Venlafaxine deprescribing and thyroid function.

Study Objective: This report highlights the effects of discontinuing venlafaxine on thyroid function in an older adult with previously well-managed Hashimoto thyroiditis and sleep apnea.

Design: Concurrent intervention.

Case Study: Setting Community-based psychiatry practice Patient - 66 year old female Intervention Over 8 months, a 66-year-old patient slowly reduced the venlafaxine dose. She was treated simultaneously for sleep apnea. Measurements Clinical data including venlafaxine and levothyroxine dosing, thyroid hormone laboratory values, subjective complaints, and objective electrocardiographic (ECG) findings were aggregated and analyzed.

Main Results: As venlafaxine dose was decreased over time, the patient complained of bounding heart palpitations shown to be premature ventricular contractions, and wide and narrow complex ventricular tachycardia on ECG. Thyroid-stimulating hormone decreased from a baseline value of 0.791 uIU/mL to a nadir of 0.18 uIU/mL during venlafaxine dosage reduction from 225 mg/day to 155 mg/day. Cardiac symptoms subsided following levothyroxine dosage reduction.

Conclusions: There was a direct relationship between antidepressant dosage reduction and levothyroxine dosage requirements. Cautious monitoring is recommended during venlafaxine deprescribing in patients with pre-existing thyroid disease.