Tamsulosin + Finasteride Tablets

Mechanism

Tamsulosin is a blocker of alpha-1A and alpha-1D adrenoceptors. 70% of the alpha-1 adrenoceptors in the prostate are of the alpha-1A subtype. By blocking these adrenoceptors, smooth muscle in the prostate is relaxed and urinary flow is improved. The blocking of alpha-1D adrenoceptors relaxes the detrusor muscles of the bladder which prevents storage symptoms. The specificity of tamsulosin focuses the effects to the target area while minimizing effects in other areas. Finasteride acts as a competitive and specific inhibitor of Type II 5α-reductase, a nuclear-bound steroid intracellular enzyme primarily located in the prostatic stromal cell that converts the androgen testosterone into the more active metabolite, 5α-dihydrotestosterone (DHT).1 DHT is considered to be the primary androgen playing a role in the development and enlargement of the prostate gland. It serves as the hormonal mediator for the hyperplasia upon accumulation within the prostate gland.DHT displays a higher affinity towards androgen receptors in the prostate gland compared to testosterone and by acting on the androgen receptors, DHT modulates genes that are responsible for cell proliferation.

Pharmacokinetics

• Absorption: Tamsulosin is well absorbed orally; Finasteride has good oral bioavailability.
• Distribution: Both drugs are highly protein bound.
• Metabolism: Tamsulosin via CYP3A4/CYP2D6; Finasteride via CYP3A4.
• Elimination: Tamsulosin via urine/feces; Finasteride via urine and feces.
• Half-life: Tamsulosin ≈ 9–13 hours; Finasteride ≈ 6 hours.

Side Effects

• Dizziness
• Orthostatic hypotension
• Decreased libido
• Erectile dysfunction
• Ejaculation disorders
• Breast tenderness or enlargement

Contraindication

• Hypersensitivity to Tamsulosin, Finasteride, or excipients
• Women and children — contraindicated
• Pregnancy — Finasteride can cause fetal harm
• Severe hepatic impairment

Interaction

• CYP3A4 inhibitors: Increase levels of both drugs (e.g., ketoconazole).
• Antihypertensives: Additive hypotensive effect with Tamsulosin.
• PDE‑5 inhibitors: Risk of severe hypotension.
• Warfarin: Monitor INR when co‑administered.

Warning and Precautions

• Monitor blood pressure regularly.
• Advise patients to rise slowly from sitting/lying positions.
• Women who are pregnant should not handle crushed/broken tablets.
• Monitor liver function during therapy.
• Finasteride may reduce PSA levels — adjust interpretation accordingly.