According to the website www.drugs.com, GHB is a central nervous system depressant that is commonly referred to as a "club drug" or "date rape" drug.
Euphoria, increased sex drive, and tranquillity are reported positive effects of using GHB. However, immediate negative effects may include sweating, loss of consciousness, nausea, auditory and visual hallucinations, headaches, vomiting, exhaustion, sluggishness, amnesia, confusion, and clumsiness.
A Fire Service spokesman said its staff had assisted paramedics in lifting two people from the club.
A woman answering phones at the club said she had no comment.
Femme Fatale advertises itself as "New Zealand's #1 Gentlemans Club".