Cialis

What is Cialis?

Cialis is the brand name for the erectile dysfunction (ED) treatment tadalafil. Cialis was developed by the pharmaceutical company GlaxoSmithKline but is now owned by Eli Lilly.

What is Cialis used for?

Cialis is used to treat erectile dysfunction also known as impotence. ED is the inability to achieve an erection or maintain an erection long enough to ejaculate. Cialis is only available via prescription.

How do erections normally take place?

Before we can discuss ED, we need to first understand how normal erections work. A male gets erect when he gets sexually stimulated. Normally, seeing something stimulating causes males to get sexually aroused. In addition to the sense of sight, other senses like hearing, smelling, touch, and taste can also cause sexual arousal. In many situations, the mere memory of a stimulating experience can cause a male to get sexually aroused. There are some sensory stimuli in the memory-whether something seen, touched, felt, heard, tasted, or smelled that triggers sexual arousal. Notice that all this sexual stimulation is focused and originate in the biggest sexual organ of all-the human brain. Once the male is sexually aroused by external stimuli, the brain sends chemical signals to the penis. These signals trigger the introduction of nitrous oxide from endothelial cells and nerve endings. The nitrous oxide makes its way to the region of the penis termed the corpus cavernosum. This is the region of the penis where there are spongy muscle tissues which can inflate and deflate depending on the volume of blood flow. In this region, the nitrous oxide binds with cyclic guanosine monophosphate (cGMP) found in this area of the body. Once these two compounds bind, cGMP works to relax the blood vessels in this area and the spongy tissue fills up with blood. This process results in an erection. The erection is normally maintained until the male ejaculates or the stimulation wears off and blood flow to this part of the body subsides. A key part of the erection process is override of PDE5. This is an enzyme that blocks cGMP from binding with nitrous oxide. Normally, PDE5 binding is in effect. This is why males don't normally walk around with full-time erections. A key part of the erection process overcomes normal PDE5 operations enough so cGMP binds with nitric oxide to boost blood flow for an erection.

What causes ED?

There are two main categories of causes for ED: mental and physical causes. Both interrupt normal physical processes that result in erection. Mental causes of ED normally involve the reduction or interruption of the sexual arousal process. Instead of observed or experienced stimuli producing the right chemical reactions in the body which results in an erection or sustained erection, the brain experiences sexual arousal but fails to send the right signals to the body for the erection process to take place. Common mental or psychological reasons for ED range from relationship stress, past trauma, overall stress levels, and other psychological strains. The end result is the same: a disconnect between sexual stimulation in the brain and the body's physical response.

The other major category of ED causes is physical. Identified physical causes include, but are not limited to:

Diabetes' blood vessel constriction effects
Damage to or clogging in blood vessels-including artherosclerosis
Heart conditions
Multiple sclerosis (MS)
Elevated blood pressure
High blood serum levels for low density lipoproteins or LDL cholesterol
Tobacco smoking
Parkinson's
Heavy drinking or alcoholism
Being obese as determined by body mass index (BMI)
Lower than normal testosterone levels
Physical damage to the pelvic area's nerve network due to surgery or physical injuries
Scar tissue formation inside the penis (Peyronie's disease)
Metabolic Syndrome (caused by the combined presence of the following: elevated cholesterol levels, too much fat in the body's mid-section, high levels of insulin, and high blood pressure)
Chemical effect of certain classes of antidepressants or antianxiety medication
Chemical effect of medication for prostate enlargement or prostate cancer
Chemical effect of other medications

How does Cialis provide relief from the symptoms of ED?

Cialis' main chemical Tadalafil is a PDE5 inhibitor. This compound's chemical structure is very similar to cGMP. Instead of PDE5 binding to cGMP, the PDE5 binds to Tadalafil instead due to its close chemical similarity to cGMP. This frees up a higher amount of cGMP to bind with nitric oxide. If enough cGMP molecules in the penis' corpus cavernosum bind with nitric oxide, the smooth muscles in this region of the body relax and blood flow increases. The spongy tissue of the corpus cavernosum then fills up with enough blood to achieve an erection or maintain a sufficiently strong erection until ejaculation.

How did Cialis get discovered?

GlaxoSmithKline (formerly known as Glaxo Wellcome) discovered Cialis through a partnership between the pharmaceutical giant and the biotechnology firm ICOS. ICOS started studying a compound named IC351 in 1993. IC351 is an inhibitor of the PDE5 enzyme. The year after, Pfizer, the company that discovered Sildenafil (brand name: Viagra) announced that sildenafil, a PDE5 inhibitor, caused erections in men participating in a heart medicine clinical study. Originally, ICOS researchers were not studying IC351 for its ED treatment capabilities. The Pfizer announcement helped them shift their focus for IC351. As a result, ICOS patented IC351 in 1994 and development proceeded until the compound won FDA approval. Interestingly enough, Glaxo let its 50/50 profit sharing agreement with ICOS lapse in 1996 because ED treatment was not in Glaxo's field of concentration. In 1998, ICOS partnered up with Eli Lilly and Company to continue the development of IC351, the compound that will later be known as tadalafil and branded as Cialis. Cialis was approved by the FDA as a treatment for ED in 2003.

Why take Cialis instead of Viagra or sildenafil?

Although Viagra broke new ground and became world famous, there is a sizable number of men who don't experience optimal results with Viagra due to the fact that sildenafil has a half-life of only four hours. Cialis, on the other hand, can continue to work for as long as 36 hours. Keep in mind that this doesn't mean the men who take Cialis remain erect for that length of time. They only remain erect for as long as they are sexually stimulated. Cialis' blood-flow boosting effects remain active for a longer period than its competition Levitra and Viagra. Instead of having to time their intake of ED medication prior to sexual contact, men can use Cialis as a once-daily ED treatment.

What are the side effects of Cialis?

The most common side effects of Cialis, like other PDE5 inhibitors, are: runny nose, flushing, aching muscles, back pain, indigestion, blurred vision, hearing loss, and headache.

Which drugs should not be taken with Cialis?

Tadalafil must not be taken (at least within a window of 48 hours) with chemical compounds that decrease blood pressure like nitrates, nitrites, and similar chemical compounds.