On a Saturday night this past March, Melissa Sheldrick gave her eight-year-old son Andrew his usual liquid medication for his REM sleep disorder and then tucked him into bed.

When she went to wake him in the morning, her little boy was dead.

It’s a nightmare almost too painful to even imagine. It would take almost five months before she and her husband, Alan, learned what killed their only son: The coroner sat them down and told them their healthy child had died from a lethal dose of baclofen, a powerful muscle relaxant usually used to treat adults with MS.

Andrew hadn’t been prescribed baclofen.

Floradale Medical Pharmacy in Mississauga had refilled their son’s prescription the day before for his usual tryptophan. But according to the family’s $4-million lawsuit filed this week, “an analysis of the tryptophan medication compounded by Floradale revealed that it contained 135 mg of baclofen and no trace of tryptophan. This indicates that baclofen was substituted for tryptophan at Floradale in error.”

A request for comment from Floradale owner Amit Shah was not returned. No statement of defence has yet been filed and the family’s allegations have not been tested in court.

In their grief, the Sheldricks have launched more than just a lawsuit. They’ve started a petition calling on Queen’s Park to force pharmacies to report any medication errors so they can be tracked not only for consumers, but so any trends can be identified and corrected.

Shockingly, as it stands right now, any mistake can be kept quiet. Incorrect dosages, inadvertent medication substitutions, misread prescriptions — the Ontario College of Pharmacists doesn’t require their members to report any of them. Only Nova Scotia makes it mandatory to report all medication errors and near-misses to the Institute for Safe Medication Practices (ISMP) Canada — in its first three years, the province had a frightening 75,000 reported incidents.

According to the ISMP, dispensing slip-ups are rare — yet the non-profit group, which depends mostly on voluntary reports, admits it has no official data for this country. In the U.S., the accuracy rate is estimated at 98.3%. “Canadian researchers have estimated that extrapolating this data to Canada would have resulted in 7 million medication errors in 2009, based on 453 million prescriptions dispensed in Canada in 2008,” says spokesman Julie Greenall.

That’s a stunning number of errors. The ISMP estimates that only 1% of the cases reported to them have resulted in patient harm. For Sheldrick, that harm saw her family of four tragically reduced to three. “He was a light and this has left a huge, gaping hole in our lives,” his mother says.

Like most of us, Sheldrick never imagined such a medication mix-up could even occur. When her son had trouble swallowing his pills, they were referred to a compound pharmacy that would produce a mixture instead. For 18 months, there had been no problems — until that fatal refill.

When the coroner told them the cause of their son’s death, they were stunned — and then they were furious. What made it worse was realizing that no one would learn from their excruciating experience — not the public and not other pharmacies.

“How does this happen?” demands his mother. “This is so unbelievable and so unacceptable. We don’t want anyone to have to go through what we have. Pharmacies have to be accountable for their errors.”

She has garnered more than 2,000 signatures on her petition : “Nothing can bring Andrew back to us, however, in his caring spirit we want the laws to protect all people, and so we are asking that Ontario create a law to enforce the use of error tracking tools for dispensaries,” Sheldrick wrote on the change.org site.

“Thousands of pharmacy errors are made annually, but there is no law in Ontario requiring such errors to be reported or tracked. A reporting system would help put in place a vehicle to examine errors and see how training and procedures can be improved to reduce the number and types of errors.”

For a family left broken, such a law is the only good they can imagine coming from their loss.