Safety information

Viagra can cause side effects. And men with certain health issues may be unable to take it.

Not everyone will get side effects when using Viagra. But it’s still important to know what the side effects are, and to speak to a doctor if notice anything unusual.

Seek immediate medical advice if you experience anything that might be a sign of an allergic reaction, such as breathing problems, wheezing, or swollen face, eyes, lips or throat. If you get chest pain, get into a half-sitting position and relax. You should speak to a doctor as soon as you can if this happens.

If you get an erection that won’t go away and lasts for more than four hours, go to hospital.

You should also seek medical attention immediately if you develop sudden sight problems, a serious skin reaction, or a fit or seizure.

Other side effects include:

Very common (1 in 10 people or more): Headache.

Common (1 in 10 people or less): Nausea, flushing in the face, hot flushes, digestion problems, stuffy nose and problems with vision including blurriness, changes in colour and disturbances.

Uncommon (1 in 100 people or less): Being sick, rash on the skin, irritated or bloodshot eyes, eye pain, brightness or flashes in vision, being sensitive to light, watering eyes, palpitations, fast heartbeat, high or low blood pressure, pain in the muscles, sleepiness, reduced sense of touch, vertigo, tinnitus, dry mouth, blocked sinuses, inflammation inside the nasal airways, pain in the upper abdomen, acid reflux, blood in the urine, arm or leg pain, nosebleed, feeling hot or tired.

Rare (1 in 1,000 people or less): Feeling faint, stroke, heart attack, irregular heartbeat, short-term loss of blood flow to parts of the brain, tightness in the throat, loss of feeling in the mouth, bleeding at the back of the eye, double vision, loss of sharpness of vision, strange sensation or swelling in the eye, particles or spots in vision, seeing halos around lights, pupil dilation, discolouration of the white of the eye, bleeding from the penis or in semen, dry nose, intranasal swelling, becoming irritated more easily, and loss of hearing. The leaflet notes that unstable angina and death have been reported rarely in men using Viagra. Most, but not all, of these cases, involved men with previous heart problems, so it is not possible to determine whether these were connected to the medicine.

The leaflet contains more detailed information, and can be accessed here.

You shouldn’t take Viagra if:

you’re a woman
you don’t have erectile dysfunction
you’re already using another treatment for erectile dysfunction
you’re allergic to anything in it (see below)
you’re taking one or more nitrate medicines (used in angina)
you’re using nitric oxide donors (such as amyl nitrate or poppers)
you’re taking riociguat (a drug used in pulmonary arterial hypertension)
you have severe heart or liver problems
you have recently had a heart attack or stroke
you have low blood pressure
you have an inherited eye disease such as retinitis pigmentosa
you have non-arteritic anterior ischaemic optic neuropathy (NIAON).

Let your doctor or pharmacist know before taking Viagra if:

you have sickle cell anaemia, leukemia or multiple myeloma
you have a deformity of the penis, such as Peyronie’s disease
you have heart problems
you have a stomach ulcer
you have haemophilia
you are lactose intolerant
you are taking alpha-blockers.

Your doctor also needs to know if you are taking any other medicines, as some may interfere with or be affected by the function of Viagra.

Drinking excessive amounts of alcohol can make erectile dysfunction worse, and as a result make less Viagra less effective.

Viagra contains: sildenafil, microcrystalline cellulose, calcium hydrogen phosphate (anhydrous), croscarmellose sodium, magnesium stearate, hypromellose, titanium dioxide (E171), lactose monohydrate, triacetin, and indigo carmine aluminium lake (E132).

The ingredients of Sildenafil tablets can vary according to the manufacturer. Please refer to the leaflet that comes with your medicine for a full list of ingredients.