Almost 100 people in Cavan and Monaghan received opioid-substitution treatment in the first six months of this year.
In the vast majority of cases, this is used to treat heroin addiction.
70 men and 28 women were prescribed methadone and other opioid-replacement drugs in pharmacies since January.
Nationally, more than 7,600 people were treated in the first half of the year, the majority being men.
Local figures are close to reaching what was seen in the full twelve months of 2018
Last year, 116 people were treated locally, with 104 in 2017.