The solubility of a drug, surface area for absorption, and blood flow to the gastrointestinal tract influence oral absorption and bioavailability. Drug solubility and surface area for absorption are affected by gastric bypass procedures. Drugs in aqueous solution are more rapidly absorbed than those in oily solutions, suspensions, or solid form. When medications are given as tablets, the times to disintegration and dissolution of the tablet affect absorption. In early drug trials, these factors are accounted and adjusted for to ensure adequate absorption in patients with unaltered gastrointestinal tracts. However, reductions in the amount of functioning gastrointestinal tract after gastric bypass surgery lead to decreased time to drug absorption and reduced drug bioavailability.
Considerations for Nutrient Replacement
Nutrient deficiencies in patients who have had restrictive procedures have been reported.the exact prevalence is unknown. Because restrictive procedures retain the use of the entire gastrointestinal tract, nutrient deficiencies are less common than in patients who have had gastric bypass procedures. After gastric bypass procedures, patients are prone to deficiencies of the fat-soluble vitamins (A, D, E, and K) and calcium.In addition, these patients have an increased risk of developing anemia secondary to potentially inadequate amounts of iron, vitamin B12, and folate. Because of these deficits, all patients should receive a daily multivitamin and calcium supplementation indefinitely.In patients with anemia, additional supplementation with iron, vitamin B12, and folate may be necessary.
Get Answers For Free
Most questions answered within 1 hours.