Nursing Central: phenytoin

phenytoin

Pharmacokinetics

Absorption: Absorbed slowly from the GI tract. Bioavailability differs among products; the Dilantin and Phenytek preparations are considered to be "extended" products. Other products are considered to be prompt release.

Distribution: Distributes into CSF and other body tissues and fluids. Enters breast milk; crosses the placenta, achieving similar maternal/fetal levels. Preferentially distributes into fatty tissue.

Protein Binding: Adults 90–95%; ↓ protein binding in neonates (up to 20% free fraction available), infants (up to 15% free), and patients with hyperbilirubinemia, hypoalbuminemia, severe renal dysfunction or uremia.

Metabolism and Excretion: Mostly metabolized by the liver; minimal amounts excreted in the urine.

Half-life: 22 hr (range 7–42 hr).

TIME/ACTION PROFILE (anticonvulsant effect)

ROUTE	ONSET	PEAK	DURATION
PO	2–24 hr (1 wk)*	1.5–3 hr	6–12 hr
PO-ER	2–24 hr (1 wk)	4–12 hr	12–36 hr
IV	0.5–1 hr (1 wk)	rapid	12–24 hr

*( ) = time required for onset of action without a loading dose

phenytoin has been found in Davis's Drug Guide

If you are a registered user, please login below.

If not, learn more about gaining full access.

Login: User Name:

Password:

Forgot your password?
Forgot your username?
Remember Me

Try and Buy

Nursing Central puts five fully integrated references at your fingertips on mobile devices and the web. See how Nursing Central works by clicking the sample entries below or purchase a subscription for the web and your mobile device.

View these free topics online now.