How to buy Cialis tablets in Pakistan? These tablets are available on the OpenTeleSale website, and you can go and purchase them from this page. How long does it take for Cialis to work? It takes about 30 minutes for Cialis to start working. That’s why it’s important to take it at least 30 minutes before sexual activity. The effects of Cialis can last up to 36 hours. So if you have time, take it a few hours before sex.