Recent research from Japan shows that treatment with naftopidil is effective in the long term for patients with benign prostatic hyperplasia. Older age, increased prostate volume, and elevated prostate-specific antigen at baseline can, however, cause the treatment to fail.
The study, “Three-year outcome analysis of alpha 1-blocker naftopidil for patients with benign prostatic hyperplasia in a prospective multicenter study in Japan,” was published in the journal Patient Preference and Adherence.
Benign prostatic hyperplasia (BPH) is a condition in which the prostate gland is enlarged but not cancerous. A common prostate problem for men older than age 50, it often appears as lower urinary tract symptoms, suggestive of BPH. Current treatments include the use of alpha1-adrenergic receptor (α1-AR) antagonists, leading to muscle relaxation and decreased resistance to urine flow.
Naftopidil, an α1D/A-adrenergic receptor antagonist, is among those with high affinity for a subtype of the adrenergic receptor.
Researchers prospectively analyzed the three-year outcomes of naftopidil treatment in BPH patients, including those who had dropped out of the study during follow-up but returned within three years. A total of 117 patients with BPH/LUTS, ages 50 or older and with international prostate symptom scores (IPSS) greater than or equal to 8, were enrolled in the prospective multicenter study conducted between July 2006 and January 2013.
After a three-year follow-up, researchers found that only 25 patients (21.4%) needed to continue to use naftopidil, with results showing improvement in total IPSS, maximum flow rate, quality of life index, and BPH problem index during the observed years. The remaining 92 patients (78.6%) either discontinued treatment due to for-cause termination (45 people or 38.5%) or stopped using the treatment during follow-up (47 patients or 40.2%).
Adverse events, mainly due to postural hypotension, were noted by 5% of patients who had stopped the medication. Of the patients who chose to discontinue naftopidil treatment during follow-up, only 13 (26%) said they needed to be re-treated with α1-blockers and/or surgery within three years.
Treatment failure was predicted by age, serum prostate-specific antigen, and prostate volume.
“This is the first study to prospectively evaluate the clinical courses of patients who received naftopidil for BPH/LUTS, including those who dropped out during follow-up. Data were also collected from the patients who quit medication at the time point scheduled as the final examination at 3 years,” the researchers wrote.
“Although the small number of patients enrolled and two initial dosage of naftopidil used are major limitations, the study provides information on the long-term clinical outcome of naftopidil monotherapy for patients with BPH/LUTS as well as risk factors for treatment failure,” they concluded.