Toronto police have issued a public safety alert after at least five people showed signs of suspected drug overdoses at downtown nightclubs, including one that ended in a fatality.

According to police, officers responded to a medical complaint around 12:42 a.m. at Uniun nightclub in downtown Toronto after a woman reportedly collapsed from an apparent drug overdose. The woman was rushed to the hospital where she was later pronounced dead.

While investigating the incident, police say another woman also collapsed from a suspected overdose at the same nightclub. She was taken to the hospital in serious condition.

Shortly after, around 1:30 a.m., officers say they responded to medical complaint at Rebel nightclub involving two men and a woman who had also collapsed from apparent drug overdoses. All three were taken to the hospital.

Police suspect the overdoses may have involved the drug MDMA, which is also known as ecstasy. According to Health Canada, MDMA can cause hallucinations, paranoia and an increased heart rate.