pyridostigmine UK /ˌpɪ.ɹɪ.dəʊˈstɪɡ.miːn/US /ˌpɪɹ.ɪ.doʊˈstɪɡˌmin/ noun1 •A parasympathomimetic and reversible cholinesterase inhibitor, used to treat muscle weakness and to combat the effects of curariform drug toxicity.