The women, students at the same Australian National University college, attended the club on March 17.

"She went out for dinner with friends, had three, maybe four wines. She was tipsy but not drunk," the 18-year-old's mother said.

"A whole lot of them went off to Academy, she bought one drink, and she went from hero to zero in 15 minutes."

Stumbling but cared for by friends, the first-year uni student was put in a Uber and then bed. A week later she still had no memory of ever being at the club.

The second student told the 18-year-old she had also had her drink spiked, and was "vomiting and very unwell, and again has the memory wiped", the mother said.

There were no physical incidents involving either woman.

An ACT Policing spokesman said they were aware of an alleged drink spiking incident at a city nightclub, following information received by a female patron. No further details, including of any action taken, were provided.

"Police would encourage the public to be wary of possible drink spiking symptoms including sudden and rapid changes in people's behaviour and a deterioration in motor skills over a relatively short period," he said.

Academy owner Frank Condi said he was informed a man was questioned outside the club on the night in question, but he could not confirm if it was directly linked to the alleged incident or if the man was in the club that night.

"No one to my knowledge was charged, but I do not have that sort of information," he said.

"We do take all the allegations about drink spiking very seriously and will work with police to gather as much information as they need.

"At this stage police have not contacted us about the incident."

Alcohol is the most commonly used substance in drink spiking, followed by depressants such as GHB and Rohypnol, which change a person's behaviour and cause anything from a loss of inhibition to a loss of consciousness.

Perpetrators can often be invisible.

"Anecdotally I'm told some of these people are like pickpockets, you just wouldn't see it, and they target a heap of girls and hopefully one of them will stumble into the toilet or stumble into the streets, apparently that's how it works," the mother said.

"Girls also need to know how dangerous this is, not just what can happen to you by the perpetrator, but you can die in your sleep, the [drugs] are that powerful.

The 18-year-old's face became puffy and she was "almost unrecognisable" three days after the night out, but has had no lasting side effects.

Her nights out would involve bottled water – complete with lid – for some time, her mother said.

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