Cialis is the trade name and generic name for tadalafil tablets, tadalafil tablets normally work after 30 minutes of administration. Tadalafil tablets are a western medicine used to treat erectile dysfunction in men. The medication requires sexual stimulation for the drug to take effect and should not be used in women. The drug should be taken before sexual intercourse, independent of eating, and at least 30 minutes before sexual intercourse to ensure that the drug works. Tadalafil tablets should be taken at a maximum frequency of once a day. The use of tadalafil may cause adverse reactions such as headache, back pain, and indigestion. People who are allergic to the ingredients of tadalafil tablets are prohibited from taking the drug. Patients taking any form of nitrates are prohibited from taking the drug. Tadalafil tablets are prescription drugs and should be taken under the supervision of a doctor to avoid medication risks.