anticholinergic

https://doi.org/10.1351/goldbook.A00385
  1. (adjective). Preventing transmission of parasympathetic nerve impulses.
  2. (noun). Substance which prevents transmission of parasympathetic nerve impulses.
Source:
PAC, 1993, 65, 2003. 'Glossary for chemists of terms used in toxicology (IUPAC Recommendations 1993)' on page 2014 (https://doi.org/10.1351/pac199365092003)