The street drug ecstasy that was responsible for five recent Calgary-area overdose deaths was laced with other, more potent compounds, according to toxicology results.

Ecstasy laced with other drugs, including methamphetamine, has been found by toxicology tests to have been ingested by five recent overdose fatality victims. Calgary police showed this ecstasy Wednesday at a news conference. (CBC)

Paramethoxymethamphetamine (PMMA) and methamphetamine were present in the lab results for each of the recent deaths, the chief medical examiner's office said.

Officials believe each of the overdose victims thought they were taking straight ecstasy (MDMA).

"This is a prime example of the gamble people take when they use illegal drugs," said Calgary police drug unit staff Sgt. Mike Bossley.

"You never know what is in your drug: yesterday, it was MDMA, today, it’s PMMA, and tomorrow, it could be something else. There is no safe street drug, and no safe dose of a street drug," he said.

Dr. Mark Yarema, medical director of the province’s Poison and Drug Information Service (PADIS), said while they can look similar, there are important differences between ecstasy and methamphetamine.

"Although all have toxic effects, PMMA is considered more toxic than MDMA, with a higher incidence of seizures and elevated body temperature."

Methamphetamine can also be slower to act, prompting users to take several tablets to get the desired effect, he said.

Police are still investigating the source of the drugs taken in each of the deaths. The names of the victims are not being released for privacy reasons.