Erectile Dysfunction

Key points:


  • ED is age-related but can also be caused by physical and psychological disorders
  • Hormonal causes, especially testosterone deficiency, need to be excluded
  • ED is treatable with drugs that increase the blood flow to the penis (Viagra, Levitra, Cialis)


Erectile dysfunction (ED) is the inability to attain or maintain erection sufficient for satisfactory sexual intercourse. The causes of ED are advancing age, hypertension, diabetes mellitus, neurological diseases, pelvic surgery / injury (from prostate cancer surgery or radiation), and medications. The basic process of erection requires blood to enter the penis and remain in the penis until the act of intercourse is completed. This requires patent arteries, intact nerves, normal testosterone levels, and libido. Hence, any disease that affects the blood vessels, nerves, (esp. diabetes, hypertension, drugs) hormone levels (esp. aging) and mental health (esp. stress, depression, alcohol, drugs) can cause ED. Because of this strong association, ED can also be a harbinger of neurovascular diseases and should not be viewed as a disease in isolation. Indeed, many men have subsequently been found to have significant heart disease and early diabetes upon further evaluation.


A questionnaire is available to help patients and doctors determine the severity of the ED. This is the IIEF-5 questionnaire and a score of 21 or less indicates significant ED. [Fig 1] There are also scans that can be done, eg. doppler ultrasound but is reserved for those who do not respond to treatment, and in whom surgery is contemplated.

Fig 1. The IIEF-5 questionnaire



The treatment of ED falls into 4 groups:

  1. Psychotherapy – this is for those who have stress, anxiety or depression affecting their erection.
  2. Drugs [Fig 2] – oral medication like PDE5 inhibitors are established and safe so long as the patient has no unstable heart disease and is not on nitrate medication. These drugs are > 90% effective
  3. Penile injection of vasoactive drugs [Fig 3] – the most common is prostaglandin (PGE1) which is safe and lasts for an hour. However, the injection itself causes a burning pain.
  4. Devices [Fig 4] – a vacuum pump sucks out blood into the penis with a ring placed around the base of the penis to prevent the blood from draining out
  5. Surgery [Fig 5] – involves tying up veins or inserting in an implant to create an artificial erection.
Fig 2. The 3 available PDE5 inhibitor drugs
Fig 3. PGE1 injection into the penis
Fig 4. Vacuum pump device

The vacuum pump (Fig 4) is rather cumbersome to use because it requires the placement of a rubber ring (c) at the base of the penis and using a hand-held pump (b) to create a vacuum within the cylinder (a) to draw blood into the penis.

Venous leak ligation surgery does not have sustainable results while penile implant surgery is expensive and has risks of infection and implant failure.

Fig 5. Penile implant

Despite the initial fears and reports of sudden deaths, all the PDE5 inhibitor drugs are safe provided the genuine drug is taken. There are a lot of fake ones in the market and the danger is that they may be laced with dangerous chemicals. The side effects of headache, flushing and nasal congestion usually diminish with subsequent doses. The recent reports of sudden blindness are rare occurrences and seen mostly in those with long-standing hypertension and diabetes. Natural remedies from ginseng to tongkat ali are but plants extracts that have even been made into pills. There are no studies that show they are superior.