If you’re looking for an effective erectile dysfunction treatment, sildenafil could be an option for you. This drug is one of the most commonly used active ingredients to treat erectile dysfunction and could help you to get and maintain an erection. Here’s some more information on it to help you decide whether it’s an option for you or not.

What is Sildenafil?

Sildenafil is the active ingredient found in Viagra – a treatment for erectile dysfunction (which involves being unable to get or maintain an erection). While Viagra is the best known erectile dysfunction medicine, it is a brand name and sildenafil is the main active ingredient and will work in the same way. It is simply a more cost effective option that you might like to consider.

How Does Sildenafil Work?

Put simply, sildenafil contains the active ingredient sildenafil citrate, which actively increases blood flow to the penis. This can help you to get an erection and to maintain an erection. Please note that sildenafil only works if you are sexually aroused. This medicine will not resolve any underlying issues causing difficulties getting an erection. It will also not increase your sexual desire.

Is Sildenafil Effective?

Studies have found that sildenafil will help erectile dysfunction in at least two out of three cases. It is a highly effective treatment for erectile dysfunction, which explains its wide use and popularity. You may find that its effects are reduced if you eat a large meal or have consumed more than two units of alcohol before taking it. If you find that sildenafil isn’t working for you, it is generally recommended that you try it eight times before seeking out an alternative erectile dysfunction treatment.

Do You Need a Prescription?

You don’t need a prescription to buy sildenafil. It is available over the counter as Viagra Connect in most pharmacies and can also be ordered online. Either way, you will need to answer a few questions to check that this treatment is suitable for you as an individual. When you buy sildenafil in store, you will simply have a short, face to face consultation. When you order online, this will take the form of a short online consultation.

How Long Does It Take to Work?

After taking sildenafil, you are likely to experience its effects within half an hour to an hour. Of course, you need to be aroused for it to work and to see its effects.

How Long Does It Last?

When you take sildenafil, you can find that its effects can last for up to six hours.

How Regularly Can You Use Sildenafil?

Sildenafil is safe to take daily. However, you should only take it once a day. You should not take more than one sildenafil tablet every 24 hours.


The most commonly recommended starting dose when taking sildenafil is 50mg. Of course, individual differences in age, height and weight, as well as the cause and the severity of your ED, may see you prescribed a lower dose (such as 25mg) or a higher dose (such as sildenafil 100mg). It’s important to note that the amount of sildenafil you take does not impact how long the treatment takes to work or how long the treatment works for. You should also note that taking higher doses of sildenafil, such as sildenafil 100mg uk, can come with an increased risk of developing side effects.

Side Effects

As with any medicine, sildenafil can have side effects. Here are some of the different ones to keep an eye out for. If you do experience any side effects when taking sildenafil, discontinue use and consult your doctor, who will be able to give further advice.

Common side effects

Alopecia; anaemia; anxiety; cough; diarrhoea; dizziness; fluid retention; gastrointestinal discomfort; gastrointestinal disorders; headaches; increased risk of infection; insomnia; nasal complaints; nausea; night sweats; pain; skin reactions; tremor; vasodilation; vision disorders.

Uncommon side effects

Arrhythmias; chest pain; drowsiness; dry eye; dry mouth; eye discomfort; eye disorders; eye inflammation; fatigue; feeling hot; gynaecomastia; haemorrhage; hypertension; hypotension; myalgia; numbness; palpitations; sinus congestion; tinnitus; vertigo; vomiting.

Rare side effects

Acute coronary syndrome; arteriosclerotic retinopathy; cerebrovascular insufficiency; glaucoma; haematospermia; hearing impairment; irritability; optic neuropathy (discontinue if sudden visual impairment occurs); oral hypoaesthesia; priapism; retinal occlusion; scleral discolouration; seizure; severe cutaneous adverse reactions (SCARs); sudden cardiac death; syncope; throat tightness.


As with many medicines, sildenafil can interact with other drugs, so you need to make sure that it is safe to take with any other drugs that you may be taking at the same time. If you are taking alpha-blockers (such as doxazosin or tamsulosin),  you should discuss this with your doctor. You should not take sildenafil if you are taking nicorandil or nitrates, such as GTN spray or isosorbide mononitrate tablets to treat angina. When ordering sildenafil, make sure that you have consulted your doctor or a pharmacist to ensure that it is a suitable treatment for you to try.


There are, of course, alternative erectile dysfunction options on the market if you find that sildenafil doesn’t work for you. Some of these include:

  • Tadalafil
  • Vardenafil
  • Avanafiil
  • Alprostadil
  • Testosterone replacement
  • Penis pumps
  • Penile implants
  • Psychological counselling
  • Many more

As you can see, sildenafil is a highly effective erectile dysfunction treatment that is a much more cost effective alternative to Viagra. It is effective in at least two out of three people and the results can last for a duration of time that is suitable for most. If you have any further questions, make sure to consult your doctor who will be able to guide you in the right direction.

Although all of our content is written and reviewed by healthcare professionals, it should not be substituted for or used as medical advice. If you have any questions about your health, please speak to your doctor.

Authored Apr 20, 2021 by Joseph Issac, MPharm
Reviewed Apr 27, 2021 by Prabjeet Saundh, MPharm