NIKP-Dutasteride Adverse Reactions

Dutasteride as Monotherapy: Approximately 19% of the 2,167 patients who received Dutasteride in the 2 year Phase III placebo-controlled trials developed adverse reactions during the first year of treatment. The majority of events were mild to moderate and occurred in the reproductive system. No change to the adverse event profile was apparent over a further 2 years in open-label extension studies.
The following table shows adverse reactions from controlled clinical trials and post-marketing experience. The listed adverse events from clinical trials are investigator-judged drug-related events (with incidence more than or equal to 1%) reported with a higher incidence in patients treated with Dutasteride compared with placebo during the first year of treatment. Adverse events from post-marketing experience were identified from spontaneous post-marketing reports; therefore the true incidence is not known: Very common (≥1/10); Common (≥1/100 to <1/10); Uncommon (≥1/1,000 to <1/100); Rare (≥1/10,000 to <1/1,000); Very rare (<1/10,000); not known (cannot be estimated from the available data). (See Table 2.)

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Dutasteride in Combination with the Alpha-blocker Tamsulosin: Data from the 4 year CombAT Study, comparing Dutasteride 0.5 mg (n=1,623) and Tamsulosin 0.4 mg (n=1,611) once daily alone and in combination (n=1,610) have shown that the incidence of any investigator-judged drug-related adverse event during the first, second, third and fourth years of treatment respectively was 22%, 6%, 4% and 2% for Dutasteride/Tamsulosin combination therapy, 15%, 6%, 3% and 2% for Dutasteride monotherapy and 13%, 5%, 2% and 2% for Tamsulosin monotherapy. The higher incidence of adverse events in the combination therapy group in the first year of treatment was due to a higher incidence of reproductive disorders, specifically ejaculation disorders, observed in this group.
The following investigator-judged drug-related adverse events have been reported with an incidence of greater than or equal to 1% during the first year of treatment in the CombAT Study; the incidence of these events during the four years of treatment is shown in the table as follows: See Table 3.

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Other Data: The REDUCE study revealed a higher incidence of Gleason 8-10 prostate cancers in Dutasteride treated men compared to placebo (see Precautions and Pharmacology: Pharmacodynamics under Actions). Whether the effect of Dutasteride to reduce prostate volume, or study related factors, impacted the results of this study has not been established.
The following has been reported in clinical trials and post-marketing use: male breast cancer (see Precautions).