According to the authority’s statement, there is an investigation running “to check all phases of the circulation of medicines”.

Some 430 units of Fentanilo Basi injectable solution 0.05 mg/ml ampoule – 10 units – 5 ml, serial number 4419685, batch 2022, vanished from a wholesale distributor.

Infarmed also asked people to inform them of any suspicion about the authenticity of these units, because “it is possible they have been introduced in the legal market”.

Fentanyl, also spelled fentanil, is an opioid 50 times more powerful than heroin.

It is used as pain medication, for example for cancer and chronic pain, and together with other medications for anaesthesia.