Nurses need help dealing with women who have been drug-raped, experts say.
Nurses are seeing more cases of drug-rape
Senior nursing strategist Dave Dawes said women were increasingly going to A&E units and sexual health clinics after such attacks.
He told the Royal College of Nursing conference nurses needed clear guidance and training on how to spot drug-rape cases and liaise with police.
Police deal with about 500 cases of drug-rape a year but the true extent of the crime is thought to be much higher.
Experts say many women do not report cases because the drugs, most cases involve GHB or Rohypnol, can leave them unsure of what has happened.
Mr Dawes, part of the RCN's body for nurses in senior management, said: "Women are turning up, not quite knowing what has happened to them and the problem is nurses have not been properly trained in how to deal with such cases.
"It is easy to think the women have just had too much to drink. What we need is clear advice on how to recognise cases, when to contact police and what else should be done.
"One of the things is that the drugs leave the person's body very quickly so if evidence is to be gathered nurses have to act quickly."
He said information about drug-rape should be included in nurse training or guidance be issued advising nurses how to deal with cases.
Mr Dawes said he did not have any figures on how many cases nurses were seeing, but he heard anecdotally that it was on the increase.
According to national figures, more than 60% of spiking takes place in pubs and clubs, and victims are most likely to be women aged between 18 and 30.
Experts say that unlike the effects of alcohol, which are gradual, a spiked drink will generally cause sudden dizziness, nausea, vomiting, uninhibited feelings and memory loss.
They say victims are left extremely vulnerable and at risk of sex attacks.