Tell your healthcare provider that you take Cialis. Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient. Like the other details of your sex life, what works for you will be unique to your needs. Sexual activity may be a strain on your heart, especially if you have heart disease. Tadalafil is in a class of medications called phosphodiesterase PDE inhibitors. Like other medications for ED, tadalafil starts working quickly. Tadalafil was approved in in the United States for the treatment of pulmonary arterial hypertension [28] and is under regulatory review in other regions for this condition.Cialis Dosages. The most appropriate Cialis dose for you will depend on your needs, your healthcare provider’s assessment and how well you respond to the medication. Cialis is available in two forms: As a daily-use medication in dosages of mg and 5mg. For use as needed in dosages of 10mg and 20mg. Best prices for generic cialis on the Internet! The safest way is to ask your physician to try an alternate prescription. Detailed dosage guidelines and administration information for Cialis (tadalafil). Includes dose adjustments, warnings and . Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash.