We don't have synonyms for atropin yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are tropin and atropia.
(n) :
Alternative spelling of atropine. [(toxicology, pharmacology) An alkaloid extracted from the plant deadly nightshade (Atropa belladonna) and other sources, such as the seeds of the thorn-apple. Though overdoses would be fatal it is used as a drug in medicine for its paralytic effects (e.g. in surgery to relax muscles, in dentistry to dry the mouth, in ophthalmology to dilate the pupils).]
(n) :
Alternative spelling of atropine. [(toxicology, pharmacology) An alkaloid extracted from the plant deadly nightshade (Atropa belladonna) and other sources, such as the seeds of the thorn-apple. Though overdoses would be fatal it is used as a drug in medicine for its paralytic effects (e.g. in surgery to relax muscles, in dentistry to dry the mouth, in ophthalmology to dilate the pupils).]