Police say there has been a further four spiking incidents in the Belfast area.
Detailed investigations are underway into each of the cases, including a review of CCTV footage and the deployment of early evidence kits.
Police are stepping up their presence and visibility in the city centre area and want to reassure the public.
The PSNI has issued a warning to perpetrators that investigating these reported crimes is a priority and all avenues of enquiry are being explored.
Chief Inspector Fox said police have been working with the hospitality sector to provide up to date advice and guidance around enhancing crime prevention measures that will ensure the safety of everyone.
“We are stepping up our visibility and presence in the city centre and our frontline early evidence kits and procedures are enabling officers to respond to and investigate these incidents appropriately and quickly. I would urge anyone who thinks they have been spiked to contact police as soon as possible so that we can maximise all investigative opportunities.
“Any perpetrator who thinks they can get away with these despicable acts should be left in no doubt that police are leaving no stone unturned in our efforts to investigate and apprehend them,” added the Chief Inspector.