Man sleeping with blue tablets on his bedside cabinet, erectile dysfunction | e-Surgery

The hard truth about erectile dysfunction drugs

As a pharmacist, my biggest pet peeve is hearing myths about certain drugs. One of the most common revolves around ED tablets giving you a raging boner that lasts for hours (which is actually a condition called Priapism and can be very dangerous). If you didn’t already know this, let me just say: it doesn’t work that way. Around half of the men in the UK between the ages of 40 and 70 reported problems with erection and millions have used or considered using erectile dysfunction medication such as Viagra, Cialis, Spedra, or Levitra. So for those curious, let’s dispel some myths and shed some light on these erectile dysfunction treatments, shall we?

Do ED tablets actually work?

The treatment of erectile dysfunction has come a long way in the past few years. This is good news for erectile dysfunction sufferers. Before the introduction of ED tablets, treatments like penis pumps, creams, and injections (yes directly into the penis) were considered the norm. In double-blind trials (accounting for the placebo effect) PDE5 inhibitors had on average a success rate of 65-70% in treating erectile dysfunction [1]. Compare this to around 20% efficacy of SSRIs (the most common antidepressants prescribed every day in the UK )[2] and it’s clear that current ED treatments on the market are very effective.

How do ED tablets work?

As the name suggests PDE5 inhibitors inhibit the PDE5 enzyme that breaks down a molecule involved in increasing blood flow called cGMP. I could get very technical here but all that is really important is that PDE5 inhibitors increase blood flow to the penis in response to sexual arousal. PDE5 inhibition = more cGMP = harder and longer erections. Again, this cycle is only triggered when one is physically turned on.

Are ED tablets safe?

All drugs have the potential to be dangerous. Take aspirin tablets on an empty stomach and the cramps and possible ulcers will soon make you regret it. Erectile dysfunction treatments as a family are quite well tolerated [3] when taken as prescribed. Due to the ’embarrassing’ nature of the condition (despite how common it is) many will turn to the internet for advice. When ordering ED treatment online it’s important to buy from reputable, registered online pharmacies and AVOID fake, unlicensed, or counterfeit treatments. Vidalista and Sildamax are just some examples of treatments to avoid.

Are There Side Effects of ED tablets?

Of course, there are. Like with all drugs there are always potential side effects. However, for PDE5 inhibitors these are usually mild such as a headache, nasal congestion, and bloodshot eyes. This is due to vasodilation occurring in other parts of the body (other than your penis that is). One side effect to be aware of however is priapism, which is an erection lasting longer than 4 hours. Now don’t get too excited, this is a real emergency and usually involves ice packs and sometimes even needles to fix (I’ll leave that to your imagination). Luckily it is very rare.

The star ED tablet lineup

Viagra (Sildenafil)

Viagra is the original PDE5 inhibitor and a name that everyone recognizes and the undisputed king in its class. It is the Connor McGregor of erectile dysfunction. The real name of the active drug, however, is Sildenafil and originally designed for pulmonary arterial hypertension. That’s a fancy term for increased blood pressure inside the lungs, quite a rare condition. However, during clinical trials of Viagra, the researchers noted a peculiar side effect. Or perhaps it was the partners of the trial subjects?

Either way, the marketing department at the company got word of this and the rest is history. Viagra Connect has recently been made available in the 50mg strength as a pharmacy medication in the UK. This means that you can buy it after a consultation with a pharmacist. This is a pricey option, however, at a retail price of £19.99 for 4 tablets and £34.99 for 8. Luckily since Viagra has come off patent, generic versions are available under a private prescription. These are available in 25mg, 50mg, as well as 100mg strengths. I recommend going for the generic option as it will save a ton of money in the long run as well as being available in the strongest 100mg version.

Cialis (Tadalafil)

Nicknamed “The Weekender” Cialis is sold by Lilly. The actual drug name is Tadalafil (see a trend here with the -afil?) and its main advantage is the much longer duration of action. It is claimed to last between 24 and 36hrs. Its onset of action is also reported to be quicker than Sildenafil. Tadalafil also shows the highest statistical success rate of any drugs in this class and on paper is a clear winner. While the Cialis brand tends to be the most expensive, cheaper generics are available for Tadalafil and come in 2.5mg, 5mg, 10mg, and 20mg strengths. Tadalafil is available in a daily version.

Levitra (Vardenafil)

Produced by Bayer, Levitra is another PDE5 inhibitor drug. Vardenafil’s duration of action is slightly longer than sildenafil. These come in 10mg and 20mg standard as well as orodispersable tablets.

Spedra (Avanafil)

Promoted by the Spanish company Menarini, Avanafil is the real drug name of Spedra. The main advantage of this drug is the onset of action. It takes as little as 15min to notice an effect. Avanafil comes in 50mg, 100mg, and 200mg strengths.

Just in case you weren’t paying attention this handy chart helps you decide which medication is right for you by comparing Sildenafil (Viagra), Tadalafil (Cialis), Vardenafil (Levitra) and Avanafil (Spedra):

Chart comparing different ED medications


Go for generic ED tablets

Boxes of Sildenafil and Tadalafil in varied strengths.

Due to the NHS restrictions on erectile dysfunction drug prescribing, the majority of men in the UK find themselves getting these drugs on a private prescription. However, this means paying for the cost of the drugs themselves. The prices of branded products such as Viagra and Cialis can be very high, however. This is where generic versions come in, currently available for Sildenafil and Tadalafil Tablets. Because of increased competition amongst suppliers, these drugs are significantly cheaper than their branded counterparts and by law have to contain the exact same active ingredients and strengths.

If you are getting them online make sure you are obtaining them from a regulated doctor service that dispenses genuine UK medicines such as Always look for the green MHRA logo to make sure the service is safe and legal.


  1. Phosphodiesterase type 5 inhibitors as a treatment for erectile dysfunction: Current information and new horizons
  2. Depression: How effective are antidepressants?
  3. Comparative effectiveness and safety of oral phosphodiesterase type 5 inhibitors for erectile dysfunction: a systematic review and network meta-analysis.
  4. Comparison of PDE5 Inhibitors

Further Reading

  1. Erectile Dysfunction (impotence) | NHS
  2. Sildenafil | National Institute For Health And Care Excellence
  3. Tadalafil For Erectile Dysfunction | PatientInfo
  4. Vardenafil HCL Tablet | WebMD
  5. Avanafil: Uses, Side Effects & Warnings |