The Medicines and Healthcare products Regulatory Agency (MHRA) has released new guidance in relation to generic prescriptions for Levothyroxine.
Levothyroxine for the control of hypothyroidism is usually prescribed generically and as such, pharmacies are able to dispense whichever make of the drug that they have available and patients may experience a change between products on a regular basis.
Although the different brands are shown to have bioequivalence, the MHRA receives Yellow Card reports of patients experiencing adverse events when switched between different Levothyroxine products.
Between 1 January 2016 and 31 December 2020 there were a total of nearly 260 million packs of Levothyroxine dispensed against a prescription in UK community and hospital pharmacies. For the 5-year period between 1 January 2015 and 31 December 2019, the MHRA received 335 Yellow Cards reporting one or more of the terms ‘product substitution issue’, ‘condition aggravated’ or ‘drug ineffective’ with Levothyroxine, the majority of which were from patients rather than healthcare professionals.
These adverse events were mostly consistent with hypothyroidism or hyperthyroidism, and included fatigue, headache, malaise, anxiety, palpitations, pruritus, nausea, myalgia, dizziness, arthralgia, feeling abnormal, alopecia, depression, abnormal weight gain, and insomnia.
The underlying causes for the symptoms are generally unclear. It has been suggested that causative factors could include reduced levothyroxine absorption (e.g. due to gastrointestinal comorbidities), very low thyroid reserve or intolerance or allergy to a particular excipient.
Treatment guidance from the British Thyroid Association[1] acknowledges symptoms can occur in some people on switching brands. For the most part, they could indicate the need for dose adjustment, although some patients still experience symptoms despite tests showing they are biochemically euthyroid.
Advice for Pharmacy Teams
- If a patient is experiencing problems with adverse effects, keep a record of their preferred brand of levothyroxine on the PMR and try to maintain consistency
- Where it is not possible to guarantee which brand of Levothyroxine is kept at the pharmacy, refer the patient back to the prescriber who should be able to prescribe the exact brand
- See the Tariff Tip – Specifying brand/Manufacturer for more information on how both paper and electronic prescriptions need to be written for correct reimbursement
Tariff Tip
- See the Tariff Tip – Specifying brand/Manufacturer for more information on how both paper and electronic prescriptions need to be written for correct reimbursement
- If symptoms or poor control of thyroid function still persists despite adhering to a specific product, refer the patient back to their clinician as the MHRA suggests that prescribing Levothyroxine in an oral solution formulation may result in better control