The UK will leave the European Union at the strike of 11pm on January 31.
A “transition period” will ensure “business as usual” until the end of 2020.
During this time, politicians will be busy negotiating trade deals - including the licensing and regulation of drugs manufactured in the EU and shipped to the UK.
While many need antibiotics or prescribed painkillers as a “one-off”, millions rely on repeat medication to control everything from diabetes to asthma.
How could Brexit threaten prescriptions?
During the transition period, the UK will continue to follow all of the EU’s rules and maintain trading arrangements.
“Trade in products between the UK and the EU will not change, so medicines supply will not be affected”, Professor Tamara Hervey, professor of EU law at the University of Sheffield, told Yahoo UK.
The transition period is needed while a free trade agreement is negotiated, which would allow goods - including drugs - to move around the EU without checks or additional fees.
If an arrangement cannot be settled in these 11 months, it will be “no deal”.
“If there is no agreement at that time, we can expect disruption to medicines supply,” Professor Hervey said.
“The supply of medicines is one sector where distribution chains involve multiple border crossings, which rely on EU law for 'frictionless' trade.
“If new paperwork is needed, there will logically be increased costs associated.”
The main channel crossing between the UK and France is feared to be worse affected, with three quarters of medicines arriving via this route, The BMJ reported.
Writing in a public letter on December 7 2018, secretary of state for health and social care Matt Hancock said: “The European Commission has made it clear that, in the event of a ‘no deal’ scenario, it will impose full third country controls on people and goods entering the EU from the UK.
“Whether this happens or not is in their hands, not ours.”
Even while in the EU, medicine supply and transportation to the UK and other member states was complex.
“As things stand, the process is a finely balanced one”, Ash Soni, president of the Royal Pharmaceutical Society, wrote in The Guardian.
“At each step things can, and sometimes do, go wrong.”
Medicines can be discarded due to a risk of contamination or transport containers overheating.
These issues “pale into insignificance compared to the problems Brexit has the potential to create”, Mr Soni wrote.
The UK reportedly does not have the “manufacturing capacity” to meet the country’s medicine demand.
Increasing capacity would take time, with facilities first having to be approved for safety and efficacy.
“Longer term, it might be new medicines are launched later in the UK, if the UK requires different regulatory standards to the EU's, because the EU is a much bigger market for launch of a new medicine,” Professor Hervey said.
What is the government doing to ensure medicines reach the UK after Brexit?
On August 23 2018, Hancock reportedly contacted “all pharmaceutical companies that supply prescription-only medicines and pharmacy medicines to the UK from, or via, the European Union or European Economic Area”.
The secretary of state asked the companies to “ensure they have a minimum of six weeks additional supply in the UK, over and above existing business-as-usual buffer stocks, by 29 March 2019”.
The Royal Pharmaceutical Society reported the department of health and social care (DHSC) asked these extra stocks to be in the UK by April 29 last year.
On February 26 last year, The Pharmaceutical Journal wrote how the government has “identified 7,000 medicines” that need to be “stockpiled” for a “six week buffer”.
This is out of the 12,300 licensed drugs used in the UK.
For medicines with a short shelf-life - like EpiPens - the DHSC has arranged a “freight service” to ensure they can be flown in “quickly” if a no-deal goes ahead.
The “Express Freight Service” will run on a “24-hour basis and a two-to-four-day pallet delivery service”.
The government has also arranged extra warehouse space, including refrigerated storage, to hold “buffer” stock.
It also has extra shipping in place on a “variety of routes” to “ease pressure on the short straits crossings to Dover and Folkestone”.
Medicines will be prioritised on these routes.
If a patient is left without a prescription, the Serious Shortage Protocol could come into play.
This allows pharmacists to dispense a suitable alternative, rather than sending the patient back to their doctor.
Not all drugs are eligible, however, for example those used to treat epilepsy.
While a deal is negotiated, patients and pharmacies alike are urged not to stockpile medicine.
“The Government has plans in place to ensure a continued supply of medicines to patients from the moment we leave the EU,” Hancock previously said.
“Any incidences involving the over ordering of medicines will be investigated and followed up with the relevant chief or responsible pharmacist directly”.
A patient’s prescription is subject to change according to how their condition progresses.
Stockpiled medicines may no longer be needed and have to be discarded, going to waste.
They also deprive others who need the same drug, creating a stockpiling issue in itself.
Health minister Stephen Hammond previously said there is no “hard evidence” Brexit will cause medicine shortages.
“While we never give guarantees, we are confident that, if everyone - including suppliers, freight companies, international partners and the health and care system - does what they need to do, the supply of medicines and medical products should be uninterrupted in the event of exiting the EU without a deal,” he said.
If a no-deal occurs, the UK will “push member states hard to introduce pragmatic arrangements to ensure the continued full flow of goods which would be to their benefit as well as ours”, Hancock added.