From the Guidelines
Increasing tamsulosin from the standard 0.4 mg to 0.8 mg dose is unlikely to significantly help with overactive bladder (OAB) symptoms in males. Tamsulosin is primarily effective for benign prostatic hyperplasia (BPH) symptoms like weak stream and hesitancy, as it relaxes smooth muscle in the prostate and bladder neck 1. However, it has limited effect on OAB symptoms such as urgency, frequency, and nocturia. For OAB in males, anticholinergic medications (like oxybutynin, solifenacin, or tolterodine) or beta-3 agonists (like mirabegron) would be more appropriate treatments as they target the bladder muscle overactivity that causes OAB symptoms 1. Some key points to consider when treating OAB in males with BPH include:
- Clinicians should offer patients with BPH and OAB monotherapy with antimuscarinic medications or beta-3 agonists, or combination therapy with an alpha blocker and an antimuscarinic medication or beta-3 agonist 1.
- Antimuscarinics and beta-3 agonists are effective in treating OAB in this population as monotherapy 1.
- If a patient is already on tamsulosin for BPH but experiencing persistent OAB symptoms, adding one of these bladder-specific medications would likely be more effective than increasing the tamsulosin dose.
- Side effects of higher tamsulosin doses include increased risk of orthostatic hypotension, dizziness, and ejaculatory dysfunction without providing significant additional benefit for OAB symptoms 1.
From the Research
Tamsulosin Dosage and Overactive Bladder (OAB) in Males
- Increasing tamsulosin to 0.8 mg may help with OAB in males, as studies have shown that tamsulosin 0.4 and 0.8 mg/day can improve lower urinary tract symptoms (LUTS) and maximum urine flow (Qmax) in patients with benign prostatic hyperplasia (BPH) 2, 3.
- A study found that tamsulosin 0.4 mg once daily was effective in improving LUTS and Qmax, and that increasing the dose to 0.8 mg may provide additional benefits 4.
- However, another study found that the improvement in International Prostate Symptom Score was not different between the 0.2 mg and 0.4 mg groups, but the improvement in maximum flow rate was greater in the 0.4 mg group 4.
- It's worth noting that the combination of tamsulosin and mirabegron has been shown to be effective in treating OAB symptoms in men with BPH 5, 6.
Efficacy and Safety of Tamsulosin
- Tamsulosin has been shown to be effective in improving LUTS and Qmax in patients with BPH, with a rapid onset of action and a low potential for hypotensive effects or interference with concomitant antihypertensive therapy 2, 3.
- The most common adverse events associated with tamsulosin are dizziness, abnormal ejaculation, and asthenia, with a low incidence of postural hypotension and palpitations 2, 3.
- Increasing the dose of tamsulosin to 0.8 mg may be safe and effective in patients who do not respond to lower doses, without increasing the risk of cardiovascular complications 4.
Combination Therapy with Mirabegron
- The combination of tamsulosin and mirabegron has been shown to be effective in treating OAB symptoms in men with BPH, with a low occurrence of side effects 5, 6.
- Mirabegron has been shown to improve OAB symptoms, including the mean number of micturitions per day, urgency episodes per day, and total OAB symptom score, in men receiving tamsulosin therapy 6.
- However, the administration of mirabegron may have the risk of increasing post-void residual urine volume, and should be monitored accordingly 6.