Cialis is a brand name for Tadalafil, a phosphodiesterase inhibitor used to treat erectile dysfunction (ED), urinary tract problems in men, and most recently it was approved for the treatment of pulmonary hypertension. The drug was originally manufactured exclusively through the Eli Lilly pharmaceutical company, but the rights were sold in 2008 http://health.usnews.com/health-news/family-health/heart/articles/2008/10/28/cialis-may-help-ease-pulmonary-hypertension.html Cialis is the third drug approved by the Food and Drug Administration to treat erectile dysfunction, and is available in 5 mg, 10 mg, and 20 mg dose tablets.

Cialis was approved for the treatment of ED by the FDA, on November 21, 2003.http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm118686.htm It was discovered through a joint project between ICOS and GlaxoSmithKline, studying compound IC351. In 1994, ICOS researchers recognized the potential for compound IC351 to be used in the treatment of erectile dysfunction. After ICOS received a patent on the compound, clinical trials began in 1995. After GlaxoSmithKline left the project, ICOS joined with Eli Lilly in 1998. During clinical trials of Cialis, it was demonstrated that the drug was effective for up to 36 hours. Eli Lilly bought out ICOS in 2007, continuing production of Cialis exclusively through their company. http://www.msnbc.msn.com/id/22558665/

Cialis is marketed as both a daily and 36-hour drug, meaning its effectiveness can span a 36-hour window, allowing men more flexibility when it comes to deciding on when to be intimate with their partner. If Cialis is taken daily, patients will not have to take the medication in anticipation of sex, because it will already be present in their system. http://www.msnbc.msn.com/id/22558665/

Tadalafil works by inhibiting phosphodiesterase, which increases the level of cyclic guanosine monophosphate (cGMP). The increase in cyclic guanosine monophosphate levels increase the blood flow to the erectile tissue, thus enabling men with ED to maintain an erection. http://medical-dictionary.thefreedictionary.com/tadalafil

Common side effects of Cialis (Tadalafil) include:

• Headache
• Indigestion
• Muscle pain
• Hot flashes/flushing
• Nasal congestion

The side effects of Cialis typically clear up within a few hours of taking the drug. It is recommended that any man experiencing an erection lasting longer than 4 hours while taking Cialis, seek immediate medical attention. http://www.cialis.com/Pages/index.aspx