Pharmacology Update
Dutasteride and Tamsulosin HCl Capsules (Jalyn)
By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD. Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; and Assistant Professor of Medicine, University of California, San Francisco. Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA. Drs. Elliott and Chan report no financial relationship to this field of study.
The FDA has approved the combination of dutasteride (DUT) and tamsulosin (TAM) in a single capsule. Dutasteride is a 5-a reductase inhibitor and tamsulosin is an a-adrenergic antagonist. The combination is marketed by GlaxoSmithKline as Jalyn.
Indications
DUT/TAM is indicated for the treatment of symptomatic benign prostate hyperplasia (BPH) in men with an enlarged prostate.1
Dosage
The recommended dose is one capsule taken daily 30 minutes after the same meal each day.1 The capsule should be swallowed whole and not chewed or opened.
Each capsule contains dutasteride 0.5 mg and tamsulosin 0.4 mg.
Potential Advantages
The capsule provides two drugs for BPH with different mechanisms of action in a single capsule. Dutasteride reduced the risk of prostate cancer (relative risk reduction of 22.8%; 95% confidence interval [CI], 15.2-29.8) over a 4-year study period.2
Potential Disadvantages
Early-onset (i.e., first 6 months) ejaculation disorders appear more common with DUT/TAM (7.6%) than either alone (1.1% and 2.2%).1 However the incidence was less than or equal to 0.1% at 19-24 months of therapy. DUT/TAM was primarily tested in Caucasians (88%) and the benefit in other ethnic populations, particularly African Americans, is not known.1
Comments
Dutasteride is an inhibitor of both type 1 and type 2 5-a reductase, in contrast to finasteride which is a type 2 inhibitor. Tamsulosin is a competitive inhibitor of a1A adrenergic receptors, which is predominately found in the prostate.3 It is suggested that dutasteride prevents prostate growth that would occur with TAM monotherapy, thus maintaining the effect of the latter.
The efficacy of DUT/TAM was supported by a 4-year, randomized, double-blind, parallel group study (CombAT Study). Subjects with BPH, at least 50 years of age, serum PSA greater than 1.5 ng/mL but less than 10 ng/mL, International Prostate Symptom Score (IPSS) ≥ 12, and enlarged prostate (≥ 30 cc) were randomized to DUT/TAM (n = 1610), dutasteride alone (n = 1623), or tamsulosin alone (n = 1611). The primary endpoint was the change in IPSS. The changes at 24 months were -6.2 ± 7.14, -4.9 ± 6.81, and -4.3 ± 7.01 for DUT/TAM, DUT, and TAM, respectively. The mean differences were statistically significant between each monotherapy compared to the combination (P < 0.001). Difference was observed at month 9. These represent a 37%, 30%, and 26% decrease from baseline scores. There was also an improvement in maximum urine flow rate of 2.4 mL/sec for DUT/TAM, 1.9 mL/sec for DUT, and 0.9 mL/sec for TAM. Difference was observed by month 6. Sixty-six percent of subjects completed the 48-month visit. DUT/TAM was superior to TAM but not DUT in reducing the risk of acute urinary retention or BPH-related surgery.4 However the combination was better than either monotherapy in time to first clinical progression of BPH (e.g., symptom deterioration) and change in IPSS. The superiority of DUT/TAM was observed from month 9 compared to TAM and month 3 compared to DUT.
Patient-reported quality of life and treatment satisfaction was in favor of DUT/TAM.5 Drug-related adverse events were higher with DUT/TAM (28%) compared to DUT (21%) and TAM (19%); however, withdrawal rates were similar (6%, 4%, and 4%, respectively). In a post-hoc analysis among Asian men with moderate-to-severe BPH (n = 325), the combination achieved benefit over tamsulosin monotherapy but was not statistically better than dutasteride.6
Clinical Implications
BPH is a common condition in older men that leads to lower urinary tract symptoms, urinary tract infection, and acute urinary retention. Pharmacotherapy includes an a-adrenergic receptor antagonist, 5-a reductase inhibitor, or a combination. The combination is generally more effective than monotherapy with either drug. Jalyn provides the combination of DUT and TAM in one capsule.
References
1. Jalyn Product Information. Research Triangle Park, NC: GlaxoSmithKline; June 2010.
2. Andriole GL, et al. Effect of dutasteride on the risk of prostate cancer. N Engl J Med 2010;362:1192-1202.
3. Miller J, Tarter TH. Combination therapy with duta-steride and tamsulosin for the treatment of sympto-matic enlarged prostate. Clin Interv Aging 2009;4:251-258.
4. Roehrborn CG, et al. The effects of combination therapy with dutasteride and tamsulosin on clinical outcomes in men with symptomatic benign prostatic hyperplasia: 4-year results from the CombAT study. Eur Urol 2010;57:123-131.
5. Montorsi F, et al. Effect of dutasteride, tamsulosin and the combination on patient-reported quality of life and treatment satisfaction in men with moderate-to-severe benign prostatic hyperplasia: 4-year data from the CombAT study. Int J Clin Pract 2010;64:1042-1051.
6. Chung BH, et al. Efficacy and safety of dutasteride, tamsulosin and their combination in a subpopulation of the CombAT study: 2-year results in Asian men with moderate-to-severe BPH. Prostate Cancer Prostatic Dis 2009;12:152-159.
The FDA has approved the combination of dutasteride (DUT) and tamsulosin (TAM) in a single capsule. Dutasteride is a 5-a reductase inhibitor and tamsulosin is an a-adrenergic antagonist. The combination is marketed by GlaxoSmithKline as Jalyn™.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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