Viagra and how it reacts with other medicines

Some prescription medicines, when taken together, can interact with each other. It can alter the effects of either drug. For example, one treatment may increase or decrease the effectiveness of the other. This can result in side effects or may mean that one of the medicines doesn’t do its job.

This is no less true for Viagra. The active ingredient in Viagra is Sildenafil, which belongs to a class of medicines called PDE5 inhibitors (Phosphodiesterase-5 inhibitors). They work by widening the blood vessels to allow for more blood flow to the penis. However, this can affect blood flow across the body which is why it can react with other medicines.

Here are some of the main interactions you should know about.

Viagra and heart medications

Viagra can react with medicines used to treat and prevent heart conditions such as medicines for the treatment or prevention of:

• high blood pressure (hypertension)
• angina - chest pain caused by poor blood flow to the heart
• heart attacks
• heart failure
• coronary artery disease

Doctors can prescribe some of these medicines for other conditions. For instance, some alpha-blockers can be prescribed for prostate enlargement (BPH). However, they are mostly used for heart problems.

Below are examples of these medicines that may react with Viagra.

*Also used for an enlarged prostate

What these medicines have in common is that they all lower blood pressure. Sildenafil, the active ingredient in Viagra, is often also used to treat high blood pressure in the lungs (pulmonary arterial hypertension). However, when taken with another heart medication, this can cause a sudden drop in your blood pressure.

The main sign of low blood pressure is dizziness when sitting or standing up too quickly. It can sometimes result in fainting.

If you take any medicines like these, speak to your doctor before using Viagra. They may need to adjust your dose beforehand.

Viagra and poppers

Poppers is the common name for a medicine called amyl nitrate. It is a recreational drug that belongs to the same family as nitrates used for heart conditions. However, poppers are most commonly used to relax the walls of the anus and vagina for sex.

Like Viagra, they dilate the blood vessels in these areas, which can reduce your overall blood pressure. So like heart medicines, if you take these together, it can cause low blood pressure.

If you use poppers, do not take Viagra at the same time.

What other drugs react with Viagra?

Other medicines may cause interactions, which could be dangerous. Here are just a few examples.

These are just some of the medicines that can interact with Sildenafil. For the full list of drug interactions, please refer to the British National Formulary (BNF) guidelines for Viagra here or ask your healthcare provider.

It’s hard to say whether herbs and supplements are safe to take with other medications, as the herbal market is not as regulated as the over-the-counter and prescription medications.

There are some herbal products that are well-known to cause interactions, such as St John’s Wort, but it is always best to just check with your doctor or pharmacist.

You should also avoid using any natural aphrodisiacs or products labelled as “herbal Viagra” as these will likely cause side effects.

Do not take multiple medicines for impotence together. Not only will this not improve your symptoms, but it can also cause serious side effects such as a prolonged erection (priapism).

Do not take it with any of the following impotence medicines:

• Tadalafil (Cialis)
• Vardenafil (Levitra)
• Avanafil (Spedra)
• Alprostadil (Caverject)

You should also not take Viagra with other medicines that contain Sildenafil, such as Viagra Connect, Aronix or Revatio.

Priligy is a popular treatment for premature ejaculation that contains dapoxetine. It was originally used as an antidepressant and a side effect is lowering your blood pressure. As this is the main mechanism of action in Viagra, you cannot take both together as it could cause a dangerous drop in your blood pressure.

If you take any other medicines, there are ways you can improve your ED without taking Viagra. A healthy lifestyle will improve blood flow and help with erection problems.

Other ED treatments, such as penis pumps or surgery, may be more suitable for those who take medication.

However, always speak to your doctor. They may be able to adjust your Viagra dose or the dosage of your current medicines to help find a solution that works for you.