Robert Adams first describes the cardiac condition which will become known as Adams-Stokes syndrome.

Adams-Stokes syndrome is a cardiac syncope which may occur with seizures caused by complete or incomplete heart block.

However, the injection of antimony potassium tartrate had severe side effects such as Adams-Stokes syndrome and therefore alternative substances were under investigation.

You should not use this medication if you are allergic to fosphenytoin or phenytoin (Dilantin) or if you have certain heart conditions such as slow heartbeats, heart block, AV block, or Adams-Stokes syndrome (a heart rhythm disorder).