Well known ED medication Viagra, and the generic version Sildenafil, have proven to be a highly effective and well tolerated treatment for erectile dysfunction. In general, it can be taken with some other medications without much risk, but as is the case for all medications, there are some prescription and non-prescription drugs it shouldn’t be mixed with.

Before you start treatment with Viagra, Sildenafil or Viagra Connect, your prescribing doctor or pharmacist will need to know of any other medications that you are currently taking or have recently taken. This should include any supplements or herbal treatments, or any drugs you’ve taken recreationally. They will also need to know about any other conditions or allergies you have in order to ensure this treatment is safe for you.

What are Viagra interactions?

Interactions describe how different substances interact in the body. It is not always possible to predict how these will develop as everyone reacts differently to each specific treatment, let alone a mixture of them. There are, however, known interactions that can either heighten the risk of side effects for sildenafil or present serious health risks.

Interactions for Sildenafil

PDE-5 inhibitors like Viagra and Cialis are generally well tolerated and safe to use alongside many other treatments. But there are some medications it should never be combined with. For example there is a very serious risk for people taking nitrates, a type of medication prescribed to treat angina or heart problems.

If you are taking other medications that might make use of Viagra unsuitable, there are other options available.

Talking therapy or lifestyle changes, to address the potential causes of ED, can work in some cases. Examples include counselling, making changes to your diet, giving up smoking and cutting down on alcohol, and increasing the amount of exercise you do.

PGE1 or prostaglandin treatments may be recommended in some cases where PDE5 inhibitors are either ineffective or unsuitable. These include Caverject (an injection), MUSE (a urethral suppository) and Vitaros (a cream). As these medications are not ingested and applied locally, system interactions tend to be less likely. 

Viagra and other medications 

Once you have informed your prescribing clinician of any other treatments you are currently or have recently taken, they will be able to tell you of the risks involved, if there are any. In cases where there is a serious risk of interaction, a prescriber may recommend against using PDE5 treatment. It’s important to let them know, if you’re already using Sildenafil (or Viagra or Viagra Connect), and are prescribed a new treatment for a separate condition, so they can make it’s still safe for you to take Sildenafil.

The patient information leaflet that comes with your medication will list all known interactions, as well as contraindications and side effects.

Do not take this medication alongside the following: nitrates (including amyl nitrate) or riociguat.

Your doctor may decide that another treatment would be more suitable if you are also taking any of the following: protease inhibitors or alpha-blocker therapy.

Viagra can be taken with or without food, although large meals may slow the effects of the drug. It is recommended that you avoid consumption of grapefruit juice at the same time as Viagra as it has been known to increase the risk and severity of side effects.

Sildenafil and alcohol

There aren’t any specific interactions between Viagra and alcohol that have been noted. However, alcohol can make ED worse and might lead to Viagra becoming less effective. If you are planning on drinking while taking these treatments, it’s important to keep to sensible levels.

Page last reviewed:  23/07/2020