The Irish Prison Service has said it is working with the HSE after “a number of overdose presentations in custody at Midlands Prison” yesterday.
Four prisoners were hospitalised as a result of overdoses, after drugs were dropped by drone into a prison yard.
“A drone dropped drugs into D yard on Friday,” a source told RTÉ News.
“Six prisoners overdosed, four were taken to hospital and one remains in hospital in an induced coma,” the source added.
Earlier, the prison service said staff have increased the use of “random and intelligence-led cell searches on a daily basis”.
In a statement, the service said its canine unit is carrying out searches around the prisons, “including a greater focus on searching deliveries into prisons”.
“The Irish Prison Service continues to engage with An Garda Síochána with regard to preventing contraband entering our prison and this happens at both local and national level.”
The service said it is working closely with colleagues in An Garda Síochána “on a regular basis and the sharing of intelligence has led to target searches resulting in the seizure of contraband”.
It added that “extra vigilance” is being taken and stopping contraband and drugs from entering the prison “continues to be a high priority”.
The prison service has also appealed to prisoners, visitors, staff or members of the public with information regarding the trafficking of contraband to contact them.
There is a free confidential telephone line (1800 855 717) and text line (086 180 2449) which is operational.