Urgent action is needed to stem shortages of some medicines in the UK as drug wholesalers look to export stocks to profit from the weak pound, it has been warned.
The Royal Pharmaceutical Society of Great Britain (RPSGB) said the issue of medicine availability needed to be addressed quickly or risked harming patients' health.
The Government is understood to be preparing a summit next month to seek a resolution to the current problems.
According to the RPSGB, more than 40 well-known medicines for chronic conditions are in short supply, with pharmacists reporting notable shortages.
They include anti-hypertensives, epilepsy treatments, plus some medicines to treat cancer and prevent rejection following organ transplantation.
The RPSGB said the weak pound in relation to the euro had increased the demand for UK-sourced medicines, while the supply of medicines from other EU states dwindled with their rising cost.
In turn, exports of UK-sourced medicines into Europe had increased in line with their competitive prices.
Neal Patel, pharmacist and RPSGB spokesman, said: "The reason for the Society taking this action is our concern for patients who may not get the treatment they need at the time they need it. Our members are spending long hours chasing down supplies which are increasingly difficult to obtain.
"It's through the hard work of pharmacists that patient supplies are being maintained.
"The Society fears that if we do not identify a solution through real understanding of the problem, then patient care will continue to suffer.
"We will be attending the summit recently announced by ministers where we hope solutions will be found to ensure that UK medicines supply is maintained at the appropriate level to guarantee patient care."
Health Minister Mike O'Brien labelled those putting profits before patients "unscrupulous".
He said: "For months I have been concerned about the potential impact on patients' health of a small number of medicines being sold abroad by speculators. It is unacceptable that people have had to wait longer than they should have to get their medication.
"I have made it very clear that it is a very few unscrupulous people that are putting profits before patients. Rather than selling drugs to NHS patients as they should, they are selling them abroad for greater profit.
"I am pleased that the different parts of the supply chain have come together to work with the Government to tackle this and the joint guidance we have already developed makes clear the legal and ethical duties on the supply chain as well as their consequences.
"The Government believes that this spirit of collaboration is the best way to further minimise the risks to patients. That is why the Secretary of State and I have called a summit in early March with all those organisations involved in the supply of medicines to better understand the issues involved and what might be done to address them."