Olanzapine/fluoxetine combination for treatment-resistant depression: efficacy and clinical utility

Abstract

Antidepressant monotherapy is a first-line treatment for depression; however, not all sufferers will adequately respond to treatment. When treating a patient with treatment-resistant depression, the clinician needs to consider all factors which may contribute to an inadequate response to an antidepressant. These include accuracy of diagnosis and medication adherence, as well as the patient’s personality, lifestyle, life events and social circumstances. If it is determined that treatment resistance is due to failure of efficacy of antidepressant monotherapy, then an augmentation strategy using an atypical antipsychotic may be considered. Treatment using olanzapine/fluoxetine combination (OFC) is one of many options. Four randomized, acute-phase trials have suggested OFC is useful for reducing Montgomery–Åsberg Depression Rating Scale scores after inadequate response to antidepressant monotherapy. OFC has been useful at doses of olanzapine/fluoxetine 6/25, 6/50, 12/25 and 12/50 mg/day, with 1/5 mg/day suggested to be an ineffective dose. Treatment with OFC has been associated with some side effects, including weight gain and the metabolic syndrome, somnolence, dry mouth, increased appetite and headache. Treatment decisions therefore need to be made to balance the risks and benefits.

Keywords::

• antidepressant
• atypical antipsychotic
• olanzapine/fluoxetine combination
• treatment-resistant depression

Financial & competing interests disclosure

Seetal Dodd has received grant/research support from: Stanley Medical Research Foundation, NHMRC, Beyond Blue, Geelong Medical Research Foundation, Bristol Myers Squibb, Eli Lilly, GlaxoSmithKline, Organon, Novartis, Mayne Pharma, Servier. Seetal Dodd has also acted as a speaker for Eli Lilly.

Michael Berk has received grant/research support from: Stanley Medical Research Foundation, MBF, NHMRC, Beyond Blue, Geelong Medical Research Foundation, Bristol Myers Squibb, Eli Lilly, GlaxoSmithKline, Organon, Novartis, Mayne Pharma, Servier. Michael Berk has also acted as a consultant or speaker for: Astra Zeneca, Bristol Myers Squibb, Eli Lilly, GlaxoSmithKline, Janssen Cilag, Lundbeck, Pfizer, Sanofi Synthelabo, Servier, Solvay, Wyeth.

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.