Is Viagra safe?

Reviewed by our clinical team

Sildenafil, which is sold under the brand name Viagra, is an oral medication that is used to treat erectile dysfunction (ED). Whilst many people are aware of what Viagra does in relation to erectile behaviour, some people have questions about its safety.

In this article, we are going to aim to address these concerns by looking more closely at how Viagra works, who can take Viagra, how to take it safely and any risks associated with its use.

How does Viagra work?

An erection, which is the hardening of the penis, occurs when the sponge-like tissue in the penis fills with blood. When the brain becomes aroused, signals are sent to the penis, leading to the release of a chemical called cGMP. cGMP relaxes particular muscle cells in the tissue of the penis, and this allows an increase in blood flow to the area.

Erectile dysfunction is the inability to get or maintain an erection. This can be due to a variety of reasons including certain medications, stress, mental health conditions, hormone problems, narrowing of the blood vessels and high blood pressure.

Viagra treats erectile dysfunction by temporarily increasing the blood flow to the penis when sexually excited. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors and works by relaxing the blood vessels in the penis. It does this by reducing the effect of PDE5, which is an enzyme that is released after ejaculation and causes cGMP to break down, leading to the loss of an erection. Viagra stops cGMP from being broken down, meaning that the arteries in the penis stay relaxed,  thereby increasing blood flow to the penis.

It usually takes 30-60 minutes for Viagra to take effect so it should be taken at least one hour before you intend to have sex.  It stays in your bloodstream for four-six hours,  so you  should be able to get an erection anytime during that time as long as you are aroused. It will not give you an erection if you are not aroused.

How to take Viagra safely

Taking Viagra is generally straightforward and once you have taken it for the first time, you’ll likely have a better idea of how your body responds to it. For best results and to reduce the likelihood of any side effects, it is best to follow the following guidelines when taking Viagra:

• Only take Viagra once a day
• Swallow tablets whole with water or juice
• Ideally, take on an empty stomach
• Take an hour before you want to have sex
• Refrain from drinking too much alcohol before taking it
• Don't taking Viagra with recreational drugs including, poppers (amyl nitrate), ecstasy, cocaine, and LSD
• Do not take Viagra if you are taking certain heart medication containing nitrates (e.g. GTN spray, ISMN or ISDN tablets, Nicorandil) or if you are using certain creams to treat anal fissures. Taking this alongside Viagra can cause a fatal reaction.

How much Viagra should I take?

Viagra comes in three different strengths; 25mg, 50mg and 100mg. Viagra connect is the over the counter version of Viagra 50mg.

The standard recommended dose of Viagra is 50mg to be taken as and when you need it. However, some people take different dosages of Viagra following consultation with their GP or pharmacist. 

Is Viagra dangerous?

Whilst Viagra is used safely by millions of men across the globe, it can be dangerous if used incorrectly. Viagra can be dangerous if you take more than prescribed, if you have certain medical conditions, or take certain medications. Taking Viagra with recreational drugs, and in particular, poppers can cause collapse due to a sudden, extreme drop in blood pressure.

Can I take Viagra?

Viagra can be used by most men over the age of 18 who are experiencing erectile dysfunction.

When is it not safe to take Viagra?

There are some people that Viagra may not be suitable for. You should speak to your doctor or pharmacist before taking Viagra if you are on any medications that may be causing erectile dysfunction or if you have:

• Ever previously reacted to sildenafil or any other medicine
• Low blood pressure
• Angina (chest pain) and take nitrates for this
• A serious liver or heart condition
• Sickle cell anaemia
• Multiple myeloma
• A stomach ulcer
• Recently had a stroke, heart attack or other heart condition
• A rare inherited eye disease such as retinitis pigmentosa
• A penis deformity such as Peyronie's disease
• Ever had an erection that has lasted for more than four hours

You als must not take Viagra or other PDE5 inhibitors if you take or are prescribed any of the following:

• Nitrate containing medication to treat or prevent chest pain such as: GTN spray or tablets, isosorbide mononitrate, isosorbide dinitrate, nicorandil
• GTN cream to treat anal fissures (rectogesic)
• Certain HIV medications - there are quite a few that interact so please ask your specialist about this
• Riociguat for the treatment of PAH

What are the side effects of taking Viagra?

Like all medications, Viagra can cause side effects in some people. Common side effects of Viagra include:

• Headaches
• Dizziness
• Nausea
• Flushing, including hot flushes
• Indigestion
• Nasal congestion (stuffy nose)
• Blue tinge to vision or blurred vision

Serious side effects from Viagra are rare, occurring in less than 1 in 1,000 people. Serious side effects of Viagra include:

• Chest pain
• A prolonged and a painful erection lasting several hours (priapism)
• An allergic reaction (wheezing, breathing difficulties, or swelling of the eyelids, face, lips, or throat)
• Serious skin reactions such as skin peeling, swelling, and blistering of the mouth, genitals and around the eyes
• Fits (seizures)
• Tightening of the throat
• Palpitations
• Sudden decrease or loss of vision
• Blood in the urine

So, is it safe to take Viagra?

Generally speaking, yes, Viagra is safe to take for most men over the age of 18. However, it isn’t suitable for everyone as certain conditions and medications can increase the likelihood of dangerous side effects. Even if it's thought to be safe for you to take Viagra, it might not suit you or cause (serious) side-effects or interact with medication or supplements.

If you are experiencing erectile dysfunction and feel Viagra would be beneficial, you should always consult your doctor, or a pharmacist first and then proceed with their advice and recommended dose.
Viagra can be prescribed but it is also available without a prescription in the form of Viagra Connect. This type of Viagra can be purchased over the counter and online.

If you’d like to learn more, why not take a look at our guide to what Viagra does that you may find helpful. You can also request ED treatments discreetly, following a simple online consultation with our clinicians, which comprises of a short medical questionnaire to assess your suitability for medication.

References

https://www.nhs.uk/medicines/sildenafil-viagra/about-sildenafil-viagra/
https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/
https://www.nhs.uk/medicines/sildenafil-viagra/how-and-when-to-take-sildenafil/
https://www.nhs.uk/medicines/sildenafil-viagra/common-questions-about-sildenafil/
https://www.nhs.uk/medicines/sildenafil-viagra/who-can-and-cannot-take-sildenafil/
https://www.nhs.uk/medicines/sildenafil-viagra/side-effects-of-sildenafil/
https://www.medicines.org.uk/emc/product/8725/pil
https://www.medicines.org.uk/emc/product/7141/smpc#gref