February 7, 2016
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Side Effects


Clinical Trials Experience

There have been no clinical trials conducted with JALYN; however, the clinical efficacy and safety of coadministered dutasteride and tamsulosin, which are individual components of JALYN, have been evaluated in a multicenter, randomized, double-blind, parallel group trial (the Combination with Alpha-Blocker Therapy, or CombAT, trial). Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trial of another drug and may not reflect the rates observed in practice.

  • The most common adverse reactions reported in subjects receiving coadministered dutasteride and tamsulosin were impotence, decreased libido, breast disorders (including breast enlargement and tenderness), ejaculation disorders, and dizziness. Ejaculation disorders occurred significantly more in subjects receiving coadministration therapy (11%) compared with those receiving dutasteride (2%) or tamsulosin (4%) as monotherapy.
  • Trial withdrawal due to adverse reactions occurred in 6% of subjects receiving coadministered dutasteride and tamsulosin and in 4% of subjects receiving dutasteride or tamsulosin as monotherapy. The most common adverse reaction in all treatment arms leading to trial withdrawal was erectile dysfunction (1% to 1.5%).

In the CombAT trial, over 4,800 male subjects with BPH were randomly assigned to receive 0.5 mg dutasteride, 0.4 mg tamsulosin hydrochloride, or coadministration therapy (0.5 mg dutasteride and 0.4 mg tamsulosin hydrochloride) administered once daily in a 4-year double-blind trial. Overall, 1,623 subjects received monotherapy with dutasteride; 1,611 subjects received monotherapy with tamsulosin; and 1,610 subjects received coadministration therapy. The population was aged 49 to 88 years (mean age: 66 years) and 88% were Caucasian. Table 1 summarizes adverse reactions reported in at least 1% of subjects receiving coadminstration therapy and at a higher incidence than subjects receiving either dutasteride or tamsulosin as monotherapy.

Table 1: Adverse Reactions Reported Over a 48-Month Period in ≥ 1% of Subjects and More Frequently in the Coadministration Therapy Group Than the Dutasteride or Tamsulosin Monotherapy Group (CombAT) by Time of Onset

Adverse Reaction Adverse Reaction Time of Onset
Year 1 Year 2 Year 3 Year 4
Months 0-6 Months 7-12
Coadministrationa (n = 1,610) (n = 1,527) (n = 1,428) (n = 1,283) (n = 1,200)
Dutasteride (n = 1,623) (n = 1,548) (n = 1,464) (n = 1,325) (n = 1,200)
Tamsulosin (n = 1,611) (n = 1,545) (n = 1,468) (n = 1,281) (n = 1,112)
Ejaculation disordersb,c
Coadministration 7.8% 1.6% 1.0% 0.5% < 0.1%
Dutasteride 1.0% 0.5% 0.5% 0.2% 0.3%
Tamsulosin 2.2% 0.5% 0.5% 0.2% 0.3%
Coadministration 5.4% 1.1% 1.8% 0.9% 0.4%
Dutasteride 4.0% 1.1% 1.6% 0.6% 0.3%
Tamsulosin 2.6% 0.8% 1.0% 0.6% 1.1%
Decreased libidoc,d
Coadministration 4.5% 0.9% 0.8% 0.2% 0.0%
Dutasteride 3.1% 0.7% 1.0% 0.2% 0.0%
Tamsulosin 2.0% 0.6% 0.7% 0.2% < 0.1%
Breast disordersf
Coadministration 1.1% 1.1% 0.8% 0.9% 0.6%
Dutasteride 0.9% 0.9% 1.2% 0.5% 0.7%
Tamsulosin 0.4% 0.4% 0.4% 0.2% 0.0%
Coadministration 1.1% 0.4% 0.1% < 0.1% 0.2%
Dutasteride 0.5% 0.3% 0.1% < 0.1% < 0.1%
Tamsulosin 0.9% 0.5% 0.4% < 0.1% 0.0%
a Coadministration = AVODART® 0.5 mg once daily plus tamsulosin 0.4 mg once daily.
b Includes anorgasmia, retrograde ejaculation, semen volume decreased, orgasmic sensation decreased, orgasm abnormal, ejaculation delayed, ejaculation disorder, ejaculation failure, and premature ejaculation.
c These sexual adverse reactions are associated with dutasteride treatment (including monotherapy and combination with tamsulosin). These adverse reactions may persist after treatment discontinuation. The role of dutasteride in this persistence is unknown.
d Includes erectile dysfunction and disturbance in sexual arousal.
e Includes libido decreased, libido disorder, loss of libido, sexual dysfunction, and male sexual dysfunction.
f Includes breast enlargement, gynecomastia, breast swelling, breast pain, breast tenderness, nipple pain, and nipple swelling.

Cardiac Failure

In CombAT, after 4 years of treatment, the incidence of the composite term cardiac failure in the coadministration group (12/1,610; 0.7%) was higher than in either monotherapy group: dutasteride, 2/1,623 (0.1%) and tamsulosin, 9/1,611 (0.6%). Composite cardiac failure was also examined in a separate 4-year placebo-controlled trial evaluating dutasteride in men at risk for development of prostate cancer. The incidence of cardiac failure in subjects taking dutasteride was 0.6% (26/4,105) compared with 0.4% (15/4,126) in subjects on placebo. A majority of subjects with cardiac failure in both trials had comorbidities associated with an increased risk of cardiac failure. Therefore, the clinical significance of the numerical imbalances in cardiac failure is unknown. No causal relationship between dutasteride alone or coadministered with tamsulosin and cardiac failure has been established. No imbalance was observed in the incidence of overall cardiovascular adverse events in either trial.

Additional information regarding adverse reactions in placebo-controlled trials with dutasteride or tamsulosin monotherapy follows:


Long-Term Treatment (Up to 4 Years): High-Grade Prostate Cancer: The REDUCE trial was a randomized, double-blind, placebo-controlled trial that enrolled 8,231 men aged 50 to 75 years with a serum PSA of 2.5 ng/mL to 10 ng/mL and a negative prostate biopsy within the previous 6 months. Subjects were randomized to receive placebo (N = 4,126) or 0.5-mg daily doses of dutasteride (N = 4,105) for up to 4 years. The mean age was 63 years and 91% were Caucasian. Subjects underwent protocol-mandated scheduled prostate biopsies at 2 and 4 years of treatment or had “for-cause biopsies” at non-scheduled times if clinically indicated. There was a higher incidence of Gleason score 8-10 prostate cancer in men receiving dutasteride (1.0%) compared with men on placebo (0.5%) [see INDICATIONS AND USAGE, WARNINGS AND PRECAUTIONS]. In a 7-year placebo-controlled clinical trial with another 5 alpha-reductase inhibitor (finasteride 5 mg, PROSCAR), similar results for Gleason score 8-10 prostate cancer were observed (finasteride 1.8% versus placebo 1.1%).

No clinical benefit has been demonstrated in patients with prostate cancer treated with dutasteride.

Reproductive and Breast Disorders

In the 3 pivotal placebo-controlled BPH trials with dutasteride, each 4 years in duration, there was no evidence of increased sexual adverse reactions (impotence, decreased libido, and ejaculation disorder) or breast disorders with increased duration of treatment. Among these 3 trials, there was 1 case of breast cancer in the dutasteride group and 1 case in the placebo group. No cases of breast cancer were reported in any treatment group in the 4-year CombAT trial or the 4-year REDUCE trial.

The relationship between long-term use of dutasteride and male breast neoplasia is currently unknown.


According to the tamsulosin prescribing information, in two 13-week treatment trials with tamsulosin monotherapy, adverse reactions occurring in at least 2% of subjects receiving 0.4 mg tamsulosin hydrochloride and at an incidence higher than in subjects receiving placebo were: infection, asthenia, back pain, chest pain, somnolence, insomnia, rhinitis, pharyngitis, cough increased, sinusitis, and diarrhea.

Signs and Symptoms of Orthostasis: According to the tamsulosin prescribing information, in clinical trials with tamsulosin monotherapy, a positive orthostatic test result was observed in 16% (81/502) of subjects receiving 0.4 mg tamsulosin hydrochloride versus 11% (54/493) of subjects receiving placebo. Because orthostasis was detected more frequently in the tamsulosin-treated subjects than in placebo recipients, there is a potential risk of syncope [see WARNINGS AND PRECAUTIONS].

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of the individual components of JALYN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. These reactions have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to drug exposure.


Immune System Disorders: Hypersensitivity reactions, including rash, pruritus, urticaria, localized edema, serious skin reactions, and angioedema.

Neoplasms: Male breast cancer.

Psychiatric Disorders: Depressed mood.

Reproductive System and Breast Disorders: Testicular pain and testicular swelling.


Immune System Disorders: Hypersensitivity reactions, including rash, urticaria, pruritus, angioedema, and respiratory problems have been reported with positive rechallenge in some cases.

Cardiac Disorders: Palpitations, dyspnea, atrial fibrillation, arrhythmia, and tachycardia.

Skin Disorders: Skin desquamation, including Stevens-Johnson syndrome.

Gastrointestinal Disorders: Constipation, vomiting.

Reproductive System and Breast Disorders: Priapism.

Vascular Disorders: Hypotension.

Ophthalmologic Disorders: During cataract surgery, a variant of small pupil syndrome known as Intraoperative floppy iris syndrome (IFIS) associated with alpha adrenergic antagonist therapy [see WARNINGS AND PRECAUTIONS].

Read the Jalyn (dutasteride and tamsulosin hydrochloride capsules) Side Effects Center for a complete guide to possible side effects


There have been no drug interaction trials using JALYN. The following sections reflect information available for the individual components.

Cytochrome P450 3A Inhibitors


Dutasteride is extensively metabolized in humans by the CYP3A4 and CYP3A5 isoenzymes. The effect of potent CYP3A4 inhibitors on dutasteride has not been studied. Because of the potential for drug-drug interactions, use caution when prescribing a dutasteride-containing product, including JALYN, to patients taking potent, chronic CYP3A4 enzyme inhibitors (e.g., ritonavir) [see CLINICAL PHARMACOLOGY].


Strong and Moderate Inhibitors of CYP3A4 or CYP2D6: Tamsulosin is extensively metabolized, mainly by CYP3A4 or CYP2D6.

Concomitant treatment with ketoconazole (a strong inhibitor of CYP3A4) resulted in increases in the Cmax and AUC of tamsulosin by factors of 2.2 and 2.8, respectively. Concomitant treatment with paroxetine (a strong inhibitor of CYP2D6) resulted in increases in the Cmax and AUC of tamsulosin by factors of 1.3 and 1.6, respectively. A similar increase in exposure is expected in poor metabolizers (PM) of CYP2D6 as compared to extensive metabolizers (EM). Since CYP2D6 PMs cannot be readily identified and the potential for significant increase in tamsulosin exposure exists when tamsulosin 0.4 mg is coadministered with strong CYP3A4 inhibitors in CYP2D6 PMs, tamsulosin 0.4 mg capsules should not be used in combination with strong inhibitors of CYP3A4 (e.g., ketoconazole). The effects of coadministration of both a CYP3A4 and a CYP2D6 inhibitor with tamsulosin have not been evaluated. However, there is a potential for significant increase in tamsulosin exposure when tamsulosin 0.4 mg is coadministered with a combination of both CYP3A4 and CYP2D6 inhibitors [see WARNINGS AND PRECAUTIONS, CLINICAL PHARMACOLOGY].

Cimetidine: Treatment with cimetidine resulted in a moderate increase in tamsulosin hydrochloride AUC (44%) [see WARNINGS AND PRECAUTIONS, CLINICAL PHARMACOLOGY].



Concomitant administration of dutasteride 0.5 mg/day for 3 weeks with warfarin does not alter the steady-state pharmacokinetics of the S- or R-warfarin isomers or alter the effect of warfarin on prothrombin time [see CLINICAL PHARMACOLOGY].


A definitive drug-drug interaction trial between tamsulosin hydrochloride and warfarin was not conducted. Results from limited in vitro and in vivo studies are inconclusive. Caution should be exercised with concomitant administration of warfarin and tamsulosin-containing products, including JALYN [see WARNINGS AND PRECAUTIONS, CLINICAL PHARMACOLOGY].

Nifedipine, Atenolol, Enalapril


Dosage adjustments are not necessary when tamsulosin is administered concomitantly with nifedipine, atenolol, or enalapril [see CLINICAL PHARMACOLOGY].

Digoxin and Theophylline


Dutasteride does not alter the steady-state pharmacokinetics of digoxin when administered concomitantly at a dose of 0.5 mg/day for 3 weeks [see CLINICAL PHARMACOLOGY].


Dosage adjustments are not necessary when tamsulosin is administered concomitantly with digoxin or theophylline [see CLINICAL PHARMACOLOGY].



Tamsulosin had no effect on the pharmacodynamics (excretion of electrolytes) of furosemide. While furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride Cmax and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the dose of tamsulosin [see CLINICAL PHARMACOLOGY].

Calcium Channel Antagonists


Coadministration of verapamil or diltiazem decreases dutasteride clearance and leads to increased exposure to dutasteride. The change in dutasteride exposure is not considered to be clinically significant. No dosage adjustment of dutasteride is recommended [see CLINICAL PHARMACOLOGY].



Administration of a single 5-mg dose of dutasteride followed 1 hour later by a 12-g dose of cholestyramine does not affect the relative bioavailability of dutasteride [see CLINICAL PHARMACOLOGY].

Read the Jalyn Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 5/13/2013

Side Effects

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