Immunohistochemical Distribution of cAMP- and cGMP-Phosphodiesterase (PDE) Isoenzymes in the Human Prostate

Combination of alfuzosin and sildenafil is superior to monotherapy in treating lower urinary tract symptoms and erectile dysfunction

OBJECTIVES

This pilot study was undertaken to assess the efficacy and safety of the alpha(1)-blocker alfuzosin 10mg once daily (OD), the PDE-5 inhibitor sildenafil 25mg OD, and the combination of both on lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) and erectile dysfunction (ED).

MATERIAL AND METHODS

Men aged 50-76 yr with previously untreated LUTS and ED were randomized to receive alfuzosin (n=20), sildenafil (n=21), or the combination of both (n=21) for 12 wk. Changes from baseline in International Prostate Symptom Score (IPSS), voiding diary, maximum urinary flow rate (Qmax), postvoid residual urine (PVRU) volume, and erectile function domain of the International Index of Erectile Function (IIEF) were assessed at week 12.

RESULTS

Improvement of IPSS was significant with the three treatments but greatest with the combination (-24.1%) compared with alfuzosin (-15.6%) and sildenafil (-11.8%) [corrected] alone (p<0.03). Frequency, nocturia, PVR, and Qmax were significantly improved with alfuzosin only and the combination. Improvement in IIEF was slight with alfuzosin (16.7%), marked with sildenafil (49.7%), and greatest with the combination (58.6%). Likewise, increases in the frequency of penetration (Q3) and of maintained erection (Q4) were greater with the combination therapy (65.2% and 68.2%, respectively) than with sildenafil (41.7% and 59.1%, respectively) and alfuzosin (27.3% and 33.3%, respectively) alone. All three treatments were well tolerated.

CONCLUSIONS

In this pilot study, the combination of alfuzosin 10 mg OD and sildenafil 25 mg OD is safe and more effective than monotherapy with either agent to improve both voiding and sexual dysfunction in men with LUTS suggestive of BPH.

Phosphodiesterase type 5 inhibitors: the day after

OBJECTIVE

Review the literature on phosphodiesterase type 5 inhibitors (PDE5-Is), addressing critical issues in their current and future use, assessing unanswered questions, and identifying research needs.

METHODS

A MEDLINE search was conducted on PDE5-Is, with emphasis on clinical trials and experience, for interpretation and analysis of their present and future role.

RESULTS

Although approximately 40 million patients with erectile dysfunction have been treated successfully worldwide with the three available PDE5-Is, inappropriate instructions, lack of follow-up, and lack of patient-centered care models are the main reasons for "non-response," leading to drop-out rates of >50%. Patients with severe neurologic damage, diabetes mellitus, or severe vascular disease may be resistant to PDE5-Is. Preservation of corporal smooth muscle with chronic administration of PDE5-Is has been reported and substantial evidence indicates that these drugs have beneficial effects on endothelium and cardiovascular function; sildenafil has been approved for the treatment of idiopathic pulmonary hypertension. Improvement of lower urinary tract symptoms in men with benign prostatic hyperplasia after PDE5-I administration has been also suggested.

CONCLUSIONS

The data indicate the necessity for (1) exploration of the pharmacologic characteristics of the three PDE5-Is; (2) research on their pharmacologic differences because some actions seems to be drug-specific; (3) development of alternative management strategies, such as chronic, low, everyday doses of PDE5-Is, if the monthly cost is affordable; and (4) clinical trials on use of PDE5-Is to treat other chronic conditions. The door for innovative therapeutic approaches will open, specifically for cross-risk factor treatment with PDE5-Is or their use in combination treatments or new multimodal pills that take advantage of drugs that exert pleiotropic vascular actions.

Semiquantitative imaging measurement of baseline and vasomodulated normal prostatic blood flow using sildenafil

The physiologic variability of blood flow to the prostate has not been studied until this time. We report the vasoactive effects of sildenafil and phenylephrine on blood flow of the normal prostate. Sildenafil increases prostate blood flow by approximately 75% and phenylephrine reduces the flow incrementally. Administration of these drugs with dynamic contrast-enhanced magnetic resonance imaging may improve the diagnosis of cancerous tissue because according to the literature, tumor angiogenic vessels lack the vasoactive physiologic response of the normal tissue.