Nothing up his sleeve: Decompensation after bariatric surgery
Mr. G, age 64, has schizoaffective disorder and has been stable for years. Weeks after undergoing bariatric surgery, he rapidly develops depressive symptoms. What could be the cause?
The 5 oral formulations of medications that contain valproic acid include:
- syrup
- capsule
- sprinkle
- enteric-coated delayed-release and extended-release
A parenteral form via IV is available for patients who are unable to swallow.
Absorption vs delivery
Any gastric bypass surgery can have postoperative complications, one of which can include absorption deficiencies of vitamins and minerals. Sleeve gastrectomy has the least amount of absorption-related nutritional deficiencies.14 Additionally, this procedure preserves the stomach’s ability to produce gastric acid. Therefore, regardless of formulation, there should be no initial postsurgical need to change psychotropic medication formulations. However, because VPA is related to B-vitamin deficiency, supplementation can be considered.
Omeprazole is a PPI that increases pH in the stomach and is often prescribed to promote healing of gastric surgery. However, in Mr. G’s case, omeprazole created a non-acidic environment in his stomach, which prevented the divalproex sodium ER formulation from being dissolved and the medication from being delivered. Mr. G’s absorption ability was preserved, which was confirmed by his rapid recovery and increased serum VPA levels once he was switched to the IR formulation. There is no literature supporting a recommended length of time a patient can receive omeprazole therapy for sleeve gastrectomy; this is at the surgeon’s discretion. Mr. G’s prescription for omeprazole was for 3 months.
Proper valproate dosing
In Mr. G’s case, it could be hypothesized that the VPA dosing was incorrect. For mood disorders, oral VPA dosing is 25 mg/kg/d. Mr. G lost 40 pounds, which would translate to a 450-mg reduction in dose. Despite maintaining his original dose, his serum VPA levels decreased by almost 50% and could not be attributed to trough measurement. In this case, Mr. G was prescribed a higher dose than needed given his weight loss.
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