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The Side Effects of Erectile Dysfunction Treatments


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Most men are able to use erectile dysfunction medication with no side effects, or only very minor ones. ED medication has been widely available since Viagra was first approved for medical use in 1998. The possible side effects of most medications have been widely studied and are well understood by doctors.

Millions of men around the world are currently taking ED medications safely and without serious adverse reactions. However, if you’re thinking about taking any prescription medicine, it’s important to familiarise yourself with all known side effects and to make an informed choice about the potential risks.

What causes side-effects?

Erectile dysfunction tablets use an active ingredient like sildenafil or tadalafil to inhibit the PDE-5 enzyme in your body, helping you to achieve firmer and longer lasting erections. This is partly possible because your blood vessels remain dilated, allowing a better blood supply to your penis.

Because all the blood vessels in your body are dilated, you may experience a temporary drop in blood pressure (hypotension). Men who suffer from low blood pressure may be unable to take ED tablets, or may have to use them under close medical supervision. Most of the common side effects of erectile dysfunction medication are due to their hypotensive effect.

Common Side Effects

If you’re taking ED medication, you may experience headaches and dizziness. These side effects can potentially occur with all brands of tablet, regardless of the active ingredient. 

Other common side-effects are hot flashes and a reddening of the face and upper body. Some men complain about a congested nose and nausea. In the vast majority of cases, these reactions are mild and only occur for a short time as the body adjusts to a slightly lower blood pressure.

If you experience any of these side effects, it may be worth experimenting with a different brand of tablet. If there are no prior health issues, your online GP may be able to prescribe you a trial pack of three different ED medications.


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There are some differences in side-effects and their frequency between the four PDE-5 inhibitors. Here’s a brief overview:


Sildenafil is the active ingredient in Viagra and the first medication to effectively treat erectile dysfunction. The iconic blue tablet has been on the market for over 20 years and is still the most popular and best-known ED medication. The fact that some patients experience minor side effects hasn’t reduced sildenafil’s popularity. 

In addition to the side effects mentioned above that are common to all ED medications, sildenafil can sometimes cause blurry vision. There is a long list of other potential adverse reactions, but these are considered to be exceptionally rare. Nonetheless, it is important to read the manufacturer’s pamphlet that comes with your tablets and be aware of any possible unwelcome side effects. 


The PDE-5 inhibiting substance in Cialis and its generic medicines is designed to remain active in the body for up to 36 hours. In addition to the minor side effects that can occur with all ED medications, tadalafil can cause muscle pains. About one in 100 men report pain in their arms, legs or back. Tadalafil can also occasionally cause acid regurgitation (reflux of stomach acid). Although tadalafil is generally very safe to use, you should read the product leaflet carefully before using any tadalafil based ED medication.

  • Vardenafil

Vardenafil is the active ingredient of the ED medication Levitra. Although vardenafil can cause headaches in patients, it is generally considered to have the mildest side effects of all ED medications. The frequency of reported unwelcome side effects is lower than other comparable medications and there are fewer possible side effects. These may include very occasional problems with your vision. A full list of potential adverse reactions is included in the product leaflet supplied with your medication. 

  • Avanafil

Spedra was approved by the EMA in 2013 and uses the PDE-5 inhibitor avanafil to treat erectile dysfunction. Although still a relatively new medication, avanafil is popular with users for its fast action and mild side effects. The common side effects include headaches, hot flushes, and nasal congestion, but these are only experienced by a minority of patients. Occasionally users may get a feeling of drowsiness or heavy tiredness. 

Everything you need to know about Erectile Dysfunction

Can PDE-5 inhibitors harm your health?

Erectile dysfunction medications use PDE-5 inhibitors as active ingredients. These substances can cause unwelcome side effects, but are generally very safe for the majority of healthy men. 

One of the ways in which PDE-5 inhibitors work results in temporarily reducing your blood pressure. They can be dangerous for men who already have low blood pressure, suffer from cardiovascular problems, or are taking conflicting medications like antihypertensive agents or blood thinners. 

Some men with these medical issues may still be able to use ED medication at low dosages and under close medical supervision.Your online GP will carefully consider your wider health profile and will only prescribe erectile dysfunction tablets if they are safe for you to use.  

When you complete the short online questionnaire, it is very important to be frank about any medical conditions that you suffer from. If your blood pressure drops too low, it can be life-threatening.

Misuse of ED medication and risks of overdose

Erectile dysfunction medications like Viagra, Levitra, Cialis and Spedra have been exhaustively tested and evaluated, initially in clinical trials and then by wider analysis of patient experience. The dosages have been set to offer optimal therapeutic benefits with minimal risks of unwelcome or dangerous side effects. You cannot enhance the effects of ED medications by taking larger doses or more tablets. Nor should you use ED tablets recreationally. 

Taking an extra dosage of erectile dysfunction tablets will not improve the quality of your erections, nor will it improve your sexual performance. It will expose you to the risk of unpleasant or even life threatening side effects. One possible consequence of misusing ED tablets is a medical condition called priapism. This is a permanent erection that remains even after you have had sex. If you experience a continual erection for more than two hours, you should seek immediate medical help. 

Choose your preferred medication and start your 2-minute online consultation now 

This article provides an overview of the most common side effects of erectile dysfunction treatments. Always consult a doctor if you are not sure whether a medication is suitable for you, or if you have unexpected side effects or symptoms. You can find the manufacturer’s leaflet of each medication on the related page of our website.It contains more detailed information about each medication and its individual side effects and contraindications.


Order your erectile dysfunction treatment

Viagra is one of the treatments prescribed by our doctors to treat erectile dysfunction. Learn more about our prices and how to order your treatment.

Read More

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