Viagra

What is it?

A phosphodiesterase type 5 inhibitor that increases blood flow into the penis available as blue, diamond- shaped, film-coated tablets in 3 strengths, all containing sildenafil as citrate. Available in 25mg, 50mg and 100mg strengths all marked VGR, PFIZER, and with strength.

Medical Uses

Male erectile dysfunction.

Dosage

Men, 50mg by mouth about one hour before sexual activity. Alter subsequent dosage depending upon response (maximum dose 100mg). No more than one dose per day. For elderly 25mg to start; subsequent doses may go up to 100mg as daily maximum.

Special Care

Sickle cell anaemia, leukaemia, multiple myeloma (a form of cancer), severely impaired kidney function, impaired liver function, abnormal anatomy of the penis, bleeding disorders, stomach ulcer.

Avoid Use

Boys, existing heart conditions where sexual activity is not advised, severe liver disorders, recent stroke or heart attack, low blood pressure, hereditary degenerative disorders of the retina of the eye. Possible interactions: amylnitrite, nitrates, ritonavir (do not use viagra), other therapies for the same condition, cimetidine, β-blockers, protease inhibitors, erythromycin, inhibitors of CYP 3A4, ketoconazole, grapefruit juice.

Known Side Effects

Dizziness, gastrointestinal upset, headache, blocked nose, flushes, disturbance of vision, pain in eyes and blood shot eyes, allergic reactions. In rare cases, prolonged erection or priapism (painful, abnormal persistent erection requiring medical treatment), serious cardiovascular effects including heart attack, angina, rapid or slow heartbeat, low or high blood pressure, transient ischaemic attack, palpitations, arrhythmias, haemorrhage, fainting.