Concept:
Sustained release dosage forms are designed to release drug slowly over an extended period.
Step 1: Requirement of the question.
The question mentions prolonged action. This means the drug should remain effective for a longer duration.
Step 2: Role of sustained release tablets.
Sustained release tablets maintain drug concentration for a longer time and reduce frequent dosing.
Step 3: Low dose variation.
Controlled release from the tablet helps avoid sudden peaks and troughs in drug level.
Step 4: Final answer.
Therefore, the drug should be formulated as a sustained release tablet.
\[
\boxed{\text{Sustained release tablet}}
\]