Absorption of levodopa after rectal administration.

Absorption of levodopa was studied after administration by mouth and rectum. Given by mouth, levodopa benefited all 12 patients studied, and levodopa blood levels rose significantly (p less than 0.01). When it was given rectally, there was no rise in levodopa concentration in the blood and no clinical benefit. Rectally administered levodopa is therefore of no value in the management of postoperative parkinsonian patients who cannot take oral medication.