Problems of a large prostate

Benign prostate hyperplasia (BPH) is a common condition seen in middle-aged and elderly men. It is an enlargement of the prostate gland, which - although not cancerous - may cause problems, as it may impede the flow of urine out of the bladder.

It may also cause bleeding during urination, and predispose to infection of the urine.

If urine is totally obstructed from passing out of the bladder, it will cause a build-up of pressure and urine in the bladder, which when severe, may cause back-pressure, as well as reflux of urine into the kidney. This will eventually cause renal failure.

BPH and sex

Aside from all the problems described above, BPH may also affect a man's sexual life.

Multiple studies have shown that BPH and sexual dysfunction are inter-related.

Sexual dysfunction refers to sexual problems, such as erectile dysfunction (unable to maintain satisfactory erection of the penis for sexual intercourse), ejaculatory dysfunction (failure to expel semen), and low sexual desire.

BPH has been found to be a risk factor for erectile dysfunction, independent of age.

BPH has also been found to be a stronger predictor of sexual dysfunction compared to diabetes, heart disease or hypertension. In fact, erectile function has been shown to deteriorate in tandem with worsening symptoms of BPH.

How does BPH cause worsening of sexual function?

There are a few theories, which include the nitric oxide/cyclic guanosine monophosphate pathway, rhokinase, overactivity of the autonomic pathway, and pelvic organ atherosclerosis.

All these theories have one thing in common - failure of relaxation of the smooth muscle.

Relaxation of the smooth muscle in the erectile tissue of the penis is needed for engorgement of the penis with blood.

Similarly, relaxation of the smooth muscle in the prostate and bladder neck is needed for urine to pass out of the bladder through the penis.

When there is failure of relaxation of the smooth muscle in the penis, this leads to erection difficulties; while in the prostate and bladder neck, urination difficulties occur.


Treating BPH

Treatment of BPH consists of medical, as well as surgical interventions.

So, does treating BPH improve the symptoms of BPH?

It depends on the medication given. There are basically two groups of medication for BPH, ie alpha blockers and the 5α reductase inhibitors.

Examples of alpha blockers include terazosin, doxazosin, alfuzosin, tamsulosin and silodosin.

There are only two types of 5α reductase inhibitor in the market, ie finasteride and dutasteride.

Alpha blockers have been shown to improve erectile function. Those with worse erectile function had better improvement with alpha blockers.

However, not all the alpha blocker drugs have similar effects on ejaculation. Alpha blockers that act more specifically on the prostate (uroselective), like silodosin, have been shown to have detrimental effects on ejaculation. There is no effect on sexual desire.

The 5α reductase inhibitors act by inhibiting the conversion of testosterone to dihydrotestosterone.

Dihydrotestosterone is the potent hormone that causes growth of the prostate. It is also commonly known as the male hormone responsible for male characteristics.

Therefore, it is no surprise that 5α reductase inhibitors are associated with a decrease in sexual desire and erectile dysfunction. It is also detrimental to ejaculatory function as well.

However, these sexual dysfunctions are seen mainly during the first year of treatment. The incidence of these problems decreases with longer duration of therapy.

Sometimes, both the alpha blockers and 5α reductase inhibitors are used in combination to treat BPH.

Although symptoms of BPH show better improvement with combination therapy, the incidence of sexual dysfunction increases as well. In fact, the incidence of sexual dysfunction is much worse compared to using either medication alone.

What about surgical treatment?

The gold standard for treatment of BPH is still transurethral resection of the prostate (TURP).

The evidence for sexual dysfunction after TURP is debatable. There are studies which show that it worsens sexual function, but conversely, there are also other studies that show otherwise.

However, what is consistent is the evidence that minimally-invasive treatment of BPH like transurethral microwave therapy (TUMT) and transurethral needle ablation (TUNA), is less detrimental to sexual function compared to TURP.

Unfortunately, the long-term success rate for treatment of BPH symptoms with these minimally-invasive therapies are not well established, and may be lower than TURP.

Restoring sexual ability

Restoring sexual ability

All is not lost if sexual dysfunction occurs as a result of BPH or its treatment.

If erectile dysfunction occurs, phosphodiestaerase-5 inhibitor medications like vardenafil, tadalafil and sildenafil, can be used.

However, there is a higher risk of postural hypotension (drop in blood pressure) when it is taken together with alpha blockers.

In this situation, the alpha blocker used should be a more uroselective drug (like tamsulosin), which has less complications of hypotension.

Other treatments include intracavernosal prostaglandin injections (injecting a medication known as prostaglandin into the penis), vacuum pump devices, as well as penile prostheses (implanting a medical device into the penis).

If ejaculation is a problem, the alpha blocker can be switched to one that has been proven to have less ejaculatory side effects (like alfuzosin).

There are also other modalities of treatment. However, all these problems are best managed by urologists.

BPH may cause sex-related problems. Similarly, its treatment may also cause sexual dysfunction.

There are treatments available to help alleviate these sexual problems. Consultation with a urologist would be the best step to take.


1. Braun MH, Sommer F, Haupt G, Mathers MJ, Reifenrath B, Engelmann UH. Lower urinary tract symptoms and erectile dysfunction: co-morbidity or typical 'Aging Male' symptoms? Results of the 'Cologne Male Survey'. Eur Urol 2003; 44: 588-94.

2. Rosen R, Altwein J, Boyle P et al. Lower urinary tract symptoms and male sexual dysfunction: the Multinational Survey of the Aging Male (MSAM-7). Eur Urol 2003; 44: 637-49.

3. Mirone V, Sessa A, Giuliano F, Berges R, Kirby M, Moncada I. Current benign prostatic hyperplasia treatment: impact on sexual function and management of related sexual adverse events. Int J Clin Pract. 2011;65(9):1005-13

4. AUA Practice Guidelines Committee. AUA guideline on management of benign prostatic hyperplasia (2003). Chapter 1: Diagnosis and treatment recommendations. J Urol 2003;170:530-47.

5. Mebust WK, Holtgrewe HL, Cockett AT, Peters PC. Transurethral prostatectomy: immediate and postoperative complications. A cooperative study of 13 participating institutions evaluating 3,885 patients. J Urol 2002; 167: 999-1003

6. Jadaine M et al. Effect of TURP on Erectile Function: A Prospective Comparative Study. Int J Impot Res 2010; 22: 146-51

7. Mishriki SF et al. TURP and sex: patient and partner prospective 12 years follow up study. BJU Int 2011; 109: 745-50

8. Hoffman RM, Monga M, Elliot SP, Macdonald R, Wilt TJ. Microwave thermotherapy for benign prostatic hyperplasia. Cochrane Database Syst Rev 2007; CD004135

9. Bouza C, López T, Magro A, Navalpotro L, Amate JM. Systematic review and meta-analysis of transurethral needle ablation in symptomatic benign prostatic hyperplasia. BMC Urol 2006; 6: 14

This article is contributed by The Star Health & Ageing Panel, which comprises a group of panellists who are not just opinion leaders in their respective fields of medical expertise, but have wide experience in medical health education for the public.