Table 1.

Drug delivery considerations with gastric surgical procedures

Physiological impact	Gastric surgical procedure	Drug delivery considerations
Dumping syndrome	▪  Parietal cell vagotomy is associated with less frequency of the dumping syndrome in comparison to truncal vagotomy ▪  Resection of the pylorus can accelerate gastric emptying ▪  Dumping syndrome is a common complication of bariatric surgery (esp. RYGB and BPD)	▪  May affect drug formulations that are dependent on gastrointestinal transit time to trigger drug release, leading to reduce efficacy
Increased gastric pH	▪  Gastrectomy can lead to the production of less hydrochloric acid ▪  Surgical procedures that interfere with pyloric function may lead to reflux of alkaline duodenal fluid into the stomach	▪  May reduce the absorption of drugs that require an acidic environment for dissolution ▪  May trigger premature release of drugs from formulations that have pH-responsive coatings or matrices
Post-surgery diarrhea	▪  Truncal vagotomy may cause diarrhea (episodic or persistent) ▪  Bariatric surgery may cause diarrhea (e.g., diet high in fat can lead to diarrhea following BPD procedure)	▪  May reduce the time available for drug absorption ▪  May cause inefficient release of drugs from formulations that are dependent on gastrointestinal transit time ▪  Can affect other physiological factors in the gastrointestinal tract (e.g., intestinal volume, pH, mucosal integrity, and resident microbiome)
Chronic gastroparesis	▪  Gastroparesis can occur post-vagotomy when the vagus nerve is damaged	▪  May affect the time available for disintegration, dissolution, and/or drug absorption ▪  Premature drug release may occur in the stomach due to the prolonged gastric transit time
Anastomoses	▪  Gastric surgery with anastomoses is common with bariatric surgery (e.g., RYGB and BPD) ▪  Anastomoses may also be needed following other gastrectomy procedures to ensure alimentary continuity	▪  Until the anastomoses are healed, drugs should be delivered in their immediate-release formulation and ideally in a liquid dosage form or crushed ▪  After anastomoses are healed, whole pills can be administered (< 11 mm in size) ▪  Consider other routes of drug administration