Polycarbophil

Polycarbophil is a hydrophilic, high molecular weight polymer used as a bulk-forming agent in medicine. It is a crosslinked polyacrylic acid polymer that exists commercially as the calcium salt, calcium polycarbophil, in many over-the-counter products. The polymer is not absorbed from the gastrointestinal tract and acts locally in the gut.

Mechanism of action is based on water absorption and gel formation. When hydrated, polycarbophil swells to form a viscous gel that increases stool bulk and moisture retention. This bulk effect helps normalize stool consistency and can ease passage. In addition to its laxative action, polycarbophil can adsorb water, bile acids, fatty acids, and certain toxins, contributing to stool stabilization and adsorptive benefits in the intestine.

Medical uses include treatment and prevention of constipation through bulk formation, and management of diarrhea by absorbing excess water and forming a gel that helps firm stools. It is also used as an intestinal adsorbent in certain OTC products designed to modify stool characteristics.

Administration and dosing are oral and should be accompanied by a full glass of water or other fluids. Dosing and product-specific instructions vary; users should follow package directions. To minimize potential interactions, polycarbophil should be spaced apart from other oral medications by about two hours.

Safety and tolerability are generally favorable. Common adverse effects include bloating, gas, and abdominal fullness. Rarely, it can cause constipation or, in susceptible individuals, an intestinal obstruction if insufficient fluids are consumed. It may bind certain drugs in the gut, so timing with other medications should be considered.