Guanoxan is a

sympatholytic A sympatholytic (sympathoplegic) drug is a medication that opposes the downstream effects of postganglionic nerve firing in effector organs innervated by the sympathetic nervous system (SNS). They are indicated for various functions; for example, t ...

drug that was marketed as Envacar by Pfizer in the UK to treat

high blood pressure Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...

. It was not widely used and was eventually withdrawn from the market due to liver toxicity.

References

Adrenergic release inhibitors Benzodioxans Guanidines Hepatotoxins Withdrawn drugs {{antihypertensive-stub