Viagra is FDA-approved to treat erectile dysfunction ... Ages 18 and up (IV injection): 10 mg IV bolus injection three times a day Ages 1 year or older, 20 kilograms (kg) or less: 10 mg by ...

Each medication has its own dosage meter. Viagra doses are 25 milligrams (mg), 50 mg, and 100 mg. Cialis and tadalafil doses are 5 mg, 10 mg, and 20 mg. Cialis also has a lower dose of 2.5 mg that ...

Viagra costs $90 to $139 per tablet. Generic sildenafil can range from $2 to $10 per pill, depending on the manufacturer and dose.