Drug Name
Cialis (Tadalafil)
Drug Uses
Cialis is a prescription medicine taken by mouth for the treatment of erectile dysfunction (ED) in men.
How Taken
Take Cialis exactly as your doctor prescribes. Cialis comes in different doses (5 mg, 10 mg, and 20 mg). For most men, the recommended starting Cialis dose is 10 mg. Cialis should be taken no more than once a day. Your doctor will prescribe the dose that is right for you.
Drug Class and Mechanism
Tadalafil is an oral drug that is used for treating impotence (the inability to attain or maintain a penile erection). It is in a class of drugs called phosphodiesterase inhibitors that also includes sildenafil (Viagra) and vardenafil (Levitra).
Erection of the penis is caused by the filling of the penis with blood. Filling occurs because the blood vessels that bring blood to the penis increase in size and deliver more blood to the penis, and, at the same time, the blood vessels that take blood away from the penis decrease in size and remove less blood from the penis.
Sexual stimulation that leads to an erection causes the production and release of nitric oxide in the penis. The nitric oxide causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP). It is the cGMP that is primarily responsible for increasing and decreasing the size of the blood vessels carrying blood to and from the penis, respectively, and causing the erection. When the cGMP is destroyed by another enzyme, phosphodiesterase-5, the blood vessels return to their normal size, blood leaves the penis, and the erection ends. Tadalafil prevents phosphodiesterase-5 from destroying cGMP so that cGMP stays around longer. The persistence of cGMP leads to a more prolonged engorgement of the penis with blood.
Tadalafil was approved by the FDA in November, 2003.
Missed Dose
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Storage
Store Cialis at room temperature between 59 and 86 F (15 and 30 C).
