The table below summarizes the typical dosages for tadalafil: Indications of Tadalafil:. Obesity Additionally, certain risk factors increase the risk of ED, such as smoking , lack of exercise, and drug or alcohol use. The drug is approved for use in adults. Just make sure you take it at the same time every day. In trials investigating Cialis, the majority of participants receiving the drug experienced a significant improvement in ED and maintained an erection. You can use Cialis on a daily basis at a lower dosage.Cialis is a prescription medication containing the active ingredient tadalafil. Cialis belongs to a group of medications known as phosphodiesterase-5 (PDE-5) . Tadalafil is in a class of drugs called phosphodiesterase-5 (PDE5) inhibitors and is available in a generic form often called generic Cialis. Tadalafil has been on the . Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side effects of this medication include headache and indigestion. Tadalafil .