Can quetiapine extended release (ER) induce labial edema in a female patient with treatment-resistant major depressive episode?

Abstract

Major depressive episode (MDE) is a clinical condition affecting about 350 million people worldwide, and leading a high morbidity and mortality. There are a large proportion of patients who still do not always respond to currently available and conventional pharmacological treatments (antidepressant medication). Rates of treatment-resistant depression (TRD) range from 2–3 to 30 %, vary according to the threshold of unsuccessful trials: it remains, however, a significant clinical challenge [1]. Quetiapine extended release (ER) is classified as an atypical antipsychotic that is commonly prescribed for a broad range of psychiatric conditions, also in off label use (such as sleep disturbances in dementia, anxiety and personality disorders). It has been approved and proven to be effective in the treatment of schizophrenia, bipolar disorder (acute phases and long-term treatment) and, recently, as an adjunctive agent in patients with partial or no response to a conventional treatment [2]. It is mainly metabolized in the liver via cytochrome P450 isoenzyme CYP3A4 and it is characterized by the weakest affinity for dopamine D2 receptors of all the antipsychotics: this drug certainly binds D2 receptors, but rapidly dissociates from them. It exhibits a strong affinity for antagonism at histamine H1-receptors, similar to that of diphenhydramine, amitriptyline, mirtazapine, and has a moderate affinity for serotonin type 2A (5-HT2A) receptors. Other neurotransmitter systems are involved such as serotoninergic (5-HT2C, 5-HT6, 5-HT7), adrenergic (a1, a2), muscarinic (M1, M3) receptors, and a partial agonist to serotonin 5HT1A receptors. Case reports reporting peripheral edema induced by quetiapine are described in literature [3] but no case report exists reporting labial edema.