When haloperidol is administered as a depot injection, which of the following is most accurate regarding its pharmacological effect?

• A. It results in immediate peak plasma levels and rapid clearance from the body.
• B. It requires daily administration to maintain therapeutic levels.
• C. It provides a slow and sustained release of the medication over several weeks.
• D. It is less effective than oral haloperidol in treating psychotic symptoms.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of depot injections in pharmacology. Depot injections are formulated to release medication slowly over an extended period, maintaining therapeutic drug levels without frequent dosing.
2. Step 2: Recognize that haloperidol, when given as a depot injection, is designed to avoid immediate peak plasma levels, which are typical of oral or intravenous administration.
3. Step 3: Consider the pharmacokinetics of depot haloperidol: it bypasses the need for daily administration by providing a slow and sustained release of the drug, which helps maintain stable plasma concentrations.
4. Step 4: Compare the effectiveness of depot haloperidol with oral haloperidol. Depot injections are generally as effective, if not more, due to improved adherence and steady drug levels, rather than being less effective.
5. Step 5: Conclude that the most accurate statement is that depot haloperidol provides a slow and sustained release of the medication over several weeks, which aligns with its pharmacological purpose.