Other anionic drugs undergoing enterohepatic circulation in intestinal lumen

The term 'Other anionic drugs undergoing enterohepatic circulation in intestinal lumen' refers to a broad class of pharmacological agents that are excreted into the bile and subsequently reabsorbed from the small intestine, a cycle known as enterohepatic circulation (EHC). This process significantly extends the pharmacological half-life of drugs such as mycophenolic acid, warfarin, and certain antibiotics (Roberts et al., 2002). These drugs are typically organic acids that exist as anions in the intestinal environment. While not a biological receptor or enzyme, this category is clinically significant as a site of drug-drug interactions involving bile acid sequestrants like colestyramine. These sequestrants act as anion exchange resins that bind to the anionic drugs in the intestinal lumen, forming non-absorbable complexes that are excreted in the feces (DrugBank, 2024). This interaction effectively interrupts the EHC, leading to a rapid decline in the plasma concentration of the affected drug, which can be utilized to treat drug toxicity or may inadvertently lead to therapeutic failure (StatPearls, 2023). Consequently, monitoring drug levels and timing of administration are essential when these agents are co-administered.

Other names

Anionic drug substratesEnterohepatically circulated drugsAcidic drugs in the intestinal lumenAnionic drugs

Physical sequestration and ionic binding of anionic drug molecules by anion exchange resins within the intestinal lumen, preventing their reabsorption into the portal venous system.