Detectives have now appealed for information about the robbery, which happened yesterday (August 3) at Health Pharmacy Ltd in Free School Lane, Halifax.
The knife-wielding man went into the pharmacy at about 2.15pm and made demands for the drugs, which were stored in locked cabinets. He then left on foot.
He is described as Asian, about 5ft 8ins and of large build, which could be due to him wearing extra clothes. His clothing is described as traditional Asian dress, dark in colour, with a brown, chequered scarf covering his head and face.
“We would urge anyone offered such drugs to report it to the police as a matter of urgency.
“We would also like to hear from anyone who saw a male matching the suspect’s description in the Savile Park area around the time of this robbery or with any other information that could help our ongoing investigation.”
Information can be passed to Calderdale District CID via 101, quoting crime reference 13180384088, or by using the 101 Live Chat facility on the West Yorkshire Police website.
Alternatively, information can be given anonymously to independent charity Crimestoppers on 0800 555 111.
Staff were left distressed by the robbery, with a spokesperson saying on Facebook that they were "unharmed but quite shaken up".