Dr Ursula Mason, chair of the Royal College of General Practitioners Northern Ireland, said finding a substitute “can cause real anxiety for patients”.
“This can be particularly so for HRT medication when a woman has found a preparation that works well for them,” she said.
“Patients can be assured that the protocol in place only allows a substitution for exactly the same active ingredient at the same dose.
“If a woman finds that for whatever reason the new formulation is not managing their symptoms or they are having side effects, it would be important that they contact their GP to discuss both their symptoms and the options available around suitable alternatives.”
The Department of Health said it was aware of “supply disruptions” affecting some HRT medications across the UK, including ongoing issues with Estradot transdermal patches and a more recent disruption affecting FemSeven Conti patches.
“Communications have been issued to healthcare professionals regarding the products affected, including advice on suitable alternatives that remain available,” it said.
It added: “Serious Shortage Protocol (SSPs) for Estradot transdermal patches are currently in place until 8 January 2027, permitting pharmacists to supply alternative products to patients without the need for a new prescription, where the patient has agreed to this.
“If patients cannot access their prescribed medication or have concerns about an alternative, they should speak to a healthcare professional for advice about their treatment options.”