Letters SSRIs and tamoxifen

Why condemn fluoxetine?

BMJ 2010; 340 doi: http://dx.doi.org/10.1136/bmj.c1319 (Published 10 March 2010) Cite this as: BMJ 2010;340:c1319
  1. Michael L Jenkinson, consultant physician
  1. 1Queen Elizabeth The Queen Mother Hospital, Margate, CT9 4AN
  1. michael.jenkinson{at}ekht.nhs.uk

    In their editorial promoting the CYP2D6 inhibition hypothesis as the explanation for the important interaction between paroxetine and tamoxifen, Andersohn and Willich use the hypothesis alone to justify the statement that, “for safety reasons, coprescription of fluoxetine and tamoxifen in women with breast cancer should be avoided until additional evidence becomes available.”1 But in one study, fluoxetine of all the antidepressants studied, had the lowest, if not statistically significant, all cause mortality during tamoxifen treatment.2 And another study found that fluoxetine also had one of the lowest (not statistically significant) recurrence rates in oestrogen receptor positive breast cancer of all common CYP2D6 inhibiting drugs.3

    Drug interactions are complex, and moving beyond the evidence with such a recommendation could cause unnecessary concern. Apart from paroxetine, the present evidence base raises no concern of increased risk of breast cancer occurrence or mortality.


    Cite this as: BMJ 2010;340:c1319


    • Competing interests: None declared.