Is it common to take Cardura (doxazosin) and Finasteride at the same time?

From the Guidelines

Yes, it is common to take Cardura (doxazosin) and finasteride at the same time for treating benign prostatic hyperplasia (BPH). This combination therapy is frequently prescribed because these medications work in complementary ways. Cardura is an alpha-blocker that relaxes the muscles in the prostate and bladder neck, providing relatively quick relief of urinary symptoms. Finasteride is a 5-alpha reductase inhibitor that shrinks the prostate gland over time by reducing levels of dihydrotestosterone (DHT), but typically takes 3-6 months to show full effects. When used together, Cardura provides immediate symptom relief while finasteride works on addressing the underlying prostate enlargement.

Key Points to Consider

• The typical dosing is 1-8 mg of Cardura once daily and 5 mg of finasteride once daily.
• This combination has been shown to be more effective than either medication alone for men with moderate to severe BPH symptoms and enlarged prostates 1.
• Patients should be aware that while Cardura may cause dizziness, especially when standing up quickly, finasteride can cause sexual side effects such as decreased libido or erectile dysfunction in some men.
• The combination of an alpha-adrenergic receptor blocker and a 5 alpha-reductase inhibitor has been found to be more effective in relieving and preventing the progression of symptoms than alpha-blocker monotherapy, especially in patients with larger glands and higher PSA values 1.
• The safety of specific combinations other than finasteride plus doxazosin, terazosin, and alfuzosin has not been assessed, but the best-tested combination is doxazosin and finasteride 1.

Important Considerations for Treatment

• Treatment with 5-ARIs and combination therapy hinges on prostate volume and PSA threshold; therefore, obtaining imaging with TRUS (or reviewing existing cross-sectional imaging) to objectively assess prostate size is reasonable, with reservation of 5-ARIs for those with appropriately enlarged glands 1.
• A minimum prostate volume of >30cc or PSA >1.5ng/mL is necessary for a reliable 5-ARI response, but the larger the gland, the more pronounced the effects 1.

From the FDA Drug Label

The Medical Therapy of Prostatic Symptoms (MTOPS) Trial was a double-blind, randomized, placebo-controlled, multicenter, 4- to 6-year study (average 5 years) in 3,047 men with symptomatic BPH, who were randomized to receive finasteride tablets 5 mg/day (n=768), doxazosin 4 or 8 mg/day (n=756), the combination of finasteride tablets 5 mg/day and doxazosin 4 or 8 mg/day (n=786), or placebo (n=737) for 4 to 6 years. Combination therapy with finasteride and doxazosin was associated with no new clinical adverse experience.

Yes, it is common to take Cardura (doxazosin) and Finasteride at the same time, as evidenced by the MTOPS study, which included a combination therapy group of 786 patients receiving both finasteride and doxazosin 2.

From the Research

Combination Therapy with Cardura (Doxazosin) and Finasteride

• The use of combination therapy with alpha-blockers (such as doxazosin) and 5-alpha reductase inhibitors (such as finasteride) is a common approach in the treatment of benign prostatic hyperplasia (BPH) 3, 4, 5.
• Studies have shown that combination therapy with doxazosin and finasteride can be effective in improving urinary symptoms and reducing the risk of BPH progression 3, 5.
• The Medical Therapy of Prostatic Symptoms (MTOPS) study found that combination therapy with doxazosin and finasteride was significantly more effective than either component alone in reducing BPH-related symptoms and lowering the rate of overall clinical progression 5.
• The efficacy of combination therapy was greatest in patients with an enlarged prostate, more severe symptoms, and higher prostate-specific antigen (PSA) levels 5.

Efficacy and Safety of Combination Therapy

• Combination therapy with doxazosin and finasteride has been shown to improve urinary symptoms and reduce the risk of BPH progression, with a significant reduction in the risk of acute urinary retention and surgical intervention 3, 5.
• The safety profile of combination therapy is generally favorable, with a lower risk of adverse events such as dizziness, postural hypotension, and asthenia compared to alpha-blocker monotherapy 3, 6.
• However, combination therapy may be associated with a higher risk of sexual health dysfunctions, such as impotence, erectile dysfunction, and decreased libido, compared to alpha-blocker monotherapy 3, 7.

Clinical Use of Combination Therapy

• Combination therapy with doxazosin and finasteride may be considered as a treatment option for patients with moderate to severe BPH symptoms, particularly those with an enlarged prostate and higher PSA levels 5.
• The decision to use combination therapy should be based on individual patient factors, including symptom severity, prostate size, and PSA levels, as well as the presence of any underlying medical conditions or concomitant medications 5.