Cialis is the brand name of the FDA approved drug tadalafil. As Cialis, it is used in treating erectile dysfunction (ED) in men; as Adcirca, tadalafil is used in treating pulmonary arterial hypertension. Cialis belongs to a class of drugs called PDE5 inhibitors. They stop the degenerative attack by cGMP-specific phosphodiesterase type 5 (PDE5) on proteins lining the smooth muscles in the penis.

Generic drugs are exact copies of branded drugs approved by the FDA which are manufactured by companies other than the one that had the drug patented and sold under its name. Such drugs are sold cheaper than their branded counterparts since they aren't completely developed from scratch and the cost of bringing them to the market is lower.cialis

Read on to find out more about this drug and its uses, discovery, manufacturing process, and side effects.

Common uses

On sexual arousal, the penis’s nervous tissues release Nitric 0xide (NO) and due to this, an enzyme producing a messenger called cyclic guanosine monophosphate (cGMP) is stimulated. cGMP has a relaxing effect on the muscles and blood vessels of the penis, allowing the blood to flow into the penis easily. In men with erectile dysfunction, PDE5 is in higher concentrations and performs a degenerative action on cGMP messenger, reducing blood flow to the penis. Cialis, as well as other PDE5 inhibitors, come in the way of this degenerative action.

Cialis has another common use as well: treating the symptoms of benign prostatic hyperplasia (BPH). It is a non-cancerous increase in the size of the prostate. Large nodules form in the transition zone of the urethra putting pressure on it. This leads to obstruction in urine flowing from the bladder, causing urination difficulty and an added urge to pass more urine at night. It is very common among men older than 50, nearly 45% develop BPH and 75% have it by the time they are 80. In 2008, the FDA approved the use of Cialis for BPH which was reported to be occurring along with ED in some men. Clinical trials have shown significant reduction in BPH symptoms as a result of Cialis treatment.


Cialis was discovered during a joint venture between GlaxoSmithKline (then Glaxo Wellcome) and ICOS in 1991. Further study was done by ICOS on a compound named IC351, a PDE5 inhibitor. In 1994, Pfizer accidently discovered that sildenafil, another PDE5 inhibitor, caused penile erection in clinical subjects undergoing tests for heart ailments. Seeing this, ICOS scientists tried using IC351 to treat ED. In 1996, ICOS’s contract with Glaxo lapsed and in 2000, Lilly ICOS LLC (joint venture between ICOS and Eli Lilly & Company) filed for FDA approval for IC351 under the name tadalafil. 3 years later, they were granted approval and began selling it under the brand name Cialis. The advantage Cialis has had over Viagra and Levitra is its highly increased half-life. Cialis’s half-life is roughly 17.5 hours compared to Viagra and Levitra's 4-5 hours.

Side effects and precautions

Side effects experienced while taking Cialis include headaches, back pain, muscle pain, flushing, runny nose, stomach ache, acid reflux, and burping. The side effects are mainly due to the vasodilation caused by Cialis. Most of the unwanted reactions usually go away in a few hours whereas muscular pain might reduce after 12 to 24 hours. In case the pain persists, patients should immediately discontinue taking Cialis and contact their doctor promptly.

Other rare cases of partial hearing and vision impairment were reported. Due to this, the FDA has directed the manufacturer to issue statutory warnings on the packaging as a precautionary measure.

A single, isolated case of a man having consumed Cialis with a prolonged erection (priapism) was reported in 2005. The patient did not have any other contributing signs of priapism and the erection was relieved after caverno-spongiosal shunting. In case of an erection lasting longer than 4 hours, medical help should be sought immediately to prevent permanent damage to penile tissue.

up-arrowSince Cialis has a transient effect on blood pressure, it is imperative that we know about dangerous interactions the drug can have with other medications. Organic nitrates and nitrites should not be consumed within 48 hours of consuming Cialis as this could lead to life-threatening hypotension (extremely low blood pressure). If patients with angina are unable to take organic nitrates since they have consumed Cialis and experience chest pain, doctors should be contacted at once. In the event of an emergency, medical personnel must be made aware of the consumption of Cialis as it could prove vital to saving the patient's life.

Doctors should be informed of other medications such as antibiotics, hypertension medicines, HIV meds, and other ED tablets before starting to take Cialis. Other medical conditions (especially heart ailments) and allergies must also be discussed with the doctor.