Congestive heart failure and lower drug absorption

 

Congestive heart failure and lower drug absorption

·        Inability of the heart to pump adequate blood in the circulation leads to congestive heart failure

·        In this condition, blood reaching systemic circulation is inadequate. As a compensatory mechanism there is vasodilation in vital organs like brain, kidneys and vasoconstriction in less vital organs like skin, gut, muscles. Vasoconstriction in blood vessels supplying the gut and allied organs is known as splanchnic vasoconstriction.

·        Venous return also decreases because the pressure build up in the failing heart is transmitted backwards resulting in increase in central venous pressure

·        Increase in venous pressure causes oozing of plasma into the interstitial space causing oedema including the intestinal mucosal oedema.

·        Absorption occurs when drug molecules in the gut lumen move across the gut mucosa into the capillaries and reaches systemic circulation via the portal vein.

·        As venous return is decreased in congestive heart failure, the absorption of drugs from the gut is also decreased.