FAQs for specific tablets


What is erectile dysfunction (ED)?

Erectile dysfunction (impotence) is when a man has problems with getting an erection or maintaining an erection that is sufficient for satisfactory sexual intercourse. It is sometimes referred to as impotence.

Why me? Is ED a normal part of ageing?

No. The number of men affected increases with age, but it is not inevitable and it is treatable. ED/impotence is not uncommon. Around half of men aged 40-70 years experience some degree of ED, and this rises to 70% for over 70s.

For further information read Erection Changes After 50: The Facts.

I'm so embarrassed - do I really need to see my GP?

Yes. ED may be a result of treatable medical conditions. Your doctor may ask questions, examine you, and order a few simple blood tests to find out. It is important to identify and treat conditions such as cardiovascular disease, diabetes, or high blood pressure, as untreated your ED/impotence may worsen and also they may predispose to other serious conditions such as heart attacks and stroke. An online consultation does not replace a face-to-face assessment with a doctor.

See NHS - Erectile dysfunction (impotence) for further information.

How can I talk to my GP about this?

It is understandable for you to be embarrassed, but please be reassured that your doctor won't be. Your GP's role is to advise and help you. Your medical records are always confidential.

This is embarrassing, what can I say to my wife or partner?

Talking to your partner is very important. Acknowledge the issue. She may well be worried about it too. Reassure her that she is still attractive to you. If you can, tell her how you feel and ask her how she is feeling. You may be surprised how supportive she is.

What are the causes of ED?

ED (impotence) has physical and psychological causes, or can be due to a combination of both. The older you are the more common medical issues are. High blood pressure, diabetes, high cholesterol, hyperprolactinaemia, and obesity are all possible causes. They are treatable and if left undiagnosed or untreated pre-dispose to strokes and heart attack as well as causing ED. Less common causes are neurological diseases such as Parkinson's or multiple sclerosis, nerve or blood supply damage to the penis (as a result of injury of prostate, bladder, or rectal surgery).

Less commonly low levels of male hormone (testosterone) may affect a man's ability to get an erection. ED can also happen when a man's thyroid hormone level is too high or too low. ED can be a side effect of some medicines, including high blood pressure medication and antihistamines (medicines that treat allergies).

Cycling more than 3 hours a day can also cause ED.

What are the treatments for ED?

There are various treatment options. Firstly lifestyle adjustments would be advised. In some cases counselling is effective. The most common medicines prescribed are tablets called PDE5-inhibitors: sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra). These facilitate blood flow to the penis - this is the mechanism for getting and maintaining an erection. For most men these are very effective, but if not there are lesser used treatments such as urethral suppositories, injections, vacuum pumps, or surgery (penile implants).

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What can I do to improve ED without taking any medicines?

There are several lifestyle changes which can help ED/impotence. Stopping smoking, achieving a healthy weight, not drinking too much alcohol, or using recreational drugs, and having regular exercise.

Sometimes ED can have an emotional cause such as stress, depression or anxiety about sexual performance. In this case counselling can be effective.

Do tablets always work?

Tablets work in most men (around 75%). If the nerve supply to the penis is damaged, or if circulation is very poor, tablets may not work. Men with low testosterone levels may also be resistant to treatment. Testosterone levels should be checked before treatment, particularly in younger men (under 35 years). If one type of tablet does not work, it is worth trying a different one. Men who have a poor response to treatment or worsening ED should see their GPs. All men should consult a GP before starting treatment.

See also What to do if your ED medication isn't working

Does grapefruit cause issues with taking the tablets?

Grapefruit juice is a weak inhibitor of CYP3A4 gut wall metabolism and may give rise to modest increases in plasma levels of sildenafil.

Further information from NHS: Does grapefruit affect my medicine?

I have ED/impotence, is it forever?

That depends on the cause. Lifestyle changes and tackling stress can resolve the problem. Sometimes men get in a cycle of worry about sexual performance, which results in the very problem that is feared. Breaking that cycle with counselling or ED medications: sildenafil (Viagra), Tadalafil (Cialis), Vardenafil (Levitra) and Spedra (avanafil), is curative. It is important to have any medical causes treated. In most cases treatment for medical causes of ED, such as diabetes, and blood pressure is to prevent worsening of those conditions to reduce the risk of strokes and heart attacks. ED drugs sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) or avanafil (Spedra) are a treatment not a cure. They are used long term.

What are the risks of treatment and long-term side effects of Viagra?

Before a medication is licensed and available to prescribe, rigorous testing and clinical trials are performed. All new medications are monitored and any adverse events can be reported, by the prescriber or patient. In the UK this is via the MHRA (Medicines and Healthcare products Regulatory Agency) yellow card scheme.

In clinical trials Viagra was given to 3700 men, and over 550 were using it for over a year. The number of men stopping treatment due to side effects was 2.5%, which was not statistically different from placebo (2.3%).

In the past 15 years since Viagra became available, worldwide there have been millions of prescriptions. Serious adverse events are rare. In the low risk man (Viagra will not prescribed if patient is taking nitrates, has cardiac failure, or within half a year of a stroke or heart attack, and several other medical conditions, or when taking other medications that effect Viagra levels) adverse effects were mostly mild: headaches, flushing, heartburn, and nasal congestion.

The other ED/impotence medications, tadalafil (Cialis), vardenafil (Levitra) and avanafil (Spedra), went through equally strict clinical trials and although have lower usage figures than Viagra, work in a similar manner and are also very safe.

Is Viagra addictive?

No, the ED/impotence medicines aren't physically addictive. In a majority of cases ED drugs are treating symptoms rather than curing, so they will continue to be needed on an indefinite basis. If the underlying condition deteriorates, higher doses of medicine may be required.

When these medications are used for performance anxiety, men may become psychologically reliant on them: men feel unable to attempt sex without the backup. Rarely people are addicted to sex.

My partner has ED, is it me? What can I do?

Please be assured that ED has medical causes. It does not indicate that your partner no longer finds you attractive. Your partner may well be embarrassed and ashamed. Encouraging and supporting your partner to see his GP is important, to rule out treatable causes. Simple tablet treatments such as sildenafil (Viagra), Tadalafil (Cialis) and Vardenafil (Levitra) help a lot of couples re-attain their sex life.

I have ED, but we want to start a family, what can I do?

To start a family you need to have sex. Taking an ED/impotence medication: sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) or avanafil (Spedra) will improve your erectile function, enabling you to have intercourse. The more sex the greater the chances of conceiving. Studies show no adverse effects on sperm or testicular function with men using these medications.

When can you get NHS prescriptions for Viagra?

NHS prescribing restrictions for sildenafil (generic Viagra) have been relaxed, although treatment may be rationed (more information).

What is the difference between Viagra and the generic sildenafil? I see it's much cheaper, how come?

When a company makes a new drug it is patented. This gives the manufacturer exclusive rights to make that product for a set period of time. To make the drug commercially viable, the high cost of development and clinical trials needs to be recouped. Thus prices of new drugs reflects not only the production cost but also all the pre-manufacture costs too.

Once the patent runs out (Viagra's patent expired June 2013) then any company can make the product. As there are no research, trial and marketing costs, and there is competition, the prices are significantly lower. These generic versions contain the same active ingredients as the original. They are considered the same, but some men do notice variations in effect and side effects.

I have a private prescription for Viagra - can I get cheaper generic sildenafil?

No, if a brand name is prescribed, then that brand rather than a generic equivalent must be dispensed. If you prefer generic sildenafil, you need to request it at the time the prescription is written.

Branded Viagra and generic sildenafil can both be requested through an online consultation.

I have heard I can split pills to save money?

This is not recommended by the manufacturer, but it is commonly done. Pill cutters are available to buy. Some pill manufacturers score their pills to allow them to be more easily broken into 2 or 4. Capsules must not be divided.

Is it safe to buy erectile dysfunction medicines online?

In the UK, the legal and regulatory framework is in place to permit prescribing of ED medicines online. The NHS advice is to make sure any online doctor service is registered with the Care Quality Commission.

Before ordering medicines online at Dr Fox men must first read medical information about erectile dysfunction and answer medical questions to check for eligibility. Our doctors will then review your information before prescribing, and are available to answer any questions you may have. Medicine is posted direct.

Studies suggest that men are capable of using written patient education materials to accurately assess their suitability for treatment.

Most men do not seek medical help for their erectile dysfunction. Embarrassment or social stigma may lead some men to self-treat by ordering online.

Can I use erectile dysfunction medication for many years?

There has actually been no research on very long term use of erectile dysfunction (ED) medication. A study from 2003 of 1173 men using tadalafil for 18 months to 2 years showed no problems. A study from 2007 looked at 4 years of sildenafil use and there were no concerns. Tadalafil is often used for other medical conditions such as benign prostatic hyperplasia, and is often used in these circumstances for long periods of time with no problems reported. Therefore, ED medications are generally believed by doctors to be safe to use long term.

You should from time to time try without, to see if you still need the help of ED medication, although ED medication does not actually cure any underlying condition affecting erection. There is no evidence that you can become physically dependent on ED medication, but some men could develop a psychological dependence. ED will also usually get worse as you get older, and you may find lower dose tablets become less effective.

Does having erectile dysfunction mean there's something seriously wrong with my health?

In older men, erectile dysfunction can be an early sign of hardening of the arteries which can eventually lead to heart disease, strokes, and damaged circulation. If you are over 45 it is important that your GP is aware of your problem.

Are there any natural alternatives to ED medication?

Ginseng, rhodiola rosea, yohimbe, ginkgo biloba, saw palmetto, and others have all been suggested to help with ED. However natural products are generally unregulated and difficult to evaluate, with no large-scale medically supervised trials. Dr Fox only supplies prescription drugs that have been assessed and authorised by the MHRA regulation.

See Natural Viagra alternatives for further information.

I have had a stroke - how long should I wait before using ED medication again?

It is advised to wait for three months. See Sex and intimate relationships after stroke.

Is tadalafil/sildenafil used for other medical problems as well as ED?

Tadalafil and sildenafil are both licensed to treat some other medical conditions as well as erectile dysfunction.

  • They can both be used for a rare condition causing high blood pressure in the lungs (pulmonary hypertension).
  • Tadalafil is also prescribed by specialists to relax the prostate, if an enlarged prostate is causing urination problems, and sometimes after prostate surgery.
  • Sildenafil can also be prescribed by specialists to help treat finger ulcers caused by the rare condition systemic sclerosis.

Dr Fox only prescribes tadalafil and sildenafil for ED problems. Any other use requires supervision and monitoring from a specialist.

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Dr Tony Steele

Authored 22 October 2013 by Dr Tony Steele
MB ChB Sheffield University 1983. Former hospital doctor and GP.

Reviewed by Dr A. Wood, Dr B. Babor, Dr P. Hunt
Last reviewed 12 May 2021
Last updated 14 July 2021