PHENYTOIN; EPTOIN

What this test checks

Measures phenytoin, a long-used seizure medicine, in your blood. Levels must stay in a narrow safe range.

Why do people get this test?

Routine monitoring while on phenytoin to ensure the dose is right.

When you should consider this test

• Currently on phenytoin (Eptoin)
• New side effects
• Dose adjustment needed

How to prepare

Take the sample at the time your doctor specifies (usually before your morning dose).