This inhibition leads to a buildup of acetaldehyde, causing an alcohol flush reaction.

[6][7][8] Symptoms of coprine poisoning include facial reddening/flushing, nausea, vomiting, malaise, agitation, palpitations, tingling in limbs, and sometimes headache and excessive salivation.

[5] In examining coprine poisoning cases in Germany in 2010, none of the patients died, and all made full recoveries after abstaining from alcohol.

[12] Coprine hydrolyzes to glutamic acid and 1-aminocyclopropanol, which inhibits the enzyme aldehyde dehydrogenase.

[11] 1-aminocyclopropanol quickly converts to cyclopropanone hydrate, which binds covalently to the thiol group present in the enzyme, deactivating the dehydrogenase activity.

However, as shown in the mechanism below, the covalent bonding is reversible, which is what allows symptoms to subside if no more alcohol is consumed.

Adding sodium hydroxide to create 1-aminocyclopropanol will destabilize the structure, so synthesis must be conducted using the hydrochloride.