Thai authorities are tightening restrictions on the drug etomidate to curb its use in potentially deadly vape products known as “zombie pods”.

Currently, the anaesthetic etomidate is regulated as a specially controlled substance, and can be used only by doctors in medical centres for specific procedures or operations.

In several recent cases, however, the anaesthetic has been found mixed with liquid for e-cigarettes, according to the Food and Drug Administration (FDA).

The use of “zombie pods” that can lead to addiction among vape users is prevalent in China, Hong Kong and Taiwan, and is rising in Thailand, the FDA said on Thursday.

To prevent more dangerous cases, etomidate will be listed as a Psychotropic Substance Category 2, effective from July 27.

Illegal possession carries penalties of up to seven years in prison and/or up to 700,000 baht in fines. Sellers can face up to 15 years in prison and/or up to 1.5 million baht in fines.