Hyperbolic dose reduction of escitalopram mitigates withdrawal syndrome: A case report

Antidepressants are widely used for the management of many psychiatric conditions; however, they are associated with side-effects including nausea and sexual dysfunction, which can lead to patient discontinuation, usually requiring gradual dose tapering. While conventional tapering is acceptable for some patients, a significant number experience a withdrawal syndrome not uncommonly resulting in continuation of antidepressant treatment. Consequently, patients remain unnecessarily on antidepressants for extended periods, often years. An alternative to conventional dose tapering is hyperbolic dose reduction based on serotonin transporter occupancy, which shows promising efficacy with several antidepressants in observational studies; however, no data is available for escitalopram, a widely prescribed antidepressant. While this method is an interesting proposal for antidepressant withdrawal, there are no randomised control studies to verify its clinical adequacy and capacity to prevent withdrawal. This case study reports on escitalopram discontinuation in a 25-year-old male receiving treatment for generalised anxiety and major depressive disorder, with a history of withdrawal syndrome associated with escitalopram, mirtazapine, and fluoxetine resulting in “brain zap” sensations, lethargy, and hypersomnia. Given the patients history with escitalopram and other antidepressants, they were at risk of experiencing a withdrawal syndrome again. As such, a hyperbolic dose reduction schedule was used as an attempt to reduce the severity or incidence of a withdrawal syndrome. The reduction schedule reduced the dose of escitalopram based on serotonin transporter occupancy, as calculated using the Michaelis-Menten equation in previous studies. The patient was taking 10mg and reduced the dose weekly to 5mg, 3mg, 1.5mg, 1mg, 0.5mg, and 0.25mg before cessation, delivering an approximate 10% reduction in serotonin transporter occupancy per step. The withdrawal severity was scored minimal to mild and was self-reported to be significantly better than previous antidepressant cessations. Depression and anxiety symptoms remained low throughout the taper and after cessation. For the first time in five years the patient had been antidepressant free with no significant withdrawal syndrome and remained so at three months post escitalopram discontinuation. Current data supports the need for further research into hyperbolic dose reduction of antidepressants compared to other dose reduction strategies.