Hospital Pharmacy - April 2018 - 91

Cohen

This error has been reported to the Institute for Safe
Medication Practices (ISMP) in the past with other nitroglycerin products. In one case, a patient's blood pressure
dropped to 80/40 mmHg, requiring transfer to a critical care
unit. In another case, the patient spit out the tablets because
of the intense burning sensation in his mouth.
Unlike most tablet or capsule medications in hospitals,
because of stability issues, nitroglycerin is dispensed in bottles of 25 tablets rather than in unit-dose packaging. The
bottles are often stored on patient care units and may be the
only stock bottle of tablets available on units if a robust unitdose dispensing system exists. Some nurses who are accustomed to unit-dose packaging may not be expecting more
than a single dose in a drug container.
We contacted the FDA and asked the agency to have nitroglycerin manufacturers indicate "0.4 mg per tablet," or "Each
tablet contains 0.4 mg," on the carton and bottle label. A slash
mark (0.4 mg/tablet) should not be used because the slash
might be misinterpreted. For now, package the original amber
glass bottle in a plastic bag or plastic amber vial, and affix a
label listing the per tablet strength as well as standard dosing
information. Remind all practitioners, "If you need more than
3 [pills, vials, or other dosage form], call the pharmacy."

ON-Q Pump for Nerve Block Attached
to IV Line

Figure 1. Some believe a 0.4-mg dose requires all 25 tablets in
the bottle.

25 Sublingual Nitroglycerin, All at Once
The entire contents of a 25-count bottle of sublingual
nitroglycerin tablets have occasionally been administered
erroneously as a single dose to patients with angina. Such
an event nearly happened recently when a nursing student
incorrectly interpreted the strength on the bottle label. The
label on the Greenstone brand nitroglycerin tablet container (Figure 1) stated, "nitroglycerin sublingual tablets,
USP, 0.4 mg" (or other strengths). Elsewhere on the label,
it notes that there are 25 tablets in the container, but one's
eyes might easily miss that because it is not printed close
to the drug name and strength. Because the bottle and tablets are so small, the student nurse thought a single dose
must be all 25 tablets. She poured all the tablets into a
medicine cup to administer them. Fortunately, her preceptor quickly noticed the mistake.

An elastomeric pump (ON-Q device) infusing a local anesthetic was purposefully connected to a peripheral intravenous (IV) line by an alert, hospitalized patient. He was
receiving a continuous nerve block for pain management of
an open fracture of the calcaneus (heel bone). He was in tremendous pain and attempted to help manage his pain by giving himself the drug from the ON-Q device IV. Fortunately,
the patient's nurse quickly identified the misconnection and
took appropriate action. Anesthesia was notified, the patient
was monitored, and the ON-Q pump was discontinued due to
concern for compliance.
It is likely that many hospitals are seeing increased use of
nerve blocks with local anesthetics to reduce opioid use.
Keep in mind that accidental IV infusion of local anesthetics,
including bupivacaine and ropivacaine, is concerning due to
the potential for significant systemic toxicity, including cardiotoxicity. Therefore, increased awareness of patient safety
concerns with elastomeric devices and regional anesthesia is
needed to prevent the likelihood of similar events.
ON-Q devices are also used for epidural infusions, but it
is unclear whether the requirement for new neuraxial connectors (NRFit) will affect elastomeric pumps used epidurally. The pumps do not currently use the new connector, and
if they do in the future, this will require tubing that accepts
the new connector.
Patient selection plays an important role in the safe use of
elastomeric devices, both in and out of the hospital. Still, it is

Table of Contents for the Digital Edition of Hospital Pharmacy - April 2018