The Health Research Board has reported a steady increase in the number of people being treated for and dying from sedative misuse.
Drugs known as benzodizepines are prescribed to treat anxiety, insomnia and other conditions and there has been an increase in use by over 63% from 1,054 cases in 2003 to 1,719 cases in 2008.
These prescription drugs were also implicated in nearly one third of all deaths by drug poisoning between 1998 and 2007.
The annual number of deaths rose from 65 in 1998 to 88 deaths in 2007.
Dr Suzi Lyons, senior researcher at the HRB, said that while benzodiazepines are considered safe for short term use, the risk of overuse, abuse, and dependence is well documented.
She said doctors need to be more aware of the potentially fatal effects of these sedatives when used with other substances, such as alcohol or opiates.
The increase use may be due to several factors, such as more treatment places, an increase in use in the population, and more centres reporting to the HRB's national drug treatment reporting system.
Twice as many men died as a result of misuse of benzodiazepines than women.
An overdose of benzodiazepines can cause respiratory depression, coma and death.