The driver, 34-year-old Warawut Kulphan, from Takua Tung in Phang Nga was stopped after he was “seen acting suspiciously”.
The pills were on the back seat, packed in a green plastic bag.
Wawarut admitted that he picked up the drugs, which were mailed to a house in Baan Promphan in Pa Khlok, and was taking them to distribute in the Karon area.
He was taken to to Thalang Police Station for further questioning on a charge of possession of restricted medicines without any permit.
Although Alprazolam, better known as Xanax, can be habit-forming, it is widely prescribed, legally, as an anti-anxiety, it is also popular in some circles as a recreational drug, either on its own or combined with other drugs. It is also used by methamphetamine addicts to allow them to sleep.