Population-based data show that bariatric surgery strongly increases the chance for remission of T2DM. Gastric bypass and sleeve gastrectomy have a greater effect than gastric banding. Although the risks and possible adverse effects of surgery should be weighed against its benefits, bariatric surgery and, in particular, gastric bypass or sleeve gastrectomy may be considered as new treatment options for T2DM.

The purpose of this review is to evaluate the influence of bariatric surgery on the use and pharmacokinetics of some frequently used drugs. A PubMed literature search was conducted. Literature was included on influence of bariatric surgery on pharmacoepidemiology and pharmacokinetics. Drug classes to be searched for were antidepressants, antidiabetics, statins, antihypertensive agents, corticosteroids, oral contraceptives, and thyroid drugs. A reduction in the use of medication by patients after bariatric surgery has been reported for various drug classes. Very few studies have been published on the influence of bariatric surgery on the pharmacokinetics of drugs. After bariatric surgery, theoretically, reduced drug absorption may occur. Correct dosing and choosing the right dosage form for drugs used by patients after bariatric surgery are necessary for optimal pharmacotherapy. Therefore, more clinical studies are needed on the influence of bariatric surgery on the pharmacokinetics of major drugs.

No abstract

For some major drug classes 12 months after bariatric surgery, the use of drugs decreases in terms of mean number per patient. A reduction in dose intensity was observed for oral antidiabetics, beta-blocking agents, and lipid-modifying drugs. Dispensing data from pharmacies may provide detailed information on the use of medications by patients after bariatric surgery.

Objectives: To study the relation between serum and peritoneal levels of amphotericin B and flucytosine during intravenous treatment in patients with abdominal sepsis due to a perforated gut.Patients and methods: Included were consecutive patients with abdominal sepsis due to a perforated gut, who were treated intravenously with amphotericin B and/or flucytosine after surgery if an abdominal drain was present. Amphotericin B and flucytosine were measured from simultaneously collected serum and abdominal fluid samples.Results: Twenty-one consecutive patients were included. Five repeated samples were taken from three patients. The time interval between the start of the medication and the first sampling was median 4.0 days (range 2-7 days). The correlation coefficient (r 2 ) between serum and peritoneal levels of amphotericin B was 0.79. In nine patients (43%) with a maximum serum level of 0.28 mg/L, amphotericin B in the peritoneal fluid was undetectable. The lowest serum level that was present with a detectable peritoneal level was 0.16 mg/L. A short duration of treatment (2 days) was associated with low serum and undetectable peritoneal levels. In seven patients, flucytosine levels were measured. Peritoneal flucytosine levels did not differ significantly from serum levels. Serum and peritoneal flucytosine levels correlated well with r 2 5 0.88. Peritoneal amphotericin B level was inversely correlated with C-reactive protein level on the same day (r 2 5 0.30).Conclusions: It is shown, during continuous infusion, that peritoneal levels of amphotericin B are lower than serum levels. The amphotericin B serum levels should exceed 0.5 mg/L to obtain peritoneal levels above MIC values. Flucytosine levels in the abdominal fluid are comparable to serum levels and within MIC ranges.

Objective Roux-en-Y gastric bypass (RYGB) surgery induces major changes in the gastrointestinal tract that may alter the pharmacokinetics of orally administered drugs. Results from pharmacokinetic studies are sparse. This study aimed to investigate the effect of RYGB on the bioavailability of metoprolol from immediate release (IR) and controlled release (CR) tablets in female patient volunteers before and after surgery. Methods An explorative, two-phase, single oral dose pharmacokinetic study of metoprolol in female patients undergoing RYGB was carried out. The dose was administered twice in each patient, 1 month before and 6 months after surgery. After intake of either 100 mg of metoprolol IR or CR tablet serum concentration-time profiles of metoprolol were determined. The endpoint was the ratio of AUC after /AUC before of metoprolol. results Twelve patients were included in the study (metoprolol IR: 7; metoprolol CR: 5). After intake of a metoprolol IR tablet major intraindividual and interindividual differences for area under the serum concentration versus time curve (AUC) of metoprolol before and after surgery were observed (range ratio AUC 0-10 hours after /AUC 0-10 hours before : 0.74-1.98). For metoprolol CR tablets a significant reduction in bioavailability of metoprolol was observed after surgery (range ratio AUC 0-24 hours after /AUC 0-24 hours before : 0.43-0.77). Conclusion RYGB may influence the bioavailability of metoprolol from an IR tablet. The magnitude of changes in bioavailability after RYGB requires close monitoring of patients using metoprolol IR tablets and dose adjustment if deemed necessary. RYGB clearly reduces the bioavailability of metoprolol from a CR tablet. After RYGB clinicians may consider to increase the dose according to clinical response.

Informing patients and their general practitioners by letter, in addition to care-as-usual, is not an effective intervention to reduce the use of NSAIDs after bariatric surgery (trial number NTR3665).

Rectal absorption of morphine HCl from aqueous vehicles at different pHs in man has been compared with an orally administered solution. Plasma concentrations of morphine were measured by electrochemical HPLC analysis after a single dose of 10 mg morphine HCl, in a cross-over study in 7 volunteers. Rectal absorption of morphine was dependent on pH, which could be explained as being due to pH partitioning. The absorption rate and bioavailability could be greatly improved, as compared to orally administered morphine, by adjusting the pH. It was concluded that a rectal solution adjusted to pH 7 to 8 provided an entirely adequate dosage form.