Article date: June 2012
Tacrolimus is an immunosuppressant drug which may be given orally to prevent or treat organ transplant rejection. Tacrolimus has a narrow therapeutic index, and even minor differences in blood levels have the potential to cause graft rejection reactions
Oral tacrolimus and inadvertent switching between products
Since 2008, the MHRA has been aware of reports of unintended switching between different pharmaceutical forms of oral tacrolimus products in patients who have been treated with tacrolimus for the prevention of organ transplant rejection. Graft rejection reactions and tacrolimus toxicity have resulted from a small number of these unintended switches between products.
Prescribing oral tacrolimus products
As there are a growing number of tacrolimus products available on the UK market, the Commission on Human Medicines (CHM) has now advised that the risk of inadvertent switching between the different products may increase.
Therefore, as a precautionary measure, the CHM has updated its advice on the safer use of oral tacrolimus products and recommends that all oral tacrolimus products should be prescribed and dispensed by brand name only. This supersedes previous advice regarding the prescribing, dispensing and interchangeability of different tacrolimus products (see Drug Safety Update January 2009, February 2010, and May 2010).
A letter on the updated advice for oral tacrolimus products was sent to healthcare professionals in May 2012. The purpose of the new advice is to ensure maintenance of therapeutic response when a patient is stabilised on a particular brand, and to minimise the risk of inadvertent switching between products from different suppliers. As all tacrolimus products are approved in the UK with a brand name, the easiest way to achieve this is to prescribe by brand name only.
Important: careful therapeutic monitoring is recommended for any switching between tacrolimus brands. The currently available brands of oral tacrolimus are:
- immediate-release capsule taken twice daily including:
- prolonged-release capsule taken once daily (Advagraf)
- granules for oral solution taken twice daily (Modigraf)
If the exact brand of tacrolimus is not clearly stated on the prescription, the dispensing pharmacist should check with the prescriber to ensure that the appropriate medicine is dispensed.
Changing oral tacrolimus products
This updated recommendation does not preclude patients changing to a different tacrolimus brand if the prescriber considers this to be of benefit to the patient. However, changes between different brands (which may or may not involve changes in dosing regimen), should always be accompanied by careful therapeutic monitoring under the supervision of an appropriate specialist.
Advice for healthcare professionals and patients:
- prescribers should prescribe oral tacrolimus products by brand name only. When prescriptions have been previously written using the generic name, the brand on which the patient is stabilised should be established to ensure that the patient is supplied with the same product
- if a prescriber intends to switch between any tacrolimus brand, careful medical supervision and therapeutic monitoring are required
- pharmacists should always dispense the exact brand prescribed; they should contact the prescriber if the prescription is not clear to ensure the appropriate medicine is dispensed
- patients should be advised to take careful note of the brand name of their usual tacrolimus medicine and should check with their doctor or pharmacist if they receive a different brand or if they have any other questions about the prescription, eg about the dose
BNF section 8.2 Drugs affecting the immune response
Article citation: Drug Safety Update June 2012, vol 5 issue 11: A1