Duodart Adverse Reactions

The data presented here relate to the co-administration of dutasteride and tamsulosin from the 4 year analysis of the CombAT (Combination of Avodart and Tamsulosin) study, a comparison of dutasteride 0.5mg and tamsulosin 0.4mg once daily for four years as co-administration or as monotherapy. Bioequivalence of Duodart with co-administered dutasteride and tamsulosin has been demonstrated (see Pharmacology: Pharmacokinetics under Actions). Information on the adverse event profiles of the individual components (dutasteride and tamsulosin) is also provided. Note that not all the adverse events reported with the individual components have been reported with Duodart and these are included for information for the prescriber.
Data from the 4-year CombAT study have shown that the incidence of any investigator-judged drug-related adverse event during the first, second, third and forth years of treatment respectively was 22%,6%, 4% and 2% for dutasteride + tamsulosin co-administration 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 co-administration 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 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, BPH monotherapy clinical studies and REDUCE study are as shown in the table below.
In addition the undesirable effects for tamsulosin below are based on information available in the public domain. The frequencies of adverse events may increase when the combination therapy is used.
The frequency of adverse reactions identified from clinical trials: Common; ≥1/100 to <1/10, Uncommon; ≥1/1000 to <1/100, Rare; ≥1/10,000 to <1/1000, Very rare; <1/10,000. Within each SOC grouping, undesirable effects are presented in order of decreasing seriousness. (See Table 2.)

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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).
Post marketing Data: Adverse events from world-wide post-marketing experience are identified from spontaneous post-marketing reports; therefore the true incidence is not known.
Dutasteride: Immune system disorders: Not known: Allergic reactions, including rash, pruritus, urticaria, localised oedema, and angioedema.
Psychiatric disorders: Not known: Depression.
Skin and subcutaneous tissue disorders: Uncommon: Alopecia (primarily body hair loss), hypertrichosis.
Reproductive system and breast disorders: Not known: Testicular pain and testicular swelling.
Tamsulosin: During postmarketing surveillance, reports of Intraoperative Floppy Iris Syndrome (IFIS), a variant of small pupil syndrome, during cataract surgery have been associated with alpha₁-adrenoceptor antagonists, including tamsulosin (see Precautions).
In addition atrial fibrillation, arrhythmia, tachycardia, dyspnoea, epistaxis, vision blurred, visual impairment, erythema multiforme, dermatitis exfoliative, ejaculation disorder, retrograde ejaculation, ejaculation failure and dry mouth have been reported in association with tamsulosin use. The frequency of events and the role of tamsulosin in their causation cannot be reliably determined.