What it is used for
- Treating erection problems (erectile dysfunction) in men
- Treating pulmonary arterial hypertension (high blood pressure in the lungs), prescribed and monitored by a specialist
How it is used
- Tablets are swallowed with water, only as prescribed by your doctor; your doctor decides the dose
- Chewable tablets are chewed, and orodispersible tablets are placed on the tongue to dissolve
- For erection problems: take it before sexual activity as your doctor directed; a heavy, fatty meal can delay its effect, and an erection only happens with sexual arousal
- Do not take more than your doctor has told you, and do not drink large amounts of alcohol with it
Possible side effects
- Headache, flushing or a blocked nose
- Indigestion or dizziness
- Temporary changes in colour vision (a bluish tinge) or blurred vision
- Rare but serious: a painful erection lasting many hours, sudden loss of vision or hearing, or chest pain; get medical help straight away
Who should not use it
- Taking nitrate medicines for angina such as glyceryl trinitrate or isosorbide, inhaled nitrites (poppers), or riociguat
- Severe heart disease where sexual activity is not advised, a recent heart attack or stroke, or very low blood pressure
- Previous loss of vision due to poor blood flow to the optic nerve, or inherited retinal disease
- Allergy to this ingredient or to any other ingredient in the product
Before and while using it
- Tell your doctor if you have heart, liver or kidney disease before starting
- If you get chest pain during sex, stop, do not take glyceryl trinitrate, get medical help straight away and tell them you took sildenafil
- Tell your doctor if you have a deformity of the penis or a blood condition such as sickle cell anaemia or leukaemia
- Do not buy this medicine from unreliable sources, and do not use more than one erection medicine together
Medicine interactions
- Nitrates, nitrites and riociguat: they can cause a dangerous drop in blood pressure
- Alpha-blockers such as doxazosin and tamsulosin, and blood pressure medicines, can cause dizziness and low blood pressure
- Some antifungals, antibiotics and HIV medicines such as ketoconazole, clarithromycin and ritonavir raise its blood level, and so does grapefruit
Pregnancy and breastfeeding
- Sildenafil for erection problems is not for women. If it is prescribed for pulmonary arterial hypertension, tell your doctor if you are pregnant or breastfeeding
How to store it
- Store at room temperature away from heat and moisture, out of the sight and reach of children.
Get medical help straight away if
- Your face, lips or tongue swell, or you find it hard to breathe.
- You get a severe rash, blistering or peeling skin.
- A side effect worries you or doesn’t go away: contact your doctor or pharmacist.
Questions about this medicine?
Talk to a doctor by video, or send your question by text.
Source: Standard international medicine references
This guide is general information and doesn’t replace advice from your doctor or pharmacist. Don’t start, stop or change a medicine without asking them, and always read the leaflet in the pack.