The following persons need not register and may lawfully possess dangerous drugs under this chapter:
(1) an agent or employee of any registered manufacturer, distributor, or dispenser of any dangerous drug if the agent or employee is acting in the usual course of business or employment;
(2) a common or contract carrier or warehouse operator or an employee of the carrier or warehouse operator, whose possession of any dangerous drug is in the usual course of business or employment;
(3) an ultimate user or a person in possession of any dangerous drug pursuant to a lawful order of a practitioner or in lawful possession of a Schedule V drug;
(4) officers and employees of the state, or a political subdivision of the state while acting in the course of their official duties.