Kamagra Effervescent is marketed as an effervescent sildenafil product, commonly listed in a 100 mg strength. Sildenafil is a PDE5 inhibitor used to treat erectile dysfunction (ED) by increasing penile blood flow during sexual stimulation. Treatment expectations should be realistic. Sildenafil does not increase sexual desire, and it will not produce an erection automatically. Sexual stimulation is necessary for it to work. With standard sildenafil treatment, effects commonly begin within about 30–60 minutes, although individual responses vary.