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5-Alpha Reductase Inhibitor/Alpha-1 Blocker Combination/Prescription

JALYN

JALYN

Clinical safety rating

caution

Comprehensive clinical and safety monograph for JALYN (JALYN).


Mechanism of Action

Jalyn is a combination of dutasteride, a 5α-reductase inhibitor that inhibits the conversion of testosterone to dihydrotestosterone (DHT), and tamsulosin, an α1-adrenoceptor antagonist that relaxes smooth muscle in the prostate and bladder neck.

What the body does with it

MetabolismDutasteride is extensively metabolized by CYP3A4 and CYP3A5. Tamsulosin is extensively metabolized by CYP3A4 and CYP2D6.
ExcretionDutasteride: 40% renal, 60% fecal as metabolites; Tamsulosin: 76% renal (9% unchanged), 24% fecal as metabolites.
Half-lifeDutasteride: 5 weeks (t½ ∼3-5 weeks) due to high tissue binding and slow elimination; Tamsulosin: 9-13 hours (t½ ∼9-13 h) in healthy subjects, prolonged in elderly (∼14-15 h).
Protein bindingDutasteride: 99.0-99.5% bound to albumin and alpha-1-acid glycoprotein; Tamsulosin: 94-99% bound to alpha-1-acid glycoprotein.
Volume of DistributionDutasteride: 300-500 L (∼3-4 L/kg); Tamsulosin: 16 L (∼0.2 L/kg). Dutasteride’s large Vd indicates extensive tissue distribution.
BioavailabilityOral: Dutasteride ∼60% (capsule); Tamsulosin ∼90% (capsule, under fed conditions slightly reduced).
Onset of ActionOral: Symptom improvement begins within 1-2 weeks for tamsulosin (symptomatic relief) but BPH volume reduction with dutasteride requires 3-6 months.
Duration of ActionSymptomatic relief from tamsulosin lasts 24 hours with once-daily dosing; dutasteride effect persists for weeks after discontinuation due to long t½.
Molecular WeightDutasteride: 528.5 Da; Tamsulosin: 456.6 Da (as HCl salt); combination product: N/A as fixed-dose

Classification & Brands

Dosing & administration

1 capsule (0.5 mg dutasteride/0.4 mg tamsulosin) orally once daily, 30 minutes after the same meal each day.

Dosage formCAPSULE
Renal impairmentNo dose adjustment required for mild to moderate renal impairment (GFR ≥30 mL/min). Not recommended for severe renal impairment (GFR <30 mL/min) due to lack of data.
Liver impairmentContraindicated in severe hepatic impairment (Child-Pugh class C). No dose adjustment for mild to moderate impairment (Child-Pugh A or B), but use with caution.
Pediatric useNot indicated for use in pediatric patients. Safety and efficacy not established.
Geriatric useNo specific dose adjustment recommended based on age alone. Monitor for orthostatic hypotension, dizziness, and falls risk, especially in elderly patients. Consider underlying renal and hepatic function.

Use during pregnancy

1st trimesterContraindicated; risk of fetal hypotension, renal impairment, and oligohydramnios due to angiotensin II receptor blocker component (dutasteride/tamsulosin combination).
2nd trimesterContraindicated; same risks as t1 with additional risk of fetal skull hypoplasia.
3rd trimesterContraindicated; risk of neonatal renal failure and death.

Clinical note

Comprehensive clinical and safety monograph for JALYN (JALYN).

Placental transferDutasteride undergoes placental transfer in rats; tamsulosin is expected to cross the placenta based on molecular weight and animal data. In humans, angiotensin II receptor blockers are known to cross the placenta.
BreastfeedingExcretion into human milk unknown; due to potential for serious adverse reactions, breastfeeding is not recommended during therapy. Tamsulosin is excreted in rat milk; dutasteride is detected in human semen but not likely in milk.
Lactation RatingL5 (Contraindicated)
Teratogenic RiskJALYN (dutasteride/tamsulosin) is contraindicated in pregnancy. Dutasteride is a 5-alpha-reductase inhibitor that can inhibit dihydrotestosterone formation, potentially causing abnormal development of external genitalia in male fetuses. Tamsulosin is an alpha-1 blocker with limited data but potential risks. First trimester: avoid; second and third trimesters: avoid due to theoretical risk.
Fetal MonitoringNot applicable for JALYN use in women of childbearing potential. If inadvertent exposure during pregnancy occurs, monitor fetal growth and development, and assess for urogenital abnormalities in male fetuses.
Fertility EffectsDutasteride may impair male fertility by reducing sperm count and motility. Tamsulosin may cause ejaculatory dysfunction including retrograde ejaculation. Effects on female fertility are unknown because JALYN is not used in women.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

PregnancyWomen of childbearing potentialHypersensitivity to dutasteride, tamsulosin, or any componentHistory of orthostatic hypotensionSevere hepatic impairment

Clinical Precautions

PrecautionsUse with caution in combination with other alpha-blockers due to risk of hypotension, Postural hypotension may occur, especially at initiation of therapy, Not recommended for use in women, children, or adolescents due to teratogenic risk, Evaluate for prostate cancer before initiating therapy, Dutasteride may increase risk of high-grade prostate cancer in some studies, Hepatic impairment may alter metabolism of dutasteride
Food/DietaryAvoid grapefruit juice; may increase tamsulosin exposure and adverse effects. Administer with a meal (same meal consistency daily) to reduce tamsulosin-related adverse events. No other food interactions known.

Clinical Tips & Counseling

Clinical PearlsJalyn is a fixed-dose combination of dutasteride (5α-reductase inhibitor) and tamsulosin (α1-adrenergic antagonist) for symptomatic benign prostatic hyperplasia (BPH). Onset of symptom relief is faster than either agent alone. Tamsulosin component may cause orthostatic hypotension, especially in elderly patients; counsel to rise slowly. Dutasteride reduces serum prostate-specific antigen (PSA) by approximately 50% after 6 months; PSA levels should be interpreted accordingly. Avoid use in women of childbearing potential; dutasteride is teratogenic and can be absorbed through skin contact with capsules.
Patient AdviceTake Jalyn 30 minutes after the same meal each day to maintain consistent absorption. · Do not crush, chew, or open capsules; swallow whole. · Avoid grapefruit juice, which may increase tamsulosin levels. · Rise slowly from sitting or lying to prevent dizziness from low blood pressure. · Report symptoms like fainting, severe headache, or prolonged painful erection (priapism) immediately. · Do not donate blood during therapy and for 6 months after stopping due to dutasteride transfer risk. · Use reliable contraception if partner is of childbearing potential; dutasteride can cause fetal harm.

JALYN Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

External sources

DailyMed (NIH) PubMed OpenFDA