At least 19 health trusts in Britain have written to the department of health warning it of shortage of vital medicines to treat high blood pressure, asthma and Parkinson's disease, Indian-origin MP Keith Vaz has found.
The Daily Mail said there were concerns that drugs manufactured in Britain, meant for local patients, were being sold to European countries by wholesalers and pharmacists.
Fluctuations in exchange rates meant manufacturers can make more profit selling the drugs overseas, the daily said.
Although the practice is not illegal, the government has condemned it as unethical.
"The government must not wait until a patient loses their life due to the shortages to take action. I am worried that we are manufacturing medicines for this country and they are being sold abroad. It's shameful," Labour MP Vaz said.
Vaz said eight pharmacies in his constituency had contacted him about the problem during a single week.
The drugs currently in short supply include those to treat high blood pressure, cholesterol, asthma, diabetes, Parkinson's disease, osteoporosis, diabetes and depression.
The department of health said it was working with the medicine industry and wholesalers to minimise the impact of shortage.