Moclobemide and paroxetine

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Editor, – I would like to draw your readers' attention to the discrepancy between the product information for moclobemide and paroxetine.

The product information for moclobemide reads 'There are limited data ... to support the safety of changing from low to moderate doses of seroton inreuptake inhibitors (SRI) to moclobemide 300 mg/day by ceasing the SRI on one day and starting moclobemide on the next.'

The product information for paroxetine reads 'MAO inhibitors should not be introduced within 2 weeks of therapy with paroxetine.'

These appear to be in conflict.

Julian Fidge
Graduate medical student
University of Queensland
Herston, Qld

The Editor comments:
Both statements quoted in Julian Fidge's letter are correct and not in conflict. There are limited data to support the safety of changing from low to moderate doses of selective serotonin reuptake inhibitors (SSRIs) to moclobemide300 mg/day by ceasing the SSRI one day and starting moclobemide on the next. The product information for paroxetine, and for other SSRIs, refers only topotential interactions with (irreversible non-selective) monoamine oxidase inhibitors (MAOIs). There is no reference in the current Australian product information for any SSRI regarding interactions (if any) with reversible selective inhibitors of monoamine oxidase A in general, or moclobemide in particular.

Moclobemide is more restricted in actions and is a different monoamine oxidase inhibitor to the old MAOIs. The letter highlights the confusion which may arise when lumping medicines into classes. It may not be entirely clear which medicines are, or are not, members of a specific class. Furthermore, the effects of one drug in the class may not occur with the other members of that class.

For advice on changing antidepressant treatment, see the advice in the 'Psychotropic Drug Guidelines' Edition 3, 1995 of the Victorian Medical Postgraduate Foundation Therapeutics Committee. (This does not include advice on subsequently registered antidepressants.)