Cialis, a member of PDE5 enzyme inhibitors family, works by blocking up the enzyme that causes an erection to go flaccid. At present, Cialis is marketed in around 40 countries and is available thru prescription in pharmacies on five continents. Initially, Cialis was originated by Icos, a small biotechnology company in the United States. Icos has formed 50/50 joint venture with American Pharmaceutical Giant, Eli Lilly & company. The partnership is known as Lilly Icos .

Cialis is available only by prescription. The most common side effects associated with taking Cialis are headache, stomach upsetting, backache, muscle ache, dizziness, nausea, numbness, allergic reaction, difficulty in breathing; swelling on face, lips, tongue, or throat, tingling in chest, arms, neck, or jaw during sexual activity. The serious fallouts related with Cialis are chest pain, irregular heartbeat and vision changes. If any of these side effects occur, stop using Cialis, and do get emergency medical help, if you have sudden vision loss.

Remember that Cialis doesn't protect against sexually transmitted diseases (STDs), including HIV. It is detrimental to take Cialis if someone is already taking nitrates, often recommended for chest pain, as this may result into a sudden or unsafe drop in blood pressure. Don't drink alcohol in excess with Cialis, as this may raise the chances of dizziness or lowering of blood pressure.

Take Cialis as prescribed by the physician. Don't take Cialis in larger quantities. Cialis should be taken with water, and it can be taken with or without food. Normally, Cialis is taken only when required, just before sexual practice. Cialis can help achieve an erection when sexual stimulation takes place. Avoid alcohol as it can raise side effects of Cialis. Don't make use of any other impotency drug including alprostadil or yohimbine without discussing with the medical doctor.