Bariatric Surgery, Malabsorption of Medications and the Benefits of Compounding

Bariatric Surgery, Malabsorption of Medications and the Benefits of Compounding

i-pillBariatric surgery heralds the beginning of better health, but this fresh start also comes with challenges. Melinda gets sick when she forgets to thoroughly chew food, but that’s a small challenge and one she believes is a fair trade for losing weight. Sam had a bigger challenge. He was diabetic and after gastric bypass, he suffered through many months of poorly controlled glucose as the proper medication dose was tricky to balance. Malabsorption of medications—and the need to decrease meds for some chronic diseases—are significant challenges following bariatric surgery. The expertise of compounding pharmacists is essential to guide dosing decisions and to mix alternative forms of medications.

Obesity Rates Plus Benefits from Gastric Bypass Signal More Surgeries

The CDC estimates that 35 percent of adults and 20.5 percent of adolescents are obese. Children between the ages of 6 to 11 aren’t far behind, with nearly 18 percent in the same category. But the statistics don’t stop there. A shocking 8 percent of 2-to 5-year-olds are also obese.1 Bypass surgery promotes more weight loss than non-surgical approaches in adults. It’s increasingly considered as a treatment option for obese teens, especially in light of news from Cincinnati Children’s Hospital that teens undergoing weight loss surgery continued to lose weight and see improvement in lipid profiles for eight years.2

Bariatric surgery has a remarkable impact on type 2 diabetes. Diabetes-related deaths declined by 92 percent following gastric bypass, with blood glucose normalizing in 80 to 100 percent of patients.3 Health benefits from bariatric surgery aren’t limited to diabetes. In November 2015, NYU Langone Medical Center researchers reported that at least half of their obese patients who also suffered from psoriasis and psoriatic arthritis experienced significant symptom relief following weight-loss surgery.4 Predictions that the incidence of obesity will continue to rise—combined with new research showing benefits for chronic disease—means the number of surgeries performed will continue to increase.

Medication Malabsorption Following Bariatric Surgery

Bariatric surgery affects solubility, absorption and first-pass metabolism of medications, depending on the type of medication and the surgery performed. All types of bariatric procedures restrict food intake by reducing stomach size, which impacts medications that need the acidic environment. Capsules and large tablets also tend to get stuck in a small stomach pouch. Bariatric surgeries that are purely restrictive include sleeve gastrectomy, gastric banding and vertical banded gastroplasty. The most common bypass procedure—Roux-en-Y—also eliminates absorptive surface in the duodenum. It reduces the stomach to a 15 to 30 milliliter gastric pouch, then attaches the stomach to the proximal jejunum. Another procedure—biliopancreatic diversion with duodenal switch—removes about 80 percent of the stomach and reconnects it to the distal small intestine.

“Practitioners looking for guidance in tailoring pharmacotherapy to the RYGB patient will find little help in the primary literature at this time,” wrote researchers in the American Journal of Health-System Pharmacy in 2011.5 In 2014, it was still referred to as an under-researched area. Lacking pharmacokinetic studies, physicians must make a well-calculated estimate about medication dosages for patients following bariatric surgery. Of course, pharmacists are the experts so they are vital collaborators. Don’t hesitate to reach out to local physicians—especially primary care physicians responsible for long-term care—to build a relationship and enhance your business.

Key Guidelines for Patients Post-Bariatric Surgery

It’s valid to argue that every doctor prescribing for patients who have had bariatric surgery should consult a pharmacist. Evaluating how each medication might respond to changes in intestinal transport mechanisms, higher pH in the small intestine and compromised drug-metabolizing enzymes—to name just a few variables—is a job for pharmaceutical specialists. However, you can begin with a few key guidelines:

Chronic health conditions: High blood pressure, diabetes, dyslipidemia and gastric reflux often improve quickly and require numerous changes in dosage. Medications for reflux are generally discontinued, while blood pressure and blood glucose must be closely monitored and medication adjustments made accordingly. Half of patients taking lipid-lowering meds prior to surgery are able to reduce the dose afterwards, but they must be monitored for the long run because systemic exposure to medications such as atorvastatin may change two years after surgery.6

Psychiatric medications: About 20 to 50 percent of bariatric surgery patients have a history of mood disorders. Only 16 percent are able to reduce their medications following surgery and most continue antidepressant therapy. It’s critical to monitor these patients to avoid relapse due to reduced bioavailability.7

OTC medications to avoid: With an increased risk for developing an ulcer, patients are instructed to avoid aspirin, aspirin-containing products and NSAIDs following bariatric surgery. But there’s no way to anticipate who will comply with the guidelines versus who will reach for their favorite product to treat a nagging headache. They’re even less likely to worry about whether they purchase an immediate-release or time-release product. Pharmacists can step in to offer options, including topical NSAIDs to reduce systemic side effects.

Lipophilic drug differences: The decrease in adipose tissue affects the distribution of lipophilic drugs and shortens their half-life. Primary care physicians who adjust for the more obvious absorption issues may be less likely to consider this factor.

Oral contraceptive warnings: Oral contraceptives are not reliably absorbed after gastric bypass. Women should be advised to use other methods of birth control, such as an implant, a patch or a contraceptive injection.

Short list of meds with reduced absorption: While this list isn’t close to comprehensive, a review published in February 2013 noted reduced absorption of phenytoin, fluoxetine, sertraline, cyclosporine, tamoxifen, warfarin, thyroid hormone and anti-tuberculosis medication. Erythromycin took 85 percent longer to reach peak concentration and its peak concentration was half the amount prior to surgery.8

Solutions Offered by Compounding Pharmacists

The 113,000 bariatric surgeries currently performed each year represent a large number of patients who can benefit from solutions available through compounding pharmacists. Whether you reach out to physicians or patients, it’s up to you to make them aware that compounding topical applications or liquid and sublingual formulations offer solutions to absorption issues. Remember that your expertise is always invaluable, but it’s especially vital in light of sparse studies and lack of dosage recommendations. Compounding pharmacists are positioned to make an essential difference while building their business.

Pharmaceutica North America provides custom compounding kits, bulk APIs and highly absorptive delivery systems to support the compounding needs of bariatric surgery patients. Contact us today to talk about how our quality products can benefit your business.

Show 8 footnotes

  1. “FastStats: Obesity and Overweight,” September 2015, http://www.cdc.gov/nchs/fastats/obesity-overweight.htm
  2. “Gastric Bypass for Teens: Weight Loss and Lipid Improvements Sustained Eight Years After Surgery,” November 2015, https://www.sciencedaily.com/releases/2015/11/151110093920.htm
  3. “Bariatric Surgery for Type 2 Diabetes Reversal: The Risks,” May 2011, http://care.diabetesjournals.org/content/34/Supplement_2/S361.full
  4. “Psoriasis and Psoriatic Arthritis Symptoms Curbed by Bariatric Surgery,” November 2015, https://www.sciencedaily.com/releases/2015/11/151108084033.htm
  5. “Pharmacokinetic Considerations in Roux-en-Y Gastric Bypass Patients, 2011, http://www.medscape.com/viewarticle/754391
  6. “Long-Term Effects of Gastric Bypass and Duodenal Switch on Systemic Exposure of Atorvastatin,” June 2013, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3661042/
  7. “The Use of Drugs in Patients Who Have Undergone Bariatric Surgery,” May 2014, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4026560/
  8. “Vitamin, Mineral, and Drug Absorption Following Bariatric Surgery,” February 2013, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3571763/
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