adverse effects. Abrupt discontinuation in light of the recent safety concerns should be discouraged. Patients desiring to discontinue therapy should consult with their prescribing healthcare providers.

Susanne Pavlovich-Danis, RN, MSN, ARNP-C, CDE, CRRN, of S & D Comprehensive Consulting Inc. is a freelance writer.

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