The fixed dose combination of dutasteride/tamsulosin (DU/TA) has been licensed for the treatment of moderate to severe symptoms of benign prostatic hyperplasia (BPH) and for reducing the risk of acute urinary retention and surgery in patients with moderate to severe symptoms of BPH.
There is only one randomised clinical trial available comparing the efficacy and safety of the combination therapy with separate formulations of dutasteride and tamsulosin against monotherapy with either agent. Results from the study’s primary endpoint (reduction in the risk of acute urinary retention or the need for surgery) show that DU+TA was significantly superior to TA monotherapy but not to DU monotherapy, in terms of efficacy.
Some guidelines and consensus documents on the treatment of BPH in patients with moderate to severe symptoms and a high risk for disease progression (such as in elderly population) consider the administration of an alpha-blocker, such as TA, together with a 5-alpha reductase inhibitor (5-ARI), such a DU.
With regards to safety, adverse events (AE) were more frequent during combination treatment than during either monotherapy, however, withdrawal rates due to AE were similar across the treatment groups. There was no difference in overall cardiovascular events among the three study arms, although the incidence of cardiac failure was higher in the combination and tamsulosin monotherapy groups, and the incidence of libido disorders (ejaculation disorders and erectile dysfunction) was greater within the groups treated with dutasteride (both in combination or as monotherapy).
Evidence for the advantages of the administration of the combination alpha-blocker+5-ARI is sparse. The only available study has failed to prove that the fixed dose combination is in any way superior to DU in monotherapy, and, in terms of cost, despite the fact that this combination therapy is cheaper than the administration of both agents separately, it still is more expensive than other possible combinations of alpha-blocker plus 5-ARI.