Hormone replacement therapy (HRT) medication is being rationed, with women being warned they could struggle to get hold of patches for nearly a year.
Health officials have summoned pharmaceutical bosses for urgent meetings next week after it emerged some women have been forced to fly abroad to secure the menopause-treating drugs.
Supplies of Evorel HRT patches, which have a 40 per cent market share, have faltered in recent weeks, and the company warned yesterday that stocks may run out completely in October.
Meanwhile patches made by Theramex, such as Fem Seven Sequi and Conti, have been out of stock for months and will not be available until 2020.
The shortage has forced Novartis, which makes Estradot patches, to ration their stock in the UK so they do not all sell out at once due to the increased demand.
Janssen, which makes the Evorel range, said it had seen more demand in the UK already this year than the whole of 2018.
The problem is thought to have started last year when Theramex stopped production because of issues manufacturing the glue for their patches, which are made in China, forcing customers towards other brands.
Around one in ten women going through the menopause are prescribed HRT, amounting to approximately 200,000 women in the UK.
It is thought that around two-thirds of HRT treatments have been hit by the shortages.
Janssen said it may not return to full supply until the middle of 2020.
One NHS consultant gynaecologist said patients have been flying to Spain to by Everol over the counter.
“It is now impossible to get patches - it is virtually impossible to fun a clinic,” said Dr Anne Henderson.
“Women are getting desperate, they are left with no other option than to look overseas,” she told the Daily Mail.
The shortages have prompted fears that women are turning to buying potentially counterfeit HRT drugs online.
HRT relieves symptoms of the menopause by replacing the hormones that the body has stopped producing.
Without them, many women suffer symptoms such as hot flushes and night sweats.
The drugs can be taken in the form of tablets, skin patches, creams and gels.
A spokesman for Janssen said: "The situation in Europe has evolved rapidly over recent months and continues to do so, impacting several manufacturers, including Janssen.
"We continue to experience an unprecedented increase in demand for the Evorel range of products, due in part to the lack of availability of alternative hormone replacement therapies not produced by Janssen."
He added: “We understand the urgency of the situation and have already taken steps to prolong continuity of supply for as long as possible, including diverting as much Evorel stock as possible to the UK from countries where demand is not as high.”
The supply problems are believed to have been exacerbated by new rules introduced in February by the European Medicines Agency designed to prevent medication being tampered with which forced manufacturers to alter their production lines.
A spokesman for the Department of Health and Social Care, said patients should discuss alternatives to their normal HRT products with their doctor.
“We know how distressing this shortage is for patients and it is our priority to ensure they can access the medicines they need.
“We continue to monitor this situation extremely closely and are taking urgent action to resolve these manufacturing issues with suppliers as quickly as possible.
“We have not restricted supplies of HRT, but support Novartis’s decision to manage demand to maintain the flow of existing stock.”