Manic symptoms probably associated with short-term low-dose quetiapine use

Nowadays, there is a widespread use of atypical (second-generation) antipsychotics as an adjunct pharmacotherapy in psychiatry clinics, especially at lower doses in several diagnoses. Here, 2 cases are reported where patients with diagnosed schizophrenia displayed manic symptoms on quetiapine 100 mg/d. The cases presented here had no history of mood disorders. It is discussed that the mania/hypomania may be associated with quetiapine treatment and defined as an adverse effect. Manic symptoms may be a ‘probable adverse effect’ according to the Naranjo adverse drug reactions probability scale, with a score of 6 points in both our cases. Several studies have suggested that quetiapine-induced mania/hypomania may be associated with frontal dopamine release via serotonin 5HT2A receptor blockade. Hence, clinicians should monitor the mood alterations of patients carefully during the atypical antipsychotic treatment. This is also the conclusion of our study as the patients may be slow metabolisers of CYP450-3A4, as suggested by their previous side effects on different antipsychotics.