E-Surgery has compiled a list of 59 drugs which could be difficult or even impossible for patients to access in the event of the UK leaving the EU without an agreement, reported Belfast Telegraph.
The online pharmacy said at-risk drugs include allopurinol, which is used to treat high uric acid in patients undergoing chemotherapy, the brat cancer drug exemestane, type 2 diabetes medication metformin, and olanzapine, an anti-psychotic.
According to the news source, a range of medications to control hypertension also feature on the list, as do a number of treatments to alleviate the symptoms of Parkinson's disease.
E-Surgery also warned there may be problems with the supply of a number of antidepressants, including nortriptyline, sertraline and venlafaxine.
Oskar Wendowski, chief executive at E-Surgery, said the list was based on information provided by pharmaceutical companies that supply medication to pharmacies across the UK.
"We can share with you the following medications which our suppliers have expressed concern about, either because there are worries around future import rights or because the prices are already rising as a result of stockpiling, leading to real concerns over post-Brexit costs and availability," he said.