Analysis of the Influence of Gastric By-Pass on the Pharmacokinetics of Common Drugs

The aim of this study is to investigate the pharmacokinetics of some of the most frequently prescribed oral drugs in hospital and outpatient medicine, in patients undergoing GBP surgery for obesity associated with metabolic syndrome. Paradoxically, despite their frequency of use, very few data, contradictory data or no data at all characterize the molecules we wish to study.

The number of patients undergoing GBP surgery is growing rapidly, as their life expectancy reaches that of the general population once their weight has normalized. However, while weight loss induced by surgery can improve, and more rarely cure, the comorbidities associated with metabolic syndrome, the majority of patients will need to continue or modify their treatments.

It is therefore essential to know the pharmacokinetics of the antihypertensive, lipid-lowering and hypoglycemic drugs they will be taking throughout their lives, in order to adapt their dosage if necessary, or even to change therapeutic class if their absorption is insufficient after GBP.

Moreover, as some studies have shown, the pharmacokinetics of many molecules are likely to vary over time in these patients (19), probably as a result of weight loss itself, but also possibly due to adaptive phenomena in the digestive tract. Studying the pharmacokinetics of the molecules used in the usual treatment of metabolic syndrome in most obese patients should make it possible to: target the preferred sites of absorption in the digestive tract of the molecules studied, study the variations in absorption linked to GBP but also the pharmacokinetic changes linked to weight loss as a function of time. In fact, metabolic capacity may be both decreased and increased in obese patients compared to healthy subjects (20,21), so that drug clearance may both increase and decrease after weight normalization. It is therefore difficult to predict the pharmacokinetics of drugs immediately or long after GYP. The results obtained should make it possible to adapt treatment in these patients, both in terms of changing the dosage administered and in the choice of molecules.

• Determine changes in apparent clearance at 6 months after gastric bypass surgery compared with the pre-operative phase [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Explain changes in apparent clearance as a function of weight loss [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Explain changes in apparent clearance as a function of changes in the fat/lean mass ratio [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Determine changes in apparent volumes of distribution between the pre-operative phase and 1 and 6 months after surgery [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Explain changes in apparent volumes of distribution as a function of body weight loss [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Explain changes in apparent volumes of distribution as changes in body fat [Срок оценки: pre-operative phase and 1 and 6 months after surgery]
• Based on the results obtained, recommend any necessary changes in dosage or therapeutic class for these molecules [Срок оценки: pre-operative phase and 1 and 6 months after surgery]