Laxatives With Antraquinones Associated With Melanosis Coli

The finding of pigmented mucosa-melanosis coli-on colonoscopy is associated with which of the following laxatives?

A. Senna
B. Docusate sodium (Colace)
C. Polyethylene glycol (Miralax)
D. Milk of magnesia

Correct answer: A

Laxatives that contain antraquinones (eg, senna) can induce a dark pigmentation in the colonic mucosa. The cecum and rectum are the most commonly affected sites. Despite its appearance on colonoscopy, melanosis coli is a benign finding. The other laxatives do not cause this condition.