How can changes in absorption resulting from CKD alter the pharmacokinetic behavior of drugs?
• Alkaline saliva. As CKD progresses, saliva becomes more alkaline. This compromises absorption of drugs that need an acid milieu (e.g., iron supplements) and contributes to a higher gastric pH.
• Nausea and vomiting may reduce drug ingestion and absorption.
• Volume overload states: Edema of the gastrointestinal tract limits absorption.
• Drug interactions: Many drugs used in the management of CKD limit drug absorption by forming nonabsorbable complexes (e.g., iron, phosphate-binding agents).
• Gastrointestinal neuropathy: Uremia may delay gastric emptying time, particularly in patients with diabetes.
