In brain, etomidate binds to and activate gamma-alpha butyric acid (GABA) receptor. This causes amnesia (forgetfulness), ataxia (unstable movement) and confusion. It further affects ‘wiring’ of a small part of the brain (hippocampus) and may retard brain development of young vapers. It also suppresses hormone and affects kidney and lung functions.
A question arises: why etomidate enters the brain readily?
The rate of distribution of drug to the brain (or other organs) is defined by its distribution half-life (T1/2).
T1/2 = ln2*Kpb/(Q/VT)
Where Kpb is brain-to-blood concentration of drug at distribution equilibrium and Q/VT is perfusion (volume of blood per volume of brain per unit time).
As brain is moderately-highly perfused at 0.5 mL/min per g of brain, the drug is fat soluble and Kpb is relatively low, the distribution half-life of etomidate is very short (2.7 min).
This explains why etomidate is used as an intravenous anesthetic drug in the hospital as it elicits sedation and pain-relief within a short time.
But when vaped, etomidate enters the brain fast and causes the adverse effects quickly.
Stop and quit vaping as we do not know if the illicit vape products are laced with etomidate, its chemical analogues or other undeclared pharmaceutical drugs!
Read also: Food-Drug Interactions on Drug Safety & Efficacy
Resource Person: Eric Chan, PhD