Tamoxifen SSRIs

A4 Barbiturates, carbamazepine, corticosteroids, efavirenz, phenytoin, rifampin, troglitazone Antiarrhythmics, antidepressants, azole antifungals, benzc iazepines, calcium channel blockers, cyclosporine, delavirdine, doxorubicin, efavirenz, erythromycin, estrogens, HIV protease inhibitors, nefazodone, paclitaxel, proton pump inhibitors, HMG-CoA reductase inhibitors, rifabutin, rifampin, sildenafil, SSRIs, tamoxifen, trazodone, vinca anticancer agents... 

Lash T et al (2010) Breast cancer recurrence risk related to concurrent use of SSRI antidepressants and tamoxifen. Acta Oncol 49(3) 305-312... 

Women taking tamoxifen should avoid taking drugs (eg, SSRIs) that inhibit CYP2D6. SSRIs such as venlafaxine are preferred treatment of hot flashes because they do not inhibit CYP2D6 paroxetine and fluoxetine should be avoided because they are potent inhibitors of CYP2D6. 

Paroxetine reduces the metabolism of tamoxifen to one of its active metabolites. The clinical relevance of this is unknown, although one small case-control study found that inhibitors of CYP2D6 such as the SSRIs did not increase the recurrence of breast cancer in tamoxifen users. 

Other SSRIs were also at no increased risk of recurrence. Patients with breast cancer with indications for an SSRI may therefore in the authors view be given citalopram, and possibly other SSRIs, without adversely affecting the outcome of adjuvant therapy with tamoxifen. 

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