How to Take Sildenafil: BNF Guidelines & Instructions

Sildenafil is an effective treatment for erectile dysfunction when taken correctly. Understanding proper dosage, timing, and administration ensures optimal results and safety. This guide covers everything you need to know about taking sildenafil according to BNF guidelines. EverydayMeds offers both generic sildenafil and branded Viagra, allowing you to choose the option that suits your needs and budget.

  • Take 25-100mg approximately 1 hour before sexual activity
  • Maximum one dose per 24-hour period
  • Can be taken with or without food (fatty meals may delay effect)
  • Sexual stimulation is required for the medication to work
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Not sure which one? Here's the honest comparison.

Sildenafil
~60 min
~4 hrs
you like to plan ahead
Tadalafil (as-needed)Most prescribed
~30 min
up to 36 hrs
you want a whole weekend covered
Tadalafil Daily
always active
continuous
you never want to think about timing
Vardenafil
~15–30 min
~8 hrs
you want the fastest onset

How ED treatment works in your body.

Increases blood flow

Increases blood flow

When PDE5 is suppressed, blood is able to flow more freely through the body—including to the (you guessed it) penis.

Increase erections

Increase erections

More blood flow to the penis means harder, more satisfying erections once you're sexually stimulated.

Detailed Sildenafil Administration Instructions

Standard Dosing Protocol

The typical starting dose of sildenafil is 50mg, taken approximately one hour before anticipated sexual activity. Your prescriber may adjust this to 25mg if you experience side effects, or increase to 100mg if the initial dose proves insufficient. It's crucial to take only one dose within any 24-hour period, regardless of the strength prescribed.

Timing and Food Considerations

Sildenafil can be taken with or without food, though high-fat meals may delay the onset of action. The medication typically begins working within 30-60 minutes, with peak effectiveness occurring around one hour after administration. Effects may last up to 4-6 hours, though this doesn't mean an erection will persist throughout this period.

How Sildenafil Works

Sildenafil belongs to a class of medications called PDE5 inhibitors. It works by increasing blood flow to the penis when you're sexually aroused. Importantly, sexual stimulation is still required – sildenafil won't cause an automatic erection. The medication simply helps your body respond more effectively to natural arousal.

Choosing Between Generic and Branded Options

At EverydayMeds, you can select either generic sildenafil or branded Viagra during checkout. Both contain the same active ingredient and work identically, with generic options typically offering cost savings. Your choice depends on personal preference and budget considerations.

Important Safety Reminders

Never exceed the prescribed dose or take sildenafil more than once daily. If you're taking nitrate medications for chest pain, sildenafil is contraindicated due to dangerous blood pressure interactions. Always inform your prescriber about all medications you're currently taking during your consultation.

What to Do If It Doesn't Work

If sildenafil doesn't provide the desired effect, don't increase the dose yourself. Contact your healthcare provider to discuss adjusting your prescription or exploring alternative treatment options. Factors like stress, alcohol consumption, or underlying health conditions can affect medication effectiveness.

What you need to know about erectile dysfunction

It's one of the most common conditions we treat, and one of the most treatable.

What is Erectile Dysfunction?
ED means finding it hard to get or keep an erection firm enough for sex. It's not unusual to have an off night; the point at which it's worth doing something is when it's happening regularly, or when it's starting to bother you.
How will I feel when I take ED medication?
For most men, nothing feels different day to day. The medication works in the background — when you're sexually aroused, it helps blood flow where it's needed, so erections come more easily and last longer. It doesn't cause arousal on its own. Some men notice mild, short-lived effects like a headache, facial flushing or a stuffy nose, which usually pass as the dose wears off.
Why do I need a prescription for ED medication?
ED treatments are prescription-only medicines in the UK because they aren't suitable for everyone — for example, alongside certain heart conditions or medications like nitrates. That's why we ask you to complete a short online consultation first. A UK-registered prescriber reviews your answers to make sure your chosen treatment is safe and right for you before it's dispensed.
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