Viagra

Viagra contains sildenafil citrate, which blocks the enzyme phosphodiesterase type 5 (PDE5). When a man is sexually aroused, nitric oxide is released in the penis and raises levels of a messenger called cGMP, which relaxes the smooth muscle and lets blood flow in. Sildenafil stops cGMP from being broken down as quickly, so the erection is easier to achieve and keep. The UK SmPC describes the indication as erectile dysfunction in adult men, meaning difficulty getting or maintaining an erection firm enough for satisfactory sex. Sexual stimulation is still needed: the tablet does not cause an erection on its own.

What is offered here is a generic sildenafil made outside the UK and listed under the Viagra name; it is not the Viatris-branded product. Seven strengths are shown: 25 mg, 50 mg, 100 mg, 120 mg, 130 mg, 150 mg and 200 mg, each in packs of 10, 20, 30, 60, 90, 120, 180, 270 or 360 tablets. The UK SmPC sets the maximum recommended single dose at 100 mg, so the 120 mg, 130 mg, 150 mg and 200 mg strengths are above that limit.

Viagra film-coated tablets of 25 mg, 50 mg and 100 mg hold a UK marketing authorisation, first granted in 1998 and now held by Viatris, and they are prescription-only medicines (POM). Viagra Connect 50 mg is licensed as a pharmacy medicine (P), which a pharmacist can supply after checking that it is suitable; it is limited to one 50 mg tablet a day. A 50 mg orodispersible film version of Connect also exists. The imported tablets sold on this page are not covered by any of these UK licences.

The usual starting dose in the SmPC is 50 mg, taken as needed roughly an hour before sex. Depending on how well it works and how it is tolerated, this may be raised to 100 mg or lowered to 25 mg; no more than one dose should be taken in 24 hours. Taking it with food can delay the effect, because absorption is slowed by around an hour on average. A 25 mg starting dose should be considered for men with severe kidney impairment or liver impairment such as cirrhosis, and for those taking CYP3A4 inhibitors, for example erythromycin, ketoconazole or itraconazole. Men on alpha-blockers for blood pressure or prostate symptoms should be stable on them first and may also start on 25 mg. Older men need no adjustment.

Any nitrate medicine for angina, whether a spray, tablet or patch, and amyl nitrite ("poppers") can drop blood pressure dangerously when taken with sildenafil, and the same applies to riociguat, so these combinations are forbidden. Nicorandil carries the same risk. The SmPC also rules it out after loss of vision in one eye from NAION, in severe liver impairment, with blood pressure below 90/50 mmHg, after a recent stroke or heart attack, in inherited retinal disorders such as retinitis pigmentosa, and in men for whom sexual activity is inadvisable, such as those with unstable angina or severe heart failure. Ritonavir is not advised alongside it. Women and under-18s are outside the licence.

Headache is very common. Flushing, dizziness, indigestion, a blocked nose, nausea, hot flushes and visual disturbances, including a blue tinge to vision and blurring, are also among the most frequently reported reactions. An erection lasting more than four hours needs urgent medical help to avoid permanent damage. Any sudden loss or change of vision means stopping the tablets and seeing a doctor straight away.

Whether sildenafil is suitable, and at which dose, is a decision for the doctor or prescriber after looking at your heart health and other medicines.