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Preventing Medication Errors: Tacrolimus Case

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Prescriber Update 33(1): 1-2
March 2012

New formulations of existing medicines can sometimes cause confusion, especially when there is a change to dosing frequency.

This article draws prescribers' attention to the new prolonged-release formulation of tacrolimus that is now approved for use in New Zealand.

Tacrolimus is currently marketed as Prograf and the new formulation as Prograf XL. Importantly, tacrolimus has a narrow therapeutic index and medication errors have the potential to significantly harm patients.

Prograf

Is an immediate release formulation intended for twice daily dosing.

Prograf XL

Is a prolonged release formulation intended for once daily dosing

The manufacturer of Prograf and Prograf XL has employed a number of methods to reduce the risk of confusion between the two brands, such as:

colour coding of the capsules and blisters, with distinctive colouring for immediate versus prolonged release capsules
the use of packing overwrap to highlight the XL formulation and patient dosing cards
the use of shelf talkers for pharmacies to reduce the potential for picking errors.

In addition, the manufacturer is attempting to introduce warning flags on prescribing and dispensing software.

International experience

Cases of medication errors, due to confusion over tacrolimus formulations, have already been reported in other countries. In some cases, these errors resulted in serious adverse reactions, including rejection of transplanted organs¹.

Errors have occurred at the prescribing, dispensing and administration of tacrolimus.

Key Messages

To reduce the potential for error, tacrolimus should be prescribed with a full description of the drug, the formulation (immediate relase or prolonged release), the strength and frequency of dosing.
Prescribers should also consider adding the brand name to prescriptions.
Pharmacists should contact the prescriber if the strength, brand or formulation is not absolutely clear.
Switching between formulations or brands of tacrolimus requires careful medical supervision and may require therapeutic monitoring and re-titration.
Patients should be advised to familarise themselves with the name and appearance of their tacrolimus medication and check with their doctor or pharmacist if they have any concerns about the medicine they receive.

References

Medicines and Healthcare Products Regulatory Agency. 2010. Oral tacrolimus products: measures to reduce risk of medication errors. Drug Safety Update, 3(10): 5

MEDSAFE

New Zealand Medicines and Medical Devices Safety Authority