Hospital Pharmacy - June 2018 - 143

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Cohen and Smetzer
to the approval of Astagraf XL in the United States, the manufacturer and FDA carefully assessed the error experiences with
Advagraf to develop labeling and naming strategies to help
mitigate confusion. For example, XL was added to the trade
name Astagraf in the United States to help draw attention to its
extended-release formulation.
However, we can still learn from these cases and others, as
the way tacrolimus appeared on electronic prescribing system
screens frequently contributed to these errors, as it often does
in the United States. In one case, a physician mistakenly
ordered "tacrolimus MR 0.5 mg capsules" when he intended
to select "tacrolimus 0.5 mg" on the screen ("MR" means
modified-release). When drugs are listed by their generic
names, and different formulations exist, the eyes typically
capture the name of the drug first, and then may miss any
evidence that one may be selecting the wrong formulation.

Look-Alike Medication Names
ISMP has documented more than 800 confused drug name
pairs that have been published in our newsletters. One name
pair that we have recently been asked to consider including
on our list of confused drug names is tacrolimus and tamsulosin, an alpha1 blocker used to treat benign prostatic hyperplasia (and off-label to treat bladder outlet obstruction
symptoms and distal ureteral calculi expulsion). Although
the available strengths differ, we discovered that several
mix-ups between tacrolimus 0.5 mg and tamsulosin 0.4 mg
have been reported, some leading to patient harm.
For example, a liver transplant coordinator reported 2 incidences where outpatient pharmacies had dispensed tamsulosin 0.4 mg to patients who had been prescribed tacrolimus 0.5
mg. Tragically, both reported cases were believed to have
contributed to the rejection of the transplanted liver. In another
case, a patient had been hospitalized with symptoms of organ
transplant rejection. During collection of a home medication
list, a nurse noticed that the capsules in the patient's vial of
medication labeled as tacrolimus 0.5 mg were quite different
in color than she expected. She contacted a pharmacist, who
identified the capsules as tamsulosin 0.4 mg.
Confusion among brand names has been reported less frequently. In one case, it was discovered that a patient with a high
tacrolimus serum level had been given Prograf 5 mg capsules,
intended for another family member, instead of his prescribed
PROSCAR (finasteride) 5 mg. Apparently, the Prograf had
been placed in the patient's dosing pill box by a family member
in error instead of Proscar. Fortunately, the patient's creatinine
remained stable and he was not harmed by the error.

Confusion When Dispensing More Than One
Strength for the Patient's Dose
With variable tacrolimus dosing based on the patient's weight,
type of organ transplant, response to therapy, adjuvant immunosuppressants, and other factors, any of the available capsule

or tablet strengths might be needed to fill a prescription.
However, the pharmacy may not stock all strengths, and/or several strengths of the drug may be needed to accommodate the
patient's total daily dose. This can lead to dosing confusion,
particularly during the dispensing and administration phases of
the medication-use process.
For example, dispensing errors have involved a mismatch
between the total prescribed dose and the capsule or tablet
strengths dispensed to provide each dose. In one case, the
prescriber ordered tacrolimus 5 mg orally every 12 hours (10
mg daily). However, the pharmacy only stocked the 0.5 mg
strength and a limited supply of the 1 mg strength. The prescription was mistakenly filled with the 0.5 mg capsules,
with directions to take 2 capsules by mouth every 12 hours,
along with 1 mg capsules, with directions to take 3 capsules
by mouth every 12 hours. This resulted in the patient receiving only 8 mg of the drug daily.
Patient confusion is also a concern when various strength
capsules or tablets are dispensed. For example, a postrenal
transplant patient was prescribed tacrolimus 6 mg orally every
12 hours. The initial prescription was partially filled with 1 mg
capsules, with directions to take 6 capsules for each dose every
12 hours, until the supply of 5 mg capsules could be ordered to
lower the cost of the prescription medication. Once the 5-mg
capsules arrived in the pharmacy, the remainder of the prescription was filled using 5 mg capsules along with 1 mg capsules to achieve each 6 mg dose. A pharmacist had placed a
note on the bag containing the medication in the will-call area
as a reminder to talk to the patient about the change in capsule
strength and the new directions for use. However, the note was
not noticed, and patient counseling never occurred.
Although new directions had been provided on the labels of
the 2 newly dispensed vials, the patient combined all the capsules into the initial prescription vial. The patient then took 6
capsules in the morning and 6 at night, as indicated on the label
instructions. A month later, a very high serum tacrolimus level
was obtained. Inspection of the patient's supply of tacrolimus
showed the 2 strengths commingled in the vial, with the 1 mg
capsules predominantly on the bottom (meaning the patient
took mostly the 5 mg capsules each day, up to 60 mg daily).

Manufacturer Label Confusion
One of the extended-release formulations of tacrolimus,
Astagraf XL, comes in a bottle with a label that has occasionally confused patients who were dispensed the product in the
sealed manufacturer's (Astellas Pharma US) container. In 1
case, a patient who was previously taking immediate-release
tacrolimus 3 mg every 12 hours had just been converted to 6
mg of the extended-release product Astagraf XL daily. The
new prescription for Astagraf XL had been filled using sealed
manufacturers' bottles of the 1 mg capsules, onto which
pharmacy labels had been applied, directing the patient to
take 6 capsules daily. However, 1 week later, lab work
showed that the tacrolimus trough had dropped to an

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