For men who are taking Viagra (or Sildenafil) for erectile dysfunction, it’s very important to take it according to the directions given by the doctor or health professional who prescribed it. It’s also vital to adhere to the instructions in the patient information leaflet, to make sure that the risk of side effects is kept to a minimum, and that the treatment is as effective as it can be.

On this page, we’ll go through the directions men using Viagra should follow. These instructions also apply to different versions of the drug, including Viagra Connect and Sildenafil.

When should I take Viagra?

The best time to take Sildenafil is around 60 minutes before you plan to have sex. It takes roughly 30-60 minutes in most men to metabolise in the body and get to work. So if you take it one hour before you anticipate that you need it, this should give the drug ample time to become active in the body.

It should then stay active for enough time for you to have sex. The summary of product characteristics, or SPC for Sildenafil states that it produces an erectile response to sexual stimulation for 4-5 hours after taking it. If you find that it doesn’t last long enough, or takes a long time to work, speak to your prescriber about adjusting your dose.

Taking Viagra with food and alcohol

How long Viagra takes to kick in can also be affected by whether you eat a large meal at the same time as taking it, or just before. The more work your gut has to do to digest food, the less quickly it will be able to metabolise ther drug, so this is important to keep in mind. If you eat something before taking Viagra, try not to eat too much.

The same applies to different active ingredients, such as avanafil, tadalafil and vardenafil, that perform a similar function in the body.

In the Viagra directions you’ll also notice that it mentions not to drink too much alcohol when taking it. It’s not thought that alcohol interacts with Sildenafil specifically, but it can dull your sensitivity to arousal and make it harder for you to get an erection. One study published in 1976 suggested that low amounts didn’t have a significant effect on male sexual response,  but that larger amounts (1.5ml to 1.8ml per kg of body weight) did have a depressing effect.

In clinical trials, grapefruit juice has been shown to interact with Sildenafil and make the activity of the drug less predictable. This includes an increase in the risk of side effects, so you should avoid consuming this when using Viagra. 

How many Viagra tablets should I take?

Only ever take one tablet at a time. You should never take more than one Viagra in any 24 hour period. If you take one, but you don’t feel like it has worked well enough, talk to your prescriber. They may be able to increase your dose to something more suitable.

If you find yourself taking more than three sildenafil tablets a week, it might be worth considering a medication like Cialis Daily (tadalafil) instead, because this is designed to be taken every day.

What should I check for before I take Viagra?

It’s always recommended to read the leaflet before taking any medication to make sure it’s safe for you. You’ll also find some important info on Viagra side effects, and what to do if you encounter them.

Not everyone can take Viagra. People taking medicines for other medical conditions may be advised to start on a lower dose. The leaflet will have info on potential Viagra contraindications and interactions, so make sure your prescriber is aware of any other treatments you’re using during consultation. 

Check the packaging when you receive your treatment by post, or from the pharmacy. If the packaging is damaged in any way, contact the pharmacy you got it from to ensure it’s still safe to use. 

Take a look at the use by date on your Viagra box too. In most cases, it’s reasonable to expect to receive a medication with at least a year before the expiry date. If you receive a medicine with a short expiry date, contact your pharmacist.

Page last reviewed:  24/07/2020