A father has written a heartfelt open letter about his teenage daughter's drug addiction in a bid to reverse a tide of substance abuse by young people in his home town.

Sean O'Leary, of Kanata, Ottowa, Canada, wrote the emotional Facebook missive after learning of the death of a 14-year-old girl from an apparent overdose and said the problem was now "indiscriminately taking our children’s lives".

He addressed other parents whose children use drugs—reportedly dangerous counterfeit prescription opioids—and added: "The days of the saying, 'They need to hit rock bottom before getting better' are over. Sadly in most cases today rock bottom is a slab at the morgue."

Speaking about his own 16-year-old daughter Paige, he said: "My first thought every morning is to check that Paige is alive. It is a nightmare of a way to live life especially when you have other children and have to try to make their lives as normal as possible.

"I have locked her at home, chased her around, grabbed her off the streets, walked in to people’s homes uninvited to take my daughter out of there, we have had paramedics and police to our home numerous times.

"But here we sit not knowing day to day whether our beautiful little girl will be alive tomorrow."

On her own Facebook page, Ms O'Leary urged her friends to read the letter.

Her father added: "My goal is not to try and solve the drug problem. It has been going on for many decades but never before right now have the drugs been indiscriminately taking our children’s lives.

"I do not know how many families are suffering the same fate as us right now but I know there are many."

He plans to set up a meeting for parents to learn how to keep their children safe and how to use opioid blocker medication. He knows of eight teens who have overdosed in the past two months in his town alone, he said.

Regional health officials have issued a warning about fake prescription drugs resembling the well-known Oxycontin and Percocet that have been cut with fentanyl, a highly potent synthetic opioid, which they said have been linked to life-threatening overdoses, CBC reported.