Final answer:
Exempt narcotics can be sold up to a certain number of dosage units without a prescription in a 72-hour period. This limit ensures safe consumption of over-the-counter medications, considering their different half-lives and associated risks.
Step-by-step explanation:
Exempt narcotics are regulated under the Controlled Substances Act, which specifies how many dosage units of certain over-the-counter medications can be sold without a prescription. Individuals are allowed to purchase a limited number of dosage units within a certain time frame to prevent abuse. Specifically, the correct answer to your question is C) 72-hour period. According to the law, a customer may not acquire more than a set number of dosage units of exempt narcotics within a 72-hour period without a prescription.
It is important to understand that different drugs have varying half-lives, which influence the appropriate dosing interval and the amount that can be safely consumed. Drugs with shorter half-lives may require more frequent dosing, while drugs with longer half-lives can often be taken less frequently but may pose risks if the drug levels remain toxic for a longer period. The regulation is in place to ensure safety by limiting access without a prescription, given these pharmacological considerations.