Explain the Drug Effects on Absorption of Nutrients?

Many drugs can impair, prevent or reduce absorption of nutrients due to:

1. Formation of insoluble complexes: many drugs can chelate with minerals and trace elements e.g., antibiotics ciprofloxacin and tetracycline form insoluble complexes with calcium, magnesium, zinc or iron, thus preventing or reducing the absorption of these vital nutrients.
2. Competition for binding sites: e.g., salicylate drugs such as aspirin compete with vitamin C.
3. Damage to the absorptive surface of the intestinal mucosa: drugs used in chemotherapy can cause villous atrophy, resulting in malabsorption.
4.  Lack of bile acids : the absorption of fat-soluble vitamins such as vitamin A,D, E and K, will be impaired by bile salt binding drugs such as cholestyramine.
5. Increased intestinal mobility : drugs, which cause diarrhoea or stimulate peristaltic activity may result in nutrient losses.