Addiction psychiatrist Dr Colin O'Gara believes that social media sites have "opened the door" for prescription drug dealers to thrive.
Dr O'Gara, the clinical lead for addiction services at St John of God Hospital, Dublin, said it is now easier to buy narcotics online than ever before.
"In previous times it would mainly be young, computer-savvy people that would use the internet to purchase drugs," he said.
"We've noticed that this is not the case any more.
"All age groups are doing it now, as sites such as Facebook have made these addictive meds easier to find and buy.
"Over the past five years we've seen a steady increase in the number of people who are seeking help, especially for opioid addiction.
"This would most likely be due to how accessible they've become over the internet."
Dr O'Gara said patients became addicted to powerful pain relief drugs for different reasons.
"Using codeine-based products and other opioids for genuine pain relief purposes may sometimes lead to people taking increased amounts, which can often start the addiction cycle," he said.
"Sometimes it's so severe people need to be substituted on to heavier drugs like methadone or morphine.
Dr O'Gara added that Ireland is now seeing the introduction of Fentanyl, a powerful opioid painkiller and anaesthetic that has caused chaos in the US.
"The Fentanyl crisis has got so bad over there that the government has declared a state of emergency," he said.
"Heroin is powerful and people die of overdoses all the time, but when I read that Fentanyl is about 50 times stronger, I just couldn't believe it.
"It's very small and easy to package and conceal, so you can imagine the international profit these drug dealers and manufacturers are making.
"Fentanyl and other opioids would definitely be a significant concern for us going into the future."
Dr O'Gara's service offers a range of different treatment programmes for people suffering from addiction.
"We have an in-patient rehabilitation programme for prescription drug abusers - that would be a 28-day programme," he said.
"We would do a stabilisation period, so if someone is taking 50 tablets a day we would look at getting them on to controlled doses of either benzo or opioid medication, then reducing it down.
"The next step is detoxing, along with rehab."
For more information about the Stillorgan-based facility, visit stjohnofgodhospital.ie.