Talk to your doctor about which dosing schedule is right for you. You should only be treated with one of these products at a time. Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient. What alternatives can I use for erectile dysfunction? You can buy it from a store-based pharmacy or reputable online pharmacy with a prescription.Cialis and generic Cialis, known as tadalafil, are available from online services, along with other ED treatment options for people looking to buy ED medication online. A generic version of Cialis® (tadalafil, Eli Lilly) tablets ( mg, 5 mg, 10 mg, 20 mg) for the United States market has been annouced by Teva Pharmaceuticals. Roman sells the following versions of Cialis: Generic: available in tablets of 5, 10, and 20 milligrams (mg), starting from $11; Daily Generic: available in doses of .