Tadalafil tablets are usually available in pharmacies, but such medications are prescription medications that require a prescription from a doctor for purchase. Tadalafil is used for the treatment of erectile dysfunction in men and belongs to the class of 2-generation PDE5 inhibitors. By selectively inhibiting PDE5, it enhances the nitric oxide (NO)-cGMP pathway and elevates cGMP levels and leads to the relaxation of penile cavernous smooth muscle, which results in the production of a natural erection in response to sexual stimulation in patients with erectile dysfunction. Patients can take effect about half an hour after taking it. It is important to note that patients suffering from high blood pressure and heart disease are not allowed to take tadalafil, which may cause life-threatening conditions, and secondly, tadalafil should not be used in conjunction with any form of nitrates, which may cause postural hypotension, which in turn may be life-threatening. The use of tadalafil may cause adverse reactions such as headache, back pain and indigestion. It needs to be taken under the supervision of a specialist and should not be chosen on your own.