This column was prepared by the Institute for Safe Medication Practices (ISMP), an Emergency Care Research Institute affiliate.
A pediatric patient was prescribed Hemlibra® (emicizumab), a factor IXa- and factor X-directed antibody indicated for prophylaxis against bleeding episodes in patients with hemophilia A. The drug is intended for use under the guidance of a health care provider. However, after proper training, and if a health care provider determines that it is appropriate, a patient or caregiver may administer Hemlibra. In one case, a patient’s parent was preparing 33 mg (or 0.22 mL) of Hemlibra to administer subcutaneously to the child. However, they became confused about how much Hemlibra should be drawn into the parenteral syringe. For clarification, they contacted the specialty pharmacy and began a conversation with the on-call answering service. Before the answering service could direct the call to the appropriate person, the parent became further confused and frustrated enough to end the call and administer the dose. Unfortunately, they drew up the entire contents of the vial (0.4 mL or 60 mg) into a syringe and administered almost double the prescribed dose.
Multiple preparation steps and supplies are needed to prepare and administer a dose of Hemlibra. For example, for the patient’s dose described above, the caregiver would need the vial of medication, alcohol swabs, a 1 mL parenteral syringe, a transfer needle, and an injection needle. Without proper training and experience, working with multiple items could cause anxiety and confusion for a caregiver. In addition, maintenance doses of Hemlibra may be administered once a week, once every two weeks, or once every four weeks. This means there may be a long period of time between doses, which can contribute to anxiety and confusion the next time they administer a dose. Thus, it is critical that the prescriber and/or specialty pharmacy provide training and confirm, via return demonstration, the caregiver’s ability to prepare and administer the product properly and safely. If this cannot be done, a health care practitioner should administer the medication.
The reporter indicated that the parent also may not have understood the directions printed on the prescription label. The pharmacy prescription label’s main purpose is to support the patient or caregiver to use the medication correctly and safely. It is important for both prescribers and pharmacy staff to provide directions that are easily understood by patients and caregivers. To help accomplish this, the patient directions should only include the unit of measure the patient or caregiver will need for measuring the correct amount of medication to administer the specific dose. In the case above, the instructions could have read: “Inject 0.22 mL subcutaneously in the morning once a week.”
Ensure the dosing instructions on the prescription label match the dose marking(s) on the provided dosing device. Do not use multiple units of measure or combine both the dosage unit and the volume (eg, 33 mg [0.22 mL]) on the prescription label, as this can cause confusion for the caregiver or patient.