Cialis: Description and Uses
Cialis is a trade name for tadalafil, a PDE5 inhibitor used to treat erectile dysfunction. The drug was originally developed biotechnology researchers ICOS before being further developed and marketed by Lilly ICOS, LLC, a joint venture of ICOS and Lilly. It was cleared for sale in the US by the Food and Drug Administration as the third in the new wave of treatments for male penile impotence spearheaded by sildenafil citrate (Viagra). The unique feature of Cialis is the drug’s long half life which means it is effective for a full 36 hours after ingestion. Because of this it is known as “the weekend pill|”.
How Does Cialis Work
Like its forerunners, Viagra and Levitra, Cialis works by inhibiting the enzyme PDE5. This enzyme increases the amount of cGMP which is responsible for regulating blood flow to the penis. It does not cause erection without sexual stimulation, which is needed to launch release of nitric oxide in the smooth muscle of the penis. Tadalafil differs substantially from both sildenafil and vardenafil only by its much longer half-life of 17.5 hours, which is responsible for its long-lasting effectiveness.
What does Cialis look like?
Cialis is sold as yellow, almond shaped tablets in strengths of 2.5, 5, 10, and 20 milligrams. The tablets are film-coated and imprinted with the letter C and the strength in milligrams. Newer formulations are sold in a dosage specifically tailored to regular daily use.
Cialis Administration and Dosage
Cialis is available only on prescription and should be taken exactly as prescribed. Taking it in larger doses or more frequently than recommended could cause adverse effects. Cialis is intended to be taken immediately before sexual activity is intended. It will then assist in achieving and maintaining an erection under the influence of sexual stimulation. The usual starting dose of Cialis is 10 mg, which may be increased incrementally until the required effect is obtained. More recently, Cialis has been prescribed to be taken daily as a smaller dose, providing fulltime assistance with erections whenever required. The usual starting dosage for daily Cialis is 2.5 mg, which may be increased to 5 mg if this is needed and does not lead to problematic side effects.
Potential Adverse Effects of Cialis
The side effects of Cialis are similar to those of Viagra and Levitra. They include redness in the face or neck, congestion in the upper respiratory tract, memory problems, headache, dyspepsia or diarrhea and muscle pain in the lower back and legs. There are a number of more serious side effects which are extremely rare. However if they are encountered, you should stop taking Cialis immediately and call a doctor at once. These effects include sudden changes in vision or hearing, tinnitus, chest pain or shortness of breath, tachycardia, swelling in the hands or feet, convulsions, fainting or priapism.
What other drugs interact with Cialis?
Before taking Cialis you should discuss any other medication you are taking with your doctor. Drugs which may have a dangerous interaction with Cialis include antibiotics such as erythromycin, clarithromycin or dalfopristin, antifungals like itraconazole, voriconazole ketoconazole, antidepressants including nefazodone, any barbiturates, anti-retroviral drugs and others used to treat HIV or AIDS, including darunavir, efaverenz, etravirine, nevirapine, fosamprenavir, tironavir and indinavir.