The Irish pharmaceutical industry has urged patients and pharmacists not to stockpile medicines in advance of Brexit.
Oliver O'Connor, Chief Executive of the Irish Pharmaceutical Healthcare Association, said thousands of medicines were involved in the health system and the supply chain was really delicate.
He said the industry had been working for the last two years to ensure continuity of supply and it had prepared for all possible Brexit scenarios.
Mr O'Connor said it wasimportant that patients and pharmacists do not take things into their own hands and start buying up stocks of new medicines.
According to the association, up to 70% of medicines on the Irish market either come from or transit the UK.
The impact of Brexit on the Irish health system remains uncertain.
Key issues are the supply of medicines, cross-border healthcare, Irish patients accessing treatment in Britain under the EU Treatment Abroad Scheme and the future recruitment of doctors and nurses from the UK.
Professor Anthony Staines, of the Department of Nursing and Human Sciences at Dublin City University, said that mutual recognition of qualifications may be an issue in the future.
He said Ireland and Britain are currently part of the same system but after Brexit, the UK becomes a third country.
He said that if people already have a recognised health qualification they are fine, but if they acquire a qualification after Brexit they are not fine and a system will have to be established to manage this.
Prof Staines also said the future of cross-border and cardiac care between the Republic and Northern Ireland was uncertain.
The Health Service Executive said it was working on contingency plans in a number of areas.
It also said it did not anticipate any interruption to organ donation and transplant services after Brexit.
Minister for Health Simon Harris is due to brief the Cabinet next week on the Brexit implications for the health service, in particular for medicines.