Comments on: “Lithium Toxicity Following Roux-en-Y Gastric Bypass” including Perioperative Lithium Dosing Protocol

Abstract

Dear Editor:

We read with interest the recent publication “Lithium Toxicity Following Roux-en-Y Gastric Bypass” by Walsh and Volling.¹ The authors present a case of a 53-year-old female, post-bariatric surgery patient who developed lithium toxicity, despite the use of a lithium monitoring and dose modification protocol.

We are familiar with this patient, as we were the psychiatrists who managed her issues perioperatively. The following protocol referred to by the authors is our Toronto Western Hospital clinic protocol, which we believe is important to share for the benefit of our colleagues who work with bariatric surgery patients who are on psychotropic medications.

It was also mentioned in the article that the patient was advised to crush her immediate release lithium for 4–6 weeks after surgery. We actually do not recommend the crushing of immediate release lithium, since lithium—when compared to 21 common psychiatric immediate release medications—dissolves significantly more rapidly in the post-RYGB model compared to the preoperative control environment.²

Toronto Western Hospital Bariatric Surgery Program: Perioperative Lithium Dosing Protocol

Lithium levels can be altered perioperatively when patients undergo bariatric surgery due to significant changes in food intake, fluid status, and postoperative changes to medication dissolution. During the presurgery phase, all patients will take Optifast (meal replacement) or a comparable nutrition regimen as part of the surgery preparation. Optifast will alter fluid intake and salt intake, both of which can influence lithium levels.

Post-bariatric surgery patients may experience changes in lithium levels due to reduced fluid intake, electrolyte shifts, and increased dissolution of lithium resulting in potentially increased lithium absorption.

In some cases of patients on lithium, a clinical decision can be made to switch the lithium to an alternative medication such as another mood stabilizer or an antipsychotic medication. In other cases, it might be a more appropriate clinical decision to keep the patient on lithium.

If it is decided to keep a patient on lithium, then close monitoring and follow-up by a psychiatrist or family physician pre- and post-bariatric surgery is recommended. We recommend adherence to the following protocol to minimize lithium toxicity and to monitor for lack of efficacy (Table 1).

Table 1.

Bariatric Surgery Lithium Monitoring and Dose Modification Recommendations

Bariatric Surgery Perioperative Phase	Recommendations
Pre-Surgery: While Taking Optifast^*	• Weekly lithium levels • Educate patient to drink 2.5-3 L per day • Consider lithium dose decrease if lithium levels approach 1.2 mmol/L or increase by >25% from baseline • Hold and reassess dose if signs of lithium toxicity • Monitor depressive or manic symptoms (consider using standardized scales^**)
Post-Surgery 0–6 Weeks Post-Surgery	• Weekly lithium levels • Ask about changes fluid intake (will increase gradually) and sodium consumption (will vary with diet changes) post-surgery^*** • Ask about food intolerance and vomiting as it can impact fluid intake • Consider lithium dose decrease if lithium levels approach 1.2 mmol/L or increase by >25% from baseline • Hold and reassess dose if signs of lithium toxicity • Monitor depressive or manic symptoms (consider standardized scales)
Post-Surgery >6 Weeks Post-Surgery	• Monitor lithium levels 2weeks until 6 months post-surgery and then proceed to monthly lithium levels until 1 year post-surgery • Ask about food intolerance and vomiting as it can impact fluid intake • After 1 year post-surgery, resume routine lithium monitoring • Diet should be more stable during this phase post-surgery but monitor for any major diet changes influencing sodium intake

Note: Lithium levels should be trough levels.

Duration of Optifast or equivalent meal replacement is based upon pre-surgery weight.

Standardized rating scales include the 17-item or 7-item Hamilton Depression Rating Scale or Patient Health Questionnaire-9 for depression and the Young Mania Rating Scale for mania.

***

Gradual increase from ∼1-1.5 L/day to 2-2.5 L/day first few months post-surgery.

Raed Hawa, MD, FRCPC, DABPN

Deputy Psychiatrist in Chief (THW and TRI)

Associate Professor, Department of Psychiatry

Faculty of Medicine, University of Toronto

Sanjeev Sockalingam, MD, FRCPC

Deputy Psychiatrist in Chief (TGH and PMH)

Associate Professor, Department of Psychiatry

Faculty of Medicine, University of Toronto

Footnotes

Author Disclosure Statement

No competing financial interests exist.

References

Walsh

, Volling

. Lithium toxicity following Roux-en-Y gastric bypass. Bariatr Surg Practice Patient Care, 2014; 9:77–80.

Seaman

, Bowers

, Dixon

, Schindler

. Dissolution of common psychiatric medications in a Roux-en-Y gastric bypass model. Psychosomatics, 2005; 46:250–253.