It can occur in men of all ages, including those in their 20s, 30s and 40s. Like other medications, it can sometimes cause adverse effects. One additional factor that can affect how long Viagra lasts is your age. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. Cialis lasts longer.Viagra adalah obat untuk mengatasi disfungsi ereksi atau yang dikenal dengan sebutan pil biru atau obat kuat ini tersedia dalam bentuk tablet 25 mg, 50 mg, dan mg.. Viagra memiliki bahan aktif sildenafil sitrat. Obat ini bekerja dengan dengan cara meningkatkan aliran darah ke penis setelah adanya rangsangan seksual. Viagra® is available in three doses: 25 mg, 50 mg and mg. The 25 mg dose is the lowest available dosage of Viagra®, which is only used if you are unable to tolerate higher doses. The 50 mg dose is the “normal dose” or starting dose of Viagra® for most men.  · 3 Answers. Viagra works in response to sexual stimulation to increase the blood flow to the penis leading to an erection. Viagra does not result in an erection without sexual stimulation. When a man is aroused, muscles in the penis relax to allow this greater blood flow. Viagra helps to elevate the levels of a substance (cyclic guanosine.