Efficacy of Tadalafil/Solifenacin VS Tamsulosin/Solifenacin Combination Therapy for BPH/OAB

The investigators will compare the efficacy and safety of tadalafil/solifenacin combination therapy versus tamsulosin/solifenacin combination therapy for the treatment of BPH/OAB in a randomized controlled trial (RCT).

Benign prostatic hyperplasia (BPH) is one of the most commonly diagnosed diseases in aging men worldwide. It is commonly associated with bothersome lower urinary tract symptoms (LUTS) including voiding symptoms such as decreased force of stream, intermittent stream, hesitancy and sensation of incomplete bladder emptying and storage symptoms such as frequent urination, urgency and nocturia. LUTS especially storage symptoms interfere with the daily activities and adversely affect the quality of life (QoL).

Alpha-1 adrenergic receptor blockers have been used as a first-line treatment of LUTS suggestive of BPH (LUTS/BPH). Phosphodiesterase 5 inhibitors (tadalafil) have recently been used as initial treatment of LUTS/BPH. It was confirmed that once daily use of tadalafil 5 mg as a monotherapy is safe and has similar efficacy when compared to tamsulosin.

Combination therapy could be used in patients who have BPH with overactive bladder (BPH/OAB) and still have persistent storage symptoms despite α1- adrenergic blockers. Anticholinergics in combination with α1- adrenergic blockers have been reported to be effective in those patients. Moreover, it has been reported that tadalafil has similar efficacy and safety to solifenacin when used in combination with tamsulosin for patients with persistent storage symptoms refractory to α1- adrenergic blockers. In another study, tadalafil/mirabegron combination therapy was used for BPH/OAB and its effect appeared to be greater than the effect of tadalafil monotherapy. Also, the combination therapy of tadalafil and solifenacin was approved to achieve higher response than tadalafil monotherapy in improvement of persistent storage symptoms associated with BPH.

It was established that tadalafil can be used as a monotherapy to relieve both voiding and storage LUTS and it can be used in combination with tamsulosin or mirabegron to treat BPH/OAB. However, there is limited evidence regarding the efficacy and safety of the combined use of tadalafil and solifenacin for the treatment of BPH/OAB. Therefore, in this study, the investigators will compare the efficacy and safety of tadalafil/solifenacin combination therapy versus tamsulosin/solifenacin combination therapy for the treatment of BPH/OAB in a randomized controlled trial (RCT).

Eligibility Criteria:
Inclusion Criteria:

1. Ability to give informed consent and reply to questionnaires.
2. Age ≥ 45 years
3. IPSS ≥ 8
4. OABSS ≥ 5, urgency subscore ≥2

Exclusion Criteria:

1. Untreated urinary tract infection (UTI).
2. Postvoid residual (PVR) more than 150 mL
3. Neurogenic lower urinary tract dysfunction (LUTD).
4. Depression or any psychogenic disorders.
5. Diabetes mellitus, hypertension or severe cardiovascular disease.
6. Prior radiation therapy to the pelvic area.
7. Prostate cancer or bladder tumor.
8. Past history of tuberculosis
9. Allergy or contraindication to the used medications
10. Urethral stricture
11. Indwelling urethral catheter
12. Vesical stone.