As Greece is facing shortages of prescription drugs sold to other countries, port authorities said they confiscated 3.75 million capsules of Nervigesic Pregabalin, in 500 cartons weighing 3.14 tons from a United Kingdom-flagged vessel at the port of Lavrio.

The Coast Guard said the ship was found and boarded after they received information from the National Intelligence Service (EYP) on the activity of Egyptian crime gangs active in Greece. It wasn’t said if Greece was the final destination.

The drug, which is used to treat nerve pain, epilepsy and anxiety, can bring about an elevated mood in users but can also have serious side effects, particularly when used in combination with other drugs, according to the UK Home Office, which reclassified pregabalin as class C controlled substance in October 2018.

In some jurisdictions, pregabalin is banned because it can be used as a heroin substitute. A prosecutor ordered the sealing of the vessel while port officials continue their investigation.