INTRODUCTION
International continence society had divided OABS into storage, voiding
and post micturition symptoms based on their aetiological factors in
which overactive bladder symptoms (OABS) was defined as urgency with or
without urge incontinence usually with increased frequency and nocturia
without any proven infection or obvious pathology. OABS frequently
overlap with storage LUTS induced by similar patho-physiological
causes1 . In older men, BPH with LUTS and
chronic obstruction induces changes in detrusor muscle culminating in
detrusor over activity and inappropriate detrusor contractions during
the storage phase of the micturition producing
OABS2 . Around 50-75% of elderly male
patients of BPH with LUTS appear to have predominant/coexisting
OABS3 . Thus there exists a common unifying
factor amongst BPH, LUTS and OABS with the common denominator being an
inability to accommodate progressively increased bladder filling and
sensation inducing secondary OABS.
Traditionally antimuscarinic drugs were the main stay of therapy for
‘BPH induced OABS’ albeit accompanied by bothersome adverse events like
dry mouth, constipation and urinary retention leading to significant
drug discontinuity4 . Mirabegron is a newer
selective beta-3 agonist that has been tried in combination with α-1
blockers for alleviating ‘BPH induced OABS’ that act by relaxing the
bladder detrusor in the storage phase thereby increasing its storage
capacity and ameliorating OABS5, 6 . Some
studies have documented the efficacy of Mirabegron as an add on (post
alpha blocker therapy) managing residual storage LUTS in BPH patients
with co-existing residual OABS8,9 . Herein we
attempt to analyse the efficacy and safety of combination therapy
(Mirabegron 50mg + tamsulosin0.4mg) in de novo select patients of BPH
with predominantly coexisting OABS without prior alpha blockers run in
therapy.