ED drugs

FAQs on the drugs used to treat erectile dysfunction (ED) or impotence.
What drugs are there for erectile dysfunction?

A class of drugs called Phosphodiesterase-5 (PDE-5) inhibitors is widely used and effective. They increase the blood flow to your penis temporarily.

The four most common in England are:
    •    sildenafil – brand name Viagra 
    •    tadalafil – brand name Cialis
    •    vardenafil – brand name Levitra
    •    avanafil – brand name Spedra

Viagra came off patent in the UK in 2014 and the others are following. This means companies can now manufacture cheaper ‘generic’ versions of the drug. 

How should you take them?

Sildenafil and vardenafil take about an hour to get going and then last for 8-9 hours. Avanafil kicks in sooner. Tadalafil lasts longer – up to 36 hours.

Take PDE-5s on an empty stomach (you can eat an hour later) and only take one tablet within a 24-hour period.

These treatments are helpful for most men with ED (between two-thirds and three-quarters) but they’re not instant erection pills. You still need regular sexual stimulation. In other words, you still need to be turned on.

If they don’t work for you, make sure you’re not trying to soon (before the drug has kicked in) or too late (after it has died down) but don’t mess about with the dose without talking to your GP. The NHS reckon that at least two-thirds of men report having improved erections after taking PDE-5s.

Who shouldn’t take them?

Be careful if you have heart problems. Yes, sex is good for your cardio health but PDE-5s can be dangerous if you have a heart condition, are taking blood pressure medication such as alpha-blockers or have had a heart attack or stroke so discuss with your GP. (Erection problems can also be an early sign of heart disease so you should see your GP about erection problems anyway so heart disease can be checked out as a possible cause.)

Also talk to your GP if you have Peyronie’s disease, priapism or are taking drugs that contain nitrates, whether prescribed (eg. for angina) or recreational (eg. poppers).

Any side-effects?

Yes. PDE-5 inhibitor side effects include:

  •     headaches and migraines
  •     flushing (redness) 
  •     indigestion
  •     nausea (feeling sick)
  •     vomiting (being sick)
  •     blocked or runny nose
  •     back pain
  •     vision disturbances
  •     muscle pain
Can I get ED drugs on the NHS?

NHS prescriptions for other PDE-5 inhibitors will depend on your particular circumstances. In some cases, you may need to pay.

You should get PDE-5s prescribed if you have diabetes, multiple sclerosis, Parkinson’s disease, polio, prostate cancer, spina bifida, certain genetic conditions (such as Huntington's disease) or are receiving or have received certain other medical treatments (eg. pelvic surgery, prostate treatments or kidney treatments including dialysis and transplant).

You can buy Viagra Connect at a pharmacy or online. You'll need to have a discussion with the pharmacist to check that you can take the drug safely and to rule out more serious causes of ED. 

Do not buy these drugs online without a prescription except through a recognised pharmacist. You can check if a vendor is authorised on the MHRA website. (See the internet and health for more information.)


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MAIN IMAGE: Erection by jm3 licensed under CC BY-SA 2.0

Date published 08/03/16
Date of last review 20/01/21
Date of next review 19/01/24


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