Finasteride Vs. Flomax: Drug Comparison

Finasteride is the active ingredient in the brand-name medication Proscar^®. The information below is about brand name Proscar. According to the FDA, “Generic medicines use the same active ingredients as brand-name medicines and work the same way, so they have the same risks and benefits as the brand-name medicines.”

Proscar (finasteride) is an oral medication used primarily to treat benign prostatic hyperplasia (BPH), a condition characterized by an enlarged prostate. By inhibiting the enzyme 5α-reductase, Proscar reduces the levels of dihydrotestosterone (DHT), which is responsible for prostate growth. This helps alleviate symptoms of BPH such as difficulty in urinating, reduced urine flow, and the need to urinate frequently or urgently. Proscar is taken once daily and may also help reduce the need for surgery related to BPH. However, it can cause side effects such as decreased libido, erectile dysfunction, and breast tenderness​.

Flomax^® (tamsulosin hydrochloride) is a medication commonly prescribed to treat benign prostatic hyperplasia (BPH), a condition characterized by an enlarged prostate. It works by relaxing the muscles in the prostate and bladder neck, making it easier to urinate and relieving symptoms such as difficulty starting urination, weak stream, and the need to urinate frequently or urgently. Flomax is typically taken once daily, about 30 minutes after the same meal each day. Common side effects include dizziness, runny nose, and ejaculation problems. Flomax should be used with caution in patients with a history of low blood pressure.

5α-reductase inhibitor

Alpha-1 adrenoceptor antagonist

Proscar (finasteride) is indicated:

• For the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to:

  • Improve symptoms

  • Reduce the risk of acute urinary retention

  • Reduce the risk of the need for surgery including transurethral resection of the prostate (TURP) and prostatectomy

Proscar (finasteride) administered in combination with the alpha-blocker doxazosin is indicated:

• To reduce the risk of symptomatic progression of BPH (a confirmed ≥4 point increase in American Urological Association [AUA] symptom score)

Flomax (tamsulosin hydrochloride) is indicated to treat:

• The signs and symptoms of benign prostatic hyperplasia (BPH)

• Typically taken orally once daily

• Comes in 5 mg tablets

• Typically taken orally once daily

• Comes in 0.4 mg capsules

The drug-related adverse reactions, reported in ≥1% in patients treated with Proscar and greater than in patients treated with placebo over a 4-year study are:

• Erectile dysfunction

• Decreased libido

• Decreased volume of ejaculate

• Breast enlargement

• Breast tenderness and rash

The most common adverse events (≥2% of patients and at a higher incidence than placebo) with the 0.4 mg dose or 0.8 mg dose were:

• Headache

• Dizziness

• Nasal congestion

• Infection

• Abnormal ejaculation

• Weakness

• Back pain

• Diarrhea

• Sore throat

• Chest pain

• Cough increased

• Somnolence

• Nausea

• Inflammation of the sinuses

• Insomnia

• Libido decreased

• Tooth disorder

• Blurred vision

• Hypersensitivity to any components of this product

• Females who are or may potentially be pregnant

• Contraindicated in patients known to be hypersensitive to tamsulosin hydrochloride or any component of Flomax capsules

• Drug interactions: Strong inhibitors of CYP3A4 (e.g., ketoconazole), moderate inhibitors of CYP3A4 (e.g., erythromycin), strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, patients known to be CYP2D6 poor metabolizers, PDE5 inhibitors

• Proscar reduces serum prostate specific antigen (PSA) levels by approximately 50%. However, any confirmed increase in PSA while on Proscar may signal the presence of prostate cancer and should be evaluated, even if those values are still within the normal range for men not taking a 5α-reductase inhibitor

• Proscar may increase the risk of high-grade prostate cancer

• Females should not handle crushed or broken Proscar tablets when they are pregnant or may potentially be pregnant due to potential risk to a male fetus

• Proscar is not indicated for use in pediatric patients or females

• Prior to initiating treatment with Proscar for BPH, consideration should be given to other urological conditions that may cause similar symptoms

• Postural low blood pressure

• Should not be used in combination with strong inhibitors of CYP3A4. Use with caution in combination with moderate inhibitors of CYP3A4, with strong or moderate inhibitors of CYP2D6, in patients known to be CYP2D6 poor metabolizers, or in combination with other cytochrome P450 inhibitors

• Should not be used in combination with other alpha adrenergic blocking agents

• Exercise caution with concomitant administration of warfarin

• Possibility of prolonged erection

• Intraoperative floppy iris syndrome has been observed during cataract and glaucoma surgery in some patients

• Be screened for the presence of prostate cancer prior to treatment and at regular intervals afterwards

*This information is from the label for brand name Proscar^®. See the Full Prescribing Information for more complete information. Finasteride, the active ingredient in Proscar, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient finasteride.

*This information is from the label for brand name Flomax^®. See the Full Prescribing Information for more complete information. Tamsulosin, the active ingredient in Flomax, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient tamsulosin.