Kentucky LCADC Practice Test 2026 – Complete Exam Prep Guide

Substitution therapy relies on medications that act on the same opioid receptors to blunt withdrawal and cravings while stabilizing daily function. The classic agonist option is methadone. As a full mu-opioid receptor agonist, methadone activates these receptors to produce opioid effects, but with a long, steady action. This long half-life smooths out fluctuations from short-acting opioids, reduces withdrawal symptoms, and lowers cravings, which helps people stay in treatment and reduces illicit opioid use. Its pharmacokinetic profile—long duration and the ability to dose once daily—has made it a longstanding cornerstone of agonist replacement therapy, with extensive clinical experience supporting its effectiveness when used in supervised programs.

Naltrexone, by contrast, is an opioid antagonist; it blocks receptors and is used to prevent relapse after detox rather than to ease withdrawal. Buprenorphine is a partial agonist, offering some receptor activity but with ceiling effects that limit its potency and overdose risk; it’s also used in substitution therapy but functions differently from a full agonist like methadone. Disulfiram is not an opioid treatment at all; it’s used for alcohol use disorder to create an adverse reaction to alcohol.