Drug Interactions With Sildenafil Medication

Drug Interactions With Sildenafil Medication
Published : Nov 02, 2022
Last Updated : Jan 25, 2024

Adult men with erectile dysfunction can be effectively treated with prescription drug sildenafil. Like other ED medications, sildenafil has various drug interactions that must be taken into account.

Some drug interactions take place when one medicine makes another drug have an unanticipated result. It is important to know that sildenafil interacts with medicines that lower blood pressure such as nitrates.

Alcohol and grapefruit juice also interact negatively with sildenafil tablets, producing negative side effects. Drug interactions can cause headaches, dizziness, and fainting. Call a doctor if you develop any of these symptoms.

By the age of 50, erectile dysfunction affects over 50% of males, and this figure rises with age.

For several men experiencing erectile dysfunction, sildenafil is a first-choice medicine to attain or maintain an erection. Nevertheless, heart disease, high blood pressure, and prostate issues are more common in men as they get old.           

Several medicines that are taken for treating these medical conditions interact with the sildenafil pill. It’s not just medication that interacts with the sildenafil pill but also alcohol and grapefruit juice can cause problems.

There are some sildenafil interactions that are serious and must be avoided completely.

Common drug interactions with sildenafil

Sildenafil which is also available as pulmonary hypertension medicine Revatio might interact with several medications. In this blog, you will learn about drug interactions with the sildenafil pill closely.

Before starting treatment with any medicine, inform your doctor once to know about drug interactions.


Nitrates are a class of drugs that treat various heart conditions such as chest pain.

Some common nitrates include isosorbide mononitrate (Monoket) and nitroglycerin (Nitrostat).

These medicines work by widening the blood vessels present throughout the body.

While these drugs increase the flow of blood to your heart, they also lower blood pressure.

Sildenafil also works by broadening your blood vessels. This medicine ensures proper blood flow to the male sexual organ for erection.

With Revatio, there is a more smooth flow of blood to the lungs. But when combined with nitrates, sildenafil causes side effects.

A sildenafil tablet taken inadvertently with nitrates might cause dangerously low blood pressure. Consumption of sildenafil when taking nitrates is not prescribed and should be strictly avoided.

In case, you are taking this combination of medicines then consult your doctor to know a safe ED treatment.


Alpha-blockers are effective in treating various health ailments like benign prostatic hyperplasia and high blood pressure. Some common alpha-blockers include tamsulosin (Flomax), alfuzosin (Uroxatral), and doxazosin (Cardura).

Just like sildenafil and nitrates, alpha-blockers also work in the body by relaxing your blood vessels. When alpha-blockers are combined with sildenafil pills, they can make you suffer from low blood pressure.

In case, you are already taking an alpha blocker, your doctor can prescribe you take low dose of sildenafil. Patients who take the sildenafil pill at present need to take a lower dosage of alpha-blocker. 

It is important to consult a doctor immediately when signs of low blood pressure are experienced like dizziness. Make sure to get immediate medical attention, if you feel as if you’re going to pass out.

Blood pressure medicines

Remember nitrates and alpha blockers tend to have more serious interactions with sildenafil pills. If you make the mistake of combining blood pressure medicines with nitrates & alpha-blockers, they can cause interaction.

When amlodipine, a calcium channel blocker, and sildenafil are taken together, they result in low blood pressure. Be cautious when taking angiotensin-converting enzyme, angiotensin II receptor blockers, and diuretics, which are all blood pressure medications. 

If you are taking any of these combinations then it is necessary to check your blood pressure more frequently. While experiencing low blood pressure, a doctor might adjust your dosage of sildenafil pill.

Medicines that affect liver proteins

Remember sildenafil is broken down by certain proteins which are present in your liver. Certain medications even obstruct or overstimulate these proteins which further affect levels of sildenafil in your body.

Some common examples of medicines that are responsible for causing higher sildenafil levels include ketoconazole, ritonavir, and clarithromycin. Such type of interaction can increase your risk of experiencing sildenafil’s side effects like flushing, headaches, and others.

In case, you are taking any of these medications then a doctor might prescribe to start with a low dosage of sildenafil.

A number of medicines and supplements can lower levels of sildenafil in the body including Rifampin, St. John’s wort, and carbamazepine. Sildenafil might not work well for you when all these treatments are combined.

If this happens, let your doctor know because he/she can adjust the dosage of medication.


Alcohol can interact with sildenafil pill in a number of different ways. Intake of alcohol can worsen your ED condition. When sildenafil is taken to treat ED conditions, alcohol can counteract its effects quickly.

Also, alcohol is responsible for widening blood vessels present in the body just like sildenafil. You have a higher chance of developing low blood pressure if you take a sildenafil pill together with alcohol. 

Additionally, males taking sildenafil pills and drinking alcohol experience severe side effects. Headaches and face flushes are frequent side effects of combining alcohol and sildenafil.

It is always recommended to abstain from drinking alcohol to cure your ED problem successfully. Thus, to discover how much alcohol is safe for you to consume, speak with your doctor once.