During my pediatric rotation I worked with a CRNA that routinely uses a combination of neostigmine and physostigmine for older children & adolescents. She calculates her normal neostigmine reversal dose but only gives 2/3 of it and the other 1/3 as physostigmine. For example, a 40kg pt may require 2.4mg of neostigmine but she only gives 1.6mg while giving the other 0.8mg as physostigmine. She states that these patients wake up "smoother" than those receiving just neostigmine but has no solid reasoning for doing so. Apparently she learned this from her preceptor many years ago. I understand that physostigmine has a tertiary amino group that passes the blood brain barrier but this patient population doesn't necessarily receive any anticholinergic that passes the barrier (e.g. Atropine).
