Study to Evaluate the Pharmacokinetics of Vitamin D (Cholecalciferol) in Patients Undergoing Obesity Surgery in a Deficit Situation and After Standardization

Study to Evaluate the Pharmacokinetics of Vitamin D (Cholecalciferol) in Patients Undergoing Obesity Surgery in a Deficit Situation and After Standardization

Set the pattern of vitamin D supplementation in obese patients undergoing bariatric surgery in deficit of vitamin D.

Patients receive a single oral dose of vitamin D, during the 28 days will be done a kinetic curve. Then and over the next 3 months, levels are normalized. Once normalized, will be administered another single oral dose to a second pharmacokinetic evaluation.

The study is conducted in obese patients undergoing bariatric surgery (for bypass or sleeve gastrectomy) in deficit of vitamin D.

Will include a total of 44 patients, 22 from each type of surgery. Patients receive a single oral dose of vitamin D of 50,000 IU. During the 28 days after administration of vitamin D will be done a kinetic curve determining plasma levels of vitamin D on 15 occasions. Then and over the next 3 months, levels are normalized by providing a daily oral dose for each patient. Once levels are normalized, will be administered another single oral dose of 50,000 IU vitamin D and proceed to a second pharmacokinetic evaluation determining plasma levels 15 times.

Patient follow up is approximately 36 weeks. Patients go to the screening visit, baseline visit and visits on days 1, 2, 3, 14 and 28 days after each pharmacokinetic evaluation.

Inclusion Criteria:

• 18 or more years old
• with bariatric surgery in the last 18 months (+/- 6 months)
• BMI: 25-33 kg/m2
• vitamin D3 (OK)<20ng/mL.
• Clinically stable, in the opinion of the investigator, at the time of inclusion
• Signed consent form

Exclusion Criteria:

• pregnancy, lactation or intention during the study period.
• menopause
• GOP, GPT>2 UNL
• glomerular filtration rate <60ml/min
• previous renal lithiasis
• any digestive disease to suggest malabsorption, granulomatous diseases, diabetic gastroenteropathy and taking medication likely to interfere with the absorption of vitamin D and bone metabolism such as corticosteroids and anticonvulsants
• taking medication that interferes with calcium metabolism.
• cholecalciferol hypersensitivity.
• other bariatric surgery (different of by-pass or tubular gastrectomy)