Sildenafil Teva
From £3.99
Sildenafil works well for most men with erectile dysfunction, but if sildenafil is not working, it is often down to common, fixable factors such as taking it at the wrong time, using it with a heavy meal or too much alcohol, not having enough sexual stimulation, or having an underlying health issue that needs attention.
For men in the UK who are using sildenafil for ED (Erectile Dysfunction), or considering it and want to know what to do if it seems ineffective, it usually makes sense to try it several times under the right conditions before deciding that it does not work for you.
This guide explains how sildenafil works, the genuine reasons it may not be effective, what dosage and timing mistakes to avoid, and when other factors such as stress, medication interactions, counterfeit tablets, or conditions affecting blood flow could be getting in the way. Because ED is common and treatable, getting clear on the real cause matters, it can help you avoid misuse, reduce risk, and know when to adjust your approach, consider other ED treatments, or speak to a prescriber for proper medical advice instead of simply trying again.
Key things to know
- Sildenafil requires sexual stimulation to work. You still need to be sexually aroused and sexually stimulated, and it does not increase libido or cause an erection on its own.
- Timing, food, and alcohol are the most common reasons it underperforms.
- Never take more than 100mg, or more than one dose, in a 24-hour period.
- If it does not work after several correct attempts, that is a reason to speak to a prescriber, not to keep increasing the dose yourself.
How Sildenafil Is Supposed to Work
Sildenafil is a PDE5 inhibitor. It works by relaxing blood vessels and improving blood flow to the penis, but only in response to sexual stimulation, it does not trigger an erection by itself. It typically starts working within 30 to 60 minutes, is usually taken one hour before sex or sexual activity, and stays effective for about four hours within its active window. If there wasn't enough stimulation, or not enough time had passed, that alone can look like the medication "not working" when it simply didn't get the chance to. Understanding this mechanism is often the first step in troubleshooting, since it rules out a whole category of misunderstanding before moving on to genuine causes.
The Most Common, Fixable Reasons It Does not Work
- Taken too soon after a large or high-fat meal, which can delay absorption and slow the medicine's onset of action.
- Not enough time allowed between taking it and sexual activity.
- Alcohol involved, which can both reduce effectiveness and independently affect performance.
- Insufficient sexual stimulation, since sildenafil enhances a response rather than creating one from nothing.
- Judged after a single attempt rather than being tried on several occasions under the right conditions.
Before concluding sildenafil is not working, it is worth checking these factors. Taking it on an empty stomach or after a light meal, avoiding alcohol, allowing enough time, and ensuring adequate sexual stimulation can all help give the medicine the best chance to work. A useful approach is trying it under genuinely optimal conditions two or three times before drawing any conclusions, since a single attempt under less than ideal circumstances does not tell you much about whether the medication itself is effective for you.
Is It the Wrong Dose?
Sildenafil comes in 25mg, 50mg and 100mg strengths. 50mg is the usual starting dose, and some men need 25mg or 100mg depending on response and tolerability, a decision made with a prescriber, not independently. If 50mg genuinely is not working after several correctly timed attempts, your prescriber may assess whether a higher dose is appropriate, potentially increasing to 100mg under supervision.
Never take more than 100mg in a single dose, and never more than one dose in any 24-hour period.
Taking 200mg or more does not improve effectiveness and significantly increases the risk of side effects, including a dangerous drop in blood pressure.
This is consistent with NHS guidance on sildenafil, which confirms 100mg as the maximum single dose.
Underlying Health Conditions
Certain health conditions can reduce how well sildenafil works, and some chronic health conditions can affect blood flow so not enough blood reaches the penis for a stronger erection, including cases where atherosclerotic heart disease can obstruct blood flow to the penis.
Examples include uncontrolled diabetes, cardiovascular disease, heart disease, high blood pressure, nerve damage, low testosterone, changes in hormone levels or testosterone levels, issues with thyroid function, and other physical conditions or neurological conditions such as venous leak.
These do not necessarily mean sildenafil can not work for you, but they may mean the underlying cause needs addressing alongside treatment, or that a different approach is more appropriate.
This is worth discussing with a prescriber rather than guessing. Identifying underlying conditions and risk factors can help them recommend the most appropriate treatment.
Could It Be a Counterfeit or Poor-Quality Product?
If sildenafil consistently does not work despite correct use, and you didn't obtain it through a regulated pharmacy, it is worth considering whether the product itself was genuine.
Counterfeit or substandard ED (Erectile Dysfunction) medications are a real problem with unregulated online sellers, and a product with too little active ingredient, or none at all, would understandably seem "not to work" regardless of any other factor.
Buying through a GPhC-registered pharmacy tha tcarries out a genuine clinical assessment is one of the best ways to reduce this risk.
Psychological Factors
Stress, anxiety, depression, and relationship issues can all affect sexual arousal, which sildenafil depends on to work. In some cases, psychological factors are the primary cause of erectile difficulties, and addressing these factors can improve sexual function, so medication alone may not fully resolve them.
Counselling or psychosexual therapy, alongside or instead of medication, can be genuinely effective, and is not a sign that medication has failed you.
Performance anxiety specifically can create a self-reinforcing cycle, where worrying about whether it will work becomes part of what stops it working, which is worth recognising rather than only focusing on the physical side.
Medication Interactions
Several medicines can interfere with sildenafil, and certain medications can also worsen erectile function themselves, including alpha-blockers, some antidepressants, and antihistamines.
Sildenafil must never be combined with nitrate medications or recreational nitrates, due to a serious blood pressure interaction, and people with certain heart conditions, low blood pressure, or chest pain during sexual activity should seek medical advice before using sildenafil.
Always tell your prescriber about everything you are taking, including over-the-counter products, supplements, and grapefruit juice, so they can check for interactions before you start, rather than discovering a problem after treatment hasn't worked as expected.
Lifestyle Factors
Smoking and heavy alcohol use can reduce blood flow, worsen ED symptoms, and make sildenafil less reliable by directly undermining the mechanism it relies on. Neither means sildenafil definitely won't work for you, but both are important factors to consider if you are troubleshooting why it is not working as expected for you specifically. This is not about blame, plenty of men who smoke or drink do find sildenafil effective.
Lifestyle changes, including stopping smoking, reducing alcohol, eating well, and staying active, can also improve erectile function.
Sildenafil Fever: Is This a Real Side Effect?
Fever is not a commonly recognised direct effect of sildenafil. If you experience a fever while taking it, this is more likely to be unrelated, such as a separate illness, rather than caused by the medication itself.
It is still worth mentioning to a pharmacist or prescriber, particularly if it is persistent or you are unsure of the cause, rather than assuming a connection either way.
Generic Sildenafil vs. Branded Viagra
Generic sildenafil and branded Viagra contain the same active ingredient at the same strengths and are held to the same UK safety and effectiveness standards. Some people feel they respond differently, although there is no evidence that branded Viagra is more effective than generic sildenafil when both contain the same active ingredient and dose.
Other Erectile Dysfunction Treatments Worth Knowing About
Sildenafil is not the only way to treat erectile dysfunction. Depending on what is causing your symptoms and how you respond, a prescriber may suggest a different medication approach, such as tadalafil (including a daily, lower-dose option, and it can last up to 36 hours), vardenafil in standard tablets, or avanafil/Spedra, may work more quickly than some other PDE5 inhibitors in some people.
| Treatment | Price from |
|---|---|
| Sildenafil (generic) | £3.99 |
| Viagra (branded) | £27.99 |
| Tadalafil (generic) | £34.99 |
| Cialis (branded) | £44.99 |
| Cialis Daily | £89.99 |
| Vardenafil (generic) | £27.99 |
| Levitra (branded) | £32.99 |
| Avanafil (Spedra) | £22.99 |
| Viagra Connect | £21.99 |
| Cialis Together | £16.99 |
Prices update live and may change, check the current figures before ordering. If oral options are not effective, vacuum erection devices can help create an erection, and penile implants are a longer-term surgical option. If one PDE5 inhibitor does not suit you, this does not mean none will, different medications in this class can behave differently for different people.
When to See a Prescriber Rather Than Try Again
- You have tried sildenafil correctly (empty stomach, adequate time, adequate stimulation) on several occasions without success
- You are tempted to exceed 100mg or take more than one dose in 24 hours
- You suspect an underlying health condition, medication interaction, hormonal issue, or other risk factors
- You want to explore an alternative treatment
Erectile dysfunction is common and treatable, and a single unsuccessful attempt, or even several, does not mean treatment has failed. It usually means it is time for a proper review rather than repeated guessing.
If sildenafil is not working despite correct use, a clinical review can help identify the cause and whether a different treatment may be more suitable.
Start your ED assessment and our clinical team can review your current dose, help identify the right treatment, or decide if a different medication may suit you better.
Medical Disclaimer
This page provides general information about why sildenafil may not work and possible next steps. It is not a substitute for personalised medical advice, diagnosis, or treatment.
Dosing decisions, including any change in strength, are always confirmed by a prescriber or pharmacist based on your individual circumstances.
Never exceed 100mg or take more than one dose in 24 hours.
Seek urgent medical advice if you develop a painful erection that lasts more than four hours.
If you have questions about your treatment, side effects, or interactions with other medicines, speak to your prescriber, pharmacist, or GP.
