Benzhexol (Artane)

Benzhexol (also called trihexyphenidyl, brand name Artane) is a medicine legitimately prescribed to manage the movement side effects caused by antipsychotic drugs. On the street it is known as "Cosmos" or "Bugizi." It is the second most abused prescription medicine in Kenya.

When taken in doses far higher than prescribed, benzhexol produces hallucinations, euphoria, and a dissociative, dream-like state. It is this effect that drives its abuse, particularly among polydrug users who use it to enhance the effects of heroin, khat, or alcohol.

It is obtained cheaply on the black market and is widely available in informal markets in Nairobi, Mombasa, and other urban centres. It is sometimes sold alongside heroin to enhance the experience of using.

Users report that benzhexol produces vivid, detailed hallucinations at high doses, which some find intensely pleasurable or entertaining. This effect is the primary reason for its recreational use.

It is combined with heroin to intensify and modify the opioid high. The combination of anticholinergic hallucinations and opioid sedation creates an experience users describe as uniquely intense.

Cost and accessibility drive use. Benzhexol is very cheap and widely available without a prescription in informal markets.

Benzhexol produces psychological rather than physical dependence. However, the hallucinogenic experience can become strongly sought after, and the tolerance that develops drives escalating use.

Anticholinergic toxicity from high doses is medically dangerous and can be fatal. The margin between a recreational dose and a toxic dose is narrow.

Polydrug users, particularly heroin users in Nairobi and coastal Kenya, are the most commonly identified group. Benzhexol is used as an add-on to heroin to intensify the experience.

Young people in urban informal settlements use it as a standalone hallucinogen. The street name "Cosmos" suggests its use as a means of escaping immediate reality.

People with severe mental illness who are prescribed it legitimately may be targets for theft or trading of their medication.

The 2026 NACADA wastewater analysis identified benzhexol (trihexyphenidyl) as the second most detected prescription drug of abuse at 24%, detected across multiple counties.

Nation Africa documented its street name "Cosmos" and its use specifically to enhance heroin: "I top my dose of heroin with cosmos to feel high" (user testimony, 2023).

The easy availability of benzhexol on the black market creates a particular problem: it is prescribed legitimately to people on antipsychotics, and diversions from this supply feed street availability.

NACADA has flagged benzhexol as one of the most dangerous prescription drug misuse patterns because of the risk of acute anticholinergic toxicity and the fact that many users do not recognise overdose symptoms.