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Are Side Effects Cause for Concern When Taking ED Tablets?

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Whatever is true for other prescription medications counts for ED pills as well: Follow the instructions, and you shouldn't have anything to worry about. However, the majority of users simply skim through the leaflet to see when to take it if they have a romantic date scheduled at 10 PM.

We want to give you an overview of what to expect, why some physical reactions are completely normal, and when you need to be careful with the medication.

What causes side-effects?

Let’s take a quick look at what happens in the body and during an erection. With sexual stimulation, increased nitric oxide release causes increased production of the enzyme cGMP. This dilates the blood vessels, allowing more blood to flow into the penis. The active ingredient in an ED medication supports this enzyme. More importantly, though, it inhibits the PDE-5 enzyme, which breaks down cGMP, thus causing an erection to subside. Hence the name PDE-5 inhibitor.

PDE-5 inhibitors work in the entire body, not just in the penis. In other words, the expansion of blood vessels occurs elsewhere in the body as well, leading to various reactions. The blood pressure drops slightly and the user can experience an increased blood flow in certain body parts. This is not uncommon, and usually no action is required.

When the head spins and the nose gets stuffy

PDE-5 inhibitors, the active ingredients in Erectile Dysfunction treatments have a hypotensive effect, which is the main reason for most side effects. Headaches and dizziness are common in all ED pills. Other shared side-effects are hot flashes and reddening of the face and upper body. Men complain about a stuffy nose and nausea. In the vast majority of cases, these reactions are mild and occur for a short time, until the body gets used to the slightly lower blood pressure.

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


The active ingredient in Viagra and pioneer among the medications targeting erectile dysfunction. The blue tablet has been on the market for over 20 years already and is still the most popular. The fact, that it can cause a rather large variety of side effects does not interfere with its fame.

More than 10% of users experience headaches after taking the medication. In addition to the reactions mentioned above, Sildenafil can sometimes cause blurry vision. The list of other occasional and rare side effects is long. Seldom are they dangerous or have a lasting effect. Be sure to read the side-effects section in the package insert.


The PDE-5 inhibiting substance in Cialis and its generic medicines has the advantage of remaining active in the body for a long time. In addition to the side-effects as mentioned above, Tadalafil can cause muscle pains. About one out of 100 men report pain in arms, legs or back. Also unique to this medicine is the occurrence of Acid regurgitation (reflux of stomach acid). Carefully read the product leaflet before using the medicine.


Today the only medication with Vardenafil as the active ingredient is Levitra. Although headaches are rather frequent when taking Levitra, it is considered the most compatible of all ED medications. This is because the frequency in which other side effects are reported is lower than in other medicines and the variety is smaller. Only occasionally is the eyesight impaired, hot flashes are not familiar to Levitra users. Find out more in the patient information leaflet.


Spedra uses the fourth and “youngest” known PDE-5 inhibitor. Avanafil is another gentle substance when it comes to physical reactions. Headaches, hot flashes, and nasal congestion are the only side effects that are reported frequently. Occasionally a man may get a feeling of drowsiness or heavy tiredness. Since this medication has only been around for a few years, there are less reports from user experiences. Please make yourself familiar with the information from the leaflet.

When can PDE-5 inhibitors be harmful to health?

Again, side effects are usually mild and pass quickly. They will not prevent you from putting your romantic plans into action and enjoying them.

PDE-5 inhibitors function as a blood thinner and reduce blood pressure. Therefore they can be dangerous for those who already have low blood pressure, suffer from cardiovascular problems, or are taking conflicting medications.

If this is the case, you are advised to consult a doctor before swallowing a pill containing a PDE-5 inhibitor. If the blood pressure drops too low, it can be life-threatening. Men with cardiovascular problems belong to the group of few, for whom these medications can be harmful. The same goes for men who have suffered a heart attack or stroke. Likewise, men, who use antihypertensive agents or other blood thinners should probably refrain from taking this type of medication.

Beware of overdose and exaggeration!

More dangerous than the medicine itself is the enthusiasm tempting you into exaggeration.

Keep in mind that a higher dose of erection medication does not lead to increased potency, but only strengthens the potential side effects. One to be particularly concerned about is a permanent erection. If an erection lasts longer than two hours, it becomes very painful. After 4-6 hours, it may leave permanent damage if not treated by a doctor by then.

But that’s not all we are talking about when we say exaggeration. Overdoing it with the sexual activity can simply overburden the heart and entire cardiovascular system. So, if you take Viagra or Cialis, Levitra, Spedra or any of the generic ED meds for the first time after a sexual drought, don’t get carried away with excitement all through the night. Nobody wants the thrill to end in a heart attack.

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This article does not aim to cover the full range of side effects of erectile dysfunction treatments but provides an overview of the most common ones. Always consult a doctor if you are not sure whether the remedy is suitable for you or if you have unexpected concomitant symptoms. You can find the package leaflet of each medication on the related page on our website.

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Complete a simple online health questionnaire

Select preferred treatment

Our GP will review and approve your prescription

Next day delivery

You will receive your medication the next day