Erectile dysfunction

Also known as impotence

Erectile dysfunction means a man is unable to maintain an erect penis sufficient for satisfactory sexual intercourse. Many men have erection problems at times, and the likelihood increases with age.

Erectile dysfunction may have a psychological or a physical cause, either way, it is distressing and may cause loss of confidence and self-esteem or depression, as well as relationship problems. There are several solutions, but recognising the problem and talking about it with your doctor are the first essential steps.

What causes erectile dysfunction?

How does an erection happen?

The veins that allow blood to leave the penis are only so wide. During an erection, the blood vessels that let blood into the penis relax and widen (dilate). This lets more blood in – more than can escape – which causes the sponge-like tissues of the penis to swell and harden.

Complex biological mechanisms are involved in allowing these blood vessels to relax and redirect blood to the penis. Your thoughts and senses (touch, hearing, smell and sight) influence a part of the brain that can trigger an erection.

In addition, hormones and other substances determine how your nerves transmit ‘sexual signals’ and how blood vessels respond to the received signals. Arousing thoughts or nervous mechanisms (eg, touch reflexes) are two ways an erection is initiated.

What causes an erection to fail?

Erectile dysfunction occurs when sexual stimulation or arousal (you may still ‘have the urge’) does not result in sufficient blood flow to the penis. For most men there is a physical or medical reason for this, for others the problem is related to thoughts or emotions.

Even when there is an initial physical reason, a man may still feel anxious about having sex, and this can compound the problem.

Physical & medical reasons

Recent illness, such as a heart attack, or injury to the brain or spinal cord, can be a cause. Many other medical conditions can also lead to nerve damage or reduced blood supply to the penis – the most common of these is diabetes (men with diabetes are much more likely to have problems with erections).

Other factors that can reduce blood flow to the penis include:

  • excess alcohol
  • smoking
  • use of social drugs such as marijuana, cocaine
  • narrowing of blood vessels caused by a high blood cholesterol level
  • medications - wide range such as in Table 1.  Any concerns, discuss with your doctor for possible alternatives.

Medicines that can cause erectile dysfunction¹

Medication class  Examples Possible alternative with lower risk of erectile dysfunction
Antihypertensives Beta blockers, calcium channel blockers ACE inhibitors
Diuretics Thiazides, spironolactone Loop diuretics
Antidepressants Selective serotonin reuptake inhibitors, tricyclic antidepressants, monoamine oxidase inhibitors Limited evidence to guide alternative; specialist review required for any change
Antipsychotics Phenothiazines, carbamazepine, risperidone Limited evidence to guide alternative; specialist review required for any change
Hormones Cyproterone acetate, oestrogen, 5α-reductase inhibitors (e.g. finasteride) Limited evidence to guide alternative; specialist review required for any change
Dyspepsia and ulcer healing drugs H2 antagonists Proton pump inhibitors
Recreational drugs Alcohol, marijuana, cocaine Discontinue use

Psychological reasons

There are a range of psychological factors including:

  • existing values or attitudes towards sex
  • stress, guilt, depression or fatigue
  • anxiety about your performance during sex
  • relationship problems (possible anger, power or control issues with your partner)
  • problems with intimacy and communication.

If you still have erections at times (eg, when you wake) this usually means psychological reasons are involved.

What are the symptoms of erectile dysfunction?

Some estimates indicate that about 40% of men over the age of 40 will have erection problems at times. Symptoms of erection problems include:

  • being unable to get an erection
  • experiencing a partial erection
  • having an erection of a shorter than usual duration.

How is erectile dysfunction diagnosed

Many men are unhappy with their ability to get or maintain an erection, but only 5% of these men seek help. This is because most men, in general, are unwilling to discuss their sex life, even when it is going well.

Understanding that erectile dysfunction could have a medical cause, just as asthma or arthritis do, can allow you to feel more at ease in mentioning it to your doctor. By opening up this discussion, which is confidential, your doctor can help you in a number of ways.

Your doctor can check your health and any current medications for likely side effects. If psychological reasons are suspected, your doctor can advise you on the appropriate action and help you access counselling services you (and your partner) may benefit from.

Tests by your doctor may include:

  • A physical examination, which may include the genitals and prostate gland.
  • Checking your medications for side effects.
  • Blood and urine tests for hormones, blood lipids, liver and kidney function and diabetes.

If your erection problems have a medical cause, your doctor can explain the treatment options, the techniques needed to make them work and their suitability for your needs in the light of your overall health.

How is erectile dysfunction treated?

The available treatments for erectile dysfunction are summarised below. Your doctor can advise you on the benefits and drawbacks of each. 

  • psychological counselling (whether or not there is a medical cause)
  • oral tablets
  • self-injection or penile insertion of a drug
  • vacuum pump devices
  • rigid or inflatable surgical penile implants
  • testosterone replacement (only for men with low levels of this hormone).

Oral medications

The drugs sildenafil, tadalafil and vardenafil (also called PDE5 inhibitors) ‘prime’ the penis by allowing the blood vessels to relax, while another drug apomorphine acts by enhancing the brain’s response during arousal.

  • The PDE5 inhibitor type of tablets (with brand names such as Viagra®, Avigra®, Silvasta®, Cialis®, Levitra®) usually allow an erection to occur, but only when the man is stimulated or aroused.
  • They work well for most men with erectile dysfunction, allowing intercourse (or sex) in about 70% (7 out of every 10) users, but may work as well for men with diabetes and who have had prostate surgery, or severe erectile dysfunction.
  • They can cause headaches, dizziness and nausea. PDE5 inhibitors can cause flushing or rarely some visual disturbance. Men with certain heart conditions or those taking nitrates for angina cannot use PDE5 inhibitors as this combination has proved fatal in some circumstances.

Talk to your doctor about which treatment is right for you as this will depend on the possible causes. If there are no health concerns, you can buy sildenafil directly from some pharmacies after a consultation with the pharmacist or see a doctor for a prescription. 


If the tablets mentioned above don't work, then injecting a prostaglandin drug into the base of the penis is another option. It allows most men to get an erection, which may last beyond ejaculation. Some men may be put off by this method, but the injector devices are simple and convenient to use and the procedure is virtually painless.¹

Do herbal products work?

Many herbal products such as Horny goat weed, ginkgo, yohimbe and ginseng claim to improve sexual function. There is no sound evidence that these herbal products work well for erectile dysfunction. They have not been well-studied or tested. Since some erectile dysfunction is related to psychological problems, herbal products may help with anxiety, which may indirectly help sexual function. Some herbal products and supplements can cause side effects or interact with other medicines. Talk to your doctor or pharmacist before you try an alternative treatment for erectile dysfunction — especially if you're taking medications or you have a chronic health problem such as heart disease or diabetes.³        

Self care for erectile dysfunction

Most ageing men manage to get erections, but to do so requires more stimulation. It is up to each man to decide whether his erection is adequate. You can consider (with your partner) how important sexual intercourse is to your relationship – there are other aspects to intimacy, and not all couples require an active sex life to have a fulfilling relationship.

You can help yourself by cutting down on alcoholstopping smoking and reducing the stress in your life.


  1. Erectile dysfunction Best Practice Journal, April 2008
  2. Erectile Problems Best Health (UK), 2014
  3. Dietary supplements for erectile dysfunction: A natural treatment for ED?  Mayo Clinic (US), 2017 
Credits: Health Navigator Editorial Team.