pharmacy technician - Ontario College of Pharmacists

ERROR PREVENTION
FOCUS ON
ERROR PREVENTION
Ian Stewart B.Sc.Phm., R.Ph.
ALTERNATIVE DOSAGE FORMS
As a result of drug shortages,
pharmacists often provide an
alternative dosage form, such as
an oral liquid instead of a capsule.
Similarly, a lower strength of a drug
may be dispensed with an increase
in the number of tablets to be
taken. For example, two cephalexin
250mg tablets may be given in the
place of one 500mg cephalexin
tablet.
Pharmacists must, however, be
aware of the potential for error
when making these substitutions.
CASE:
Rx
Clavulin 200mg po bid
Mitte: 7 days
A pediatrician wrote the above
prescription for a one year old
child. On entering the prescription
into the computer, the pharmacy
technician intended that the lowest
cost therapeutically interchangeable
product be dispensed. However, the
Ontario Drug Benefit Formulary
does not list any generic products
that are therapeutically equivalent
to Clavulin®-200 oral suspension.
The technician incorrectly assumed
that Ratio-Aclavulanate® 250F
oral suspension was therapeutically
interchangeable with Clavulin®-200
oral suspension. He therefore
entered the prescription as Ratio-
Aclavulanate® 250F oral suspension
with the label instructions “Give four
millilitres twice daily”.
However, four millilitres of Ratio-
Aclavulanate® 250F oral suspension
contain 50mg clavulanic acid while
five millilitres of Clavulin®-200 oral
suspension contain only 28.5mg
clavulanic acid.
On checking the prescription,
the pharmacist did not detect the
error. Therefore, the child received
almost twice the prescribed dose
of clavulanic acid. As a result of
the excessive dose of clavulanic
acid, the child experienced severe
diarrhea with an accompanying
severe diaper rash. The mother was
understandably not pleased after
learning of the error.
POSSIBLE CONTRIBUTING
FACTORS:
• Clavulin® products contain
amoxicillin and clavulanic acid at
different ratios. See table below.
PRODUCT
Clavulin®-125F oral
suspension
Clavulin®-250F oral
suspension
Clavulin®-200 oral
suspension
Clavulin®-400 oral
suspension
Clavulin®-250 tablets
Clavulin®-500F tablets
Clavulin®-875 tablets
CONTENT
Each 5ml oral suspension contains 125 mg of amoxicillin as the
trihydrate and 31.25 mg of clavulanic acid as the potassium salt
Each 5ml oral suspension contains 250 mg of amoxicillin as the
trihydrate and 62.5 mg of clavulanic acid as the potassium salt
Each 5ml oral suspension contains 200 mg of amoxicillin as the
trihydrate and 28.5 mg of clavulanic acid as the potassium salt
Each 5ml oral suspension contains 400 mg of amoxicillin as the
trihydrate and 57 mg of clavulanic acid as the potassium salt
Each tablet contains 250 mg amoxicillin as the trihydrate and
125mg of clavulanic acid as the potassium salt
Each tablet contains 500 mg amoxicillin as the trihydrate and
125 mg of clavulanic acid as the potassium salt
Each tablet contains 875 mg amoxicillin as the trihydrate and
125 mg of clavulanic acid as the potassium salt
DRUG RATIO
4:1
4:1
7:1
7:1
2:1
4:1
7:1
PAGE 54 ~ SPRING 2011 ~ PHARMACY CONNECTION