By David Douglas
NEW YORK (Reuters Health) Feb 25 - Limited evidence suggests that combination therapy including 5 alpha-reductase (5AR) inhibitors may alleviate lower urinary tract symptoms (LUTS) in men, according to a review by US and European researchers.
"In contrast to what some might believe," Dr. Kevin T. McVary told Reuters Health by email, "the number of adequate clinical trials assessing male LUTS combination therapy is surprisingly low. Alpha1-blocker / 5AR inhibitor is the best examined combination therapy for male LUTS and has sufficient scientific proof to be recommended for certain (not all) men suffering from LUTS."
In a January 25th online paper in European Urology, Dr. McVary of Southern Illinois University School of Medicine, Springfield, and colleagues note that although several drugs are approved for treatment of LUTS, monotherapy is generally used.
To assess whether combination therapy targeting different aspects of the condition might be helpful, the researchers examined data from 49 papers published between 1998 and 2012.
The most data were available on results of alpha1-blocker/ 5AR inhibitor combinations and in particular the researchers examined outcome in five studies involving more than 9,000 patients.
When given for more than a year to patients whose prostate volume was between 30 and 40 mL, several outcomes including American Urological Association symptom score were improved. At less than a year, the combination was no better than alpha1-blockers alone.
The researchers also note that there was a slightly increased rate of adverse events with the combination. Safety and efficacy have not been studied beyond six years.
The team also examined outcomes in eight studies with more than 5,000 patients, who were given alpha1-blocker and antimuscarinic combinations used either from the start or with the antimuscarinic as an add-on.
Because of heterogeneous study populations and different study designs, the data were inconsistent, according to the researchers. The approach may be safe and of value in men with a postvoid residual volume of less than 200 mL. But the team stresses that safety and efficacy have not been established beyond four months.
Another combination, that of alpha1-blockers with phosphodiesterase type 5 inhibitors, had data available only from a meta-analysis of small clinical pilot studies. Thus, say the investigators, "More studies are needed before definitive conclusions can be drawn."
Overall, it appears that patients with an enlarged prostate and who are at high risk for disease progression benefit most from the alpha1-blocker / 5AR inhibitor combination. Nevertheless, Dr. McVary concluded that "Acceptability and tolerance as well as costs remain an issue."
Eur Urol 2013.