The erectile dysfunction treatment Viagra, and its generic version Sildenafil, are safe to use for the vast majority of men who suffer from impotence, but there are a number of situations where their use is unsuitable and carries an increased risk of side effects. These include situations where someone is taking one or more separate medications that interact with the treatment, or those where someone has a medical condition that might be exacerbated by its use. 

The term ‘contraindication’ refers to medical conditions that might make use of these medications unsuitable.

Before you start treatment with Viagra or Sildenafil, it is really important that you inform your prescribing clinician about any of these issues so they can provide a safe and effective treatment.

Knowing if you can take Viagra

Even if there are some known contraindications related to these medications, your doctor may decide on balance that the benefits outweigh the risks and provide you with a prescription that minimises the risks involved. It is likely that this will include a smaller dosage than is standard, to see if the benefits of the treatment can be experienced without issue. 

If Viagra or Sildenafil is likely to be unsafe for you to take, your prescriber will suggest a different approach to treatment instead. This might be a different medication altogether (for example one that uses a different active ingredient, like Caverject) or a non-medicated approach, like talking therapy or lifestyle change.

Contraindications for Viagra and Sildenafil

Not all contraindications are serious. In some instances, it might just mean a slightly increased risk of side effects. But in other cases, the risk might be more serious.

Is it safe to take Viagra or Sildenafil?

Your doctor will be able to provide you with all the relevant information before you start treatment and you can also refer to the patient information leaflet that comes with your medication.

Is Viagra dangerous? 

You should avoid using Viagra or Sildenafil if any of the following relates to you: an allergy to anything in the medication, severe heart or liver problems, recent stroke or a heart attack, have low blood pressure, inherited eye diseases or have loss of vision due to non-arteritic anterior ischaemic optic neuropathy (NAION).

The following conditions may also make this treatment unsuitable: sickle cell anaemia, leukaemia, multiple myeloma, deformity of the penis, Peyronie’s Disease, problems with your heart, stomach ulcers, bleeding problems, protease inhibitors or alpha-blocker therapy.

When not to take Viagra

There are some other situations where the treatment isn’t likely to be effective, and taking it may introduce unnecessary risk. These include being in a difficult relationship, alcohol or drug abuse and cases where erectile dysfunction is not present.

Difficult relationships and Viagra

Relationships are complex and a functioning sex life is not always the primary cause for concern. In these cases, your doctor may decide that dealing with these issues is more pressing, and a different type of solution, such as talking therapy, might be advised instead.

Viagra and alcohol or drug dependency

If your consumption of alcohol or drugs is at the root of your erectile dysfunction problem, then a doctor may decide that prescribing these treatments might be of little use, and that tackling these primary issues is more of a priority. Not only can substance abuse cause erectile dysfunction, but they may also render the effects of drugs like Viagra and Sildenafil useless. Your doctor may instead refer you to treatments that deal with the underlying causes of the condition.

Viagra and recreational use

It is presumed by some that erectile dysfunction treatments such as Viagra and Levitra act as aphrodisiacs and can therefore be used for those that have not been diagnosed with erectile dysfunction. These treatments, however, do not provide sexual arousal and should not be taken recreationally. They are also not suitable for use in women. If you are a woman who is experiencing sexual dysfunction issues you should speak with your doctor about an appropriate treatment.

Avoiding the risks of Viagra contraindications

Contraindications can be severe and dangerous and as such you should only use these treatments under supervision from your doctor (or on the advice of your pharmacist in the case of Viagra Connect). It’s important to stick to the instructions, and not raise or lower the dose yourself. Speak to your prescriber if you feel like the dose or treatment you’re on isn’t working, or is causing side effects.

The risk of contraindications is very high when using counterfeit medications, that are typically bought online from unregistered sources. These can contain dangerous substances and different levels of active ingredients to those stated. So it’s important to only use licensed treatments acquired from a registered pharmacy. In the UK, online providers must be registered with the GPhC to be able to issue treatment. You should normally be able to find a logo showing the registration details on their website, but if you can’t, contact them to ask for it.

Page last reviewed:  07/12/2020