An underactive thyroid treatment is being investigated over fears it could make patients ill when they switch between products.
The Medicines and Healthcare products Regulatory Agency (MHRA) has suspended the licence for levothyroxine 100mcg tablets manufactured by Teva for patients with hypothyroidism.
Levothyroxine is a generic medicine, meaning patients sometimes take different brands of the drug with no ill effects.
But the MHRA said concerns had been raised that the Teva product may not be interchangeable with other levothyroxine 100mcg tablets following reports of “loss of control” of the condition and worries about problems with manufacturing, a statement said.
Only levothyroxine 100mcg tablets supplied under the Teva and Numark brands are affected.
The MHRA said alternative products are available and most patients are unlikely to notice any change if they move to another brand.
Teva tablets will stop being available in the UK within the next few weeks as stocks dry up.
“As a precautionary measure, whilst investigations are ongoing, Teva has voluntarily ceased manufacture and distribution,” the MHRA said.
No further supplies of the tablets should be released for marketing until these issues are resolved, it added.
“If patients feel unwell taking the Teva levothyroxine tablets they should report them to their healthcare professional because adjustments to the dose of levothyroxine may be required.”
Those who could need close monitoring by their GP include pregnant women, people with heart disease and patients taking levothyroxine following treatment for thyroid cancer.