Which form of phenytoin is a liquid preparation?

• A. Intravenous solution
• B. Tablet
• C. Chewable capsule
• D. Liquid suspension

Answer: (D)

The concept being tested is identifying which dosage form is a liquid preparation intended for oral use. Phenytoin is available in several forms, including solid tablets and chewable capsules, an oral liquid suspension, and an injectable intravenous solution. Among these, the oral liquid suspension is the true liquid preparation designed for oral administration. It consists of phenytoin particles dispersed in a liquid with suspending agents, meant to be shaken before dosing to ensure even distribution.

The oral suspension is used when a patient cannot swallow tablets or when precise liquid dosing is needed, especially in children. In contrast, the tablet and chewable capsule are solid forms, and while an intravenous solution is a liquid form, it is intended for injection rather than oral use, so it isn’t the form referred to as a liquid preparation for oral dosing.