PHARMACY CONNECTION ARTICLE

Focus on Error Prevention: Determining the Clinical Purpose of a Prescription

Published on: August 1, 2016

By Ian Stewart B.Sc.Phm., R.Ph.

When dispensing medications, pharmacists must review each prescription for a medication that a patient is taking for the first time to ensure that the medication is the most appropriate for the specific patient and the dose and instructions for use are correct.

In a large number of cases, this cannot be accomplished unless the pharmacist is aware of the indication for use. The optimal dosage regimen will often be determined by the clinical purpose of the drug.

Case 1:

Rx
Medication: Dukoral® Oral Vaccine
Sig: Use as directed
Quantity: Two doses

The above medication was prescribed for a five year old child. The prescription was taken by the child’s mother to a local community pharmacy for processing. The vaccine was prepared and dispensed by the pharmacist.

While counselling the parent on the use of the vaccine, the pharmacist asked the appropriate questions including,

  1. When will the child be travelling?
  2. Has the child taken Dukoral® previously and if
    so when?
  3. What did the doctor tell you about the purpose for taking Dukoral®?

The pharmacist learnt that the child was travelling to Africa in approximately one month and had not taken Dukoral® previously. The parent also indicated that the physician had prescribed Dukoral® because of cholera concern.

Based on the information received, the pharmacist determined that the patient must take three doses of Dukoral® (not two) at least one week apart1. The pharmacist therefore contacted the prescriber to change the prescription accordingly. The parent was also advised to start the vaccine immediately as protection against cholera will start approximately one week after the third dose is given.

Case 2:

Rx
Medication: Valacyclovir
Sig: 1000mg every 12 hours
Quantity: Six doses

The above prescription was processed at a local community pharmacy. Six valacyclovir 1000mg tablets were dispensed with the instructions to take one tablet every twelve hours until finished.

While patient counselling, the pharmacist noticed that the patient was developing a cold sore. The pharmacist confirmed that the valacyclovir was indeed being taken to treat the cold sore.

The pharmacist contacted the prescriber to discuss the recommended dosage regimen for treating cold sores (Herpes Labialis) was valacyclovir 2000mg (not 1000mg) every twelve hours for one day only2. The physician acknowledged the 2000mg dosage and indicated that he had provided six doses to treat future outbreaks and not to be used continuously.

The prescription was therefore changed to valacyclovir 2000mg every twelve hours for two doses only, plus two refills.

Recommendations:

  • To ensure the patient receives the most appropriate drug therapy, always gather the indication for use from the prescriber or patient whenever possible. If this information cannot be obtained prior to the dispensing of the drug, use open ended questions to gather this information from the patient during patient counselling.
  • Always contact the prescriber to clarify ambiguous information. This includes unusual prescribed
    quantities based on the indication for use.
  • Remember that pharmacists may adapt prescriptions by changing the dose as per the expanded scope of practice3

Please continue to send reports of medication errors in confidence to Ian Stewart at: [email protected].

Please ensure that all identifying information (e.g. patient name, pharmacy name, healthcare provider name, etc.) are removed before submitting.

REFERENCES

  1. Dukoral® product monograph available at: https://www.dukoralcanada.com/download/consumer-info-en.pdf
    Accessed June 29th, 2016.
  2. Valtrex® product monograph available at: http://ca.gsk.com/media/593038/valtrex.pdf
    Accessed June 29th, 2016
  3. Expanded Scope of Practice orientation manual. Accessed June 29th, 2016. (No longer available)
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