Sildenafil

What is Sildenafil?

Sildenafil, brand name Viagra, is a treatment for erectile dysfunction. It works in combination with sexual stimulation to help a man achieve and maintain an erection for long enough to engage in sexual activity.

How does Sildenafil work?

Sildenafil works by relaxing the blood vessels that supply the penis. This improves blood flow, making it easier to achieve and maintain an erection. When you first start taking Sildenafil, you may not experience effects straight away. It is recommended that you trial Sildenafil for approximately 1 week, before you switch medications if it doesn’t work for you. 

How effective is Sildenafil?

Sildenafil is effective for 65% of people who take it. Erectile dysfunction can vary a lot between people. It is common to have to try several different ED medications before finding the one that works best for you. To help you, an ED Trial Pack is available that contains a selection of the most popular ED medications at a range of doses. 

How long does Sildenafil take to work?

Sildenafil takes 30 minutes to 4 hours to work. Sildenafil does not automatically give you an erection, but it makes it easier to obtain an erection following sexual stimulation. 

How long does Sildenafil last?

Sildenafil can last for up to 5 hours. This does not mean that you will have an erection for 5 hours, but that you should be able to get an erection at some point within 5 hours. 

Sildenafil misuse

Sildenafil is a convenient and effective treatment for erectile dysfunction, but can be dangerous if overused or if used recreationally. It is important to remember that Sildenafil is a prescription drug and should never be used if not prescribed to you personally by a doctor. Purchasingany medication from an unregistered source is extremely risky, as you can never be sure of what exactly you are taking, so though it may seem like a hassle, it is well worth obtaining it on prescription. Sildenafil should never be used where it is not necessary, as improper use puts you at risk of increased side effects and dependence.

How to take Sildenafil

Always take Sildenafil as instructed by a doctor or pharmacist, who will also instruct you on your dosage. Swallow one tablet whole with a glass of water approximately an hour before sexual activity. Sildenafil may take longer to work if you have just eaten a heavy or fatty meal. If you feel that your dose is too weak or too strong, your doctor may alter your dosage. Do not take Sildenafil more than once a per day, as taking too much Sildenafil increases the likelihood of experiencing side effects.

Sildenafil dosage & Sildenafil starting dosage

The recommended starting dose of Sildenafil is 50 mg taken once daily. This can be increased or decreased if necessary. Increasing the dose past 100 mg will not increase the effectiveness of Sildenafil.

Can Sildenafil tablets be crushed or divided?

Sildenafil tablets should be swallowed whole with a glass of water and should not be crushed or split.

Can Sildenafil be taken daily?

Sildenafil can be taken daily if necessary, but should not be taken more than once a day. It is only effective in the instance of sexual arousal.

Sildenafil side effects

Like all medications, Sildenafil can cause side effects in some patients. If you experience any of the following rare but serious side effects, stop taking Sildenafil and seek medical help immediately:

• An allergic reaction with symptoms including wheezing, difficulty breathing and swelling of the eyelids, face, lips or throat
• Chest pain. If this occurs during or after intercourse, get into a semi-sitting position and try to relax, and do NOT use nitrates to treat your chest pain.
• Prolonged or sometimes painful erections
• Sudden decrease or loss of vision
• Serious skin reaction including severe peeling, swelling, blistering of the mouth, genitals or skin around the eyes, and fever
• Seizures or fits

Headaches may affect 1 in 10 people who use Sildenafil. Other common side effects (up to 1 in 10 cases) include:

• Nausea
• Facial flushing
• Hot flush
• Indigestion
• Colour tinge to vision
• Blurred vision
• Visual disturbance
• Congested nose
• Dizziness

Uncommon side effects (affecting up to 1 in 100 side effects) include:

• Vomiting
• Skin rash
• Eye irritation
• Bloodshot or red eyes
• Seeing flashes of light
• Visual brightness
• Light sensitivity
• Watery eyes
• Pounding or rapid heartbeat
• High or low blood pressure
• Muscle pain
• Sleepiness
• Reduced sense of touch
• Vertigo
• Ringing in the ears
• Dry mouth
• Blocked sinuses
• Sinusitis
• Upper-abdominal pain
• Gastro-oesophageal reflux disease
• Blood in the urine
• Pain in the arms or legs 
• Nosebleed
• Feeling hot or tired

Rarely (1 in 1,000), the following side effects may be experienced:

• Fainting
• Stroke
• Heart attack
• Irregular heartbeat
• Temporary decreased blood flow to parts of the brain
• Tightening of the throat
• Numb mouth
• Bleeding at the back of the eye
• Double vision
• Blurred vision
• Abnormal sensation in the eye
• Swelling of the eye or eyelid
• Small particles or spots in your vision
• Seeing halos around lights
• Dilation of the pupil of the eye
• DIscolouration of the white of the eye
• Penile bleeding
• Blood in the semen
• Dry nose
• Swelling of the inside of the nose
• Feeling irritable
• Sudden decrease or loss of hearing

Contraindications

Do NOT take Sildenafil if:

• You are allergic to sildenafil or any of the other ingredients of this medication
• You have severe heart or liver problems
• You have recently had a stroke or heart attack
• You have or have had low blood pressure
• You have a family history of degenerative eye diseases
• You have ever had a condition involving loss of vision due to damage of the optic nerve from insufficient blood supply known as non-arteritic ischemic optic neuropathy (NAION)
• You do not have erectile dysfunction
• You are female

You should inform your doctor and take particular care when taking Sildenafil if:

• You have sickle cell anaemia, leukaemia or multiple myeloma
• You have problems with your heart
• You currently have a stomach ulcer or a bleeding problem such as haemophilia

Drug interactions

Before taking Sildenafil, tell your doctor or pharmacist if you are taking any other medications, including those purchased over the counter without a prescription. Do NOT take Sidenafil in combination with:

• Any other treatment for erectile dysfunction
• Medicines containing nitrates, such as glycerol trinitrate for angina, or nitric oxide donors, such as amyl nitrate
• Riociguat, used to treat pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension
• PDE-5 inhibitors for the treatment of pulmonary arterial hypertension

Additionally, inform your doctor if you are taking:

• Protease inhibitors, such as for the treatment of HIV
• Alpha-blockers

How to cope with Sildenafil side effects

The most common side effects of Sildenafil are headaches, flushing and stomach upset, which may affect around 1 in 10 people. Headaches can usually be managed by drinking plenty of fluids and taking over-the-counter painkillers, such as paracetamol or ibuprofen, where necessary. If you experience facial flushing, try and stay cool by applying  cool compress, breathing deeply and trying to relax. If any of these side effects are particularly severe or prolonged, or if you frequently experience stomach upset when taking Sildenafil, speak to a doctor or pharmacist for advice. A doctor may recommend an alternative ED treatment.

Sildenafil and alcohol

Drinking alcohol can inhibit your ability to get an erection. In order to experience the best results of Sildenafil, you are recommended to limit the amount of alcohol you drink.

Can I take Sildenafil with other ED medications?

Sildenafil should not be taken in combination with other erectile dysfunction medications.

Do recreational drugs affect Sildenafil?

It can be dangerous to take Sildenafil with recreational drugs, including stimulants such as ecstacy or cocaine, hallucinogens such as LSD and former-legal highs such as mephedrone. Sildenafil should NOT be taken in combination with poppers (amyl nitrates), as this can have a dangerous effect on the heart.

Sildenafil vs Viagra

Viagra is the brand name of Sildenafil used for treatment of erectile dysfunction. Both contain the active ingredient sildenafil and work in exactly the same way, although the generic Sildenafil is significantly cheaper.

Why choose Sildenafil?

Sildenafil (brand name Viagra) is the most well-known and popular treatment for erectile dysfunction. Generic Sildenafil is significantly cheaper than the branded Viagra and works in exactly the same way. Alternative PDE-5 inhibitors have since been developed and are available on prescription in the UK, the most recent being Spendra (Avanafil) which is fast acting. Different treatments may be better suited to different people, and a doctor or the ED Trial Pack will be able to help you decide which is best for you.

Brands of Sildenafil

A doctor will write a prescription for this medication using the medical name ‘Sildenafil’, but a pharmacist is free to supply any available brand. Viagra is the brand name for Sildenafil prescribed for treatment of ED in the UK, and Revatio is the brand name used for treatment of pulmonary hypertension. The brand Kamagra is not legal in the UK, and can therefore only be purchased illegally through websites that are not registered pharmacies. Doing so runs the risk of purchasing counterfeit medication which can be dangerous.

Alternative treatments

In the UK, most treatments for erectile dysfunction require a prescription, however, Viagra Connect has recently become available over the counter. Like Sildenafil, Tadalafil (Cialis) and Vardenafil (Levitra) are PDE-5 inhibitors that work by increasing blood flow to the penis in the event of sexual stimulation. Cialis has a longer action time, and can remain effective for up to 36 hours. The new, fast-acting variant called Avanafil (Spedra) takes as little as 15 minutes to take effect and has a similar duration of action to Viagra and Levitra.

Is Sildenafil safe for long-term use?

Sildenafil is safe for long-term use, although this may lead to psychological dependency. Erectile dysfunction often has a psychological cause, such as anxiety, depression or stress, and continued use of treatments such as Sildenafil may mask these issues and prevent the patient from pursuing more effective, long-term help.

Is Sildenafil a cure?

Sildenafil  will not cure erectile dysfunction, the root cause of which is often psychological. However, it can help to relieve the stress and anxiety associated with ED in the short term.

Can women take Sildenafil?

There is little evidence to suggest that Sildenafil has any affect on female libido or sexual enjoyment. However, it can be used to treat pulmonary hypertension in women.

Is it safe to buy Sildenafil online?

It is safe to buy Sildenafil online from a registered pharmacy such as Dr Felix. It is a prescription-only medication and should never be purchased online through any website that does not require a private prescription. Howeve, Viagra Connect contains 50mg sildenafil and is available over the counter without a prescription. 

Can I buy Sildenafil without a prescription?

Sildenafil is only available in the UK with a prescription and should not be purchased prescription-free online. Viagra is the branded version of Sildenafil - it is available without a prescription (over the counter) as Viagra Connect.

Sources

• Patient Information Leaflet
• NHS > Viagra
• Drugs.com > Sildenafil