Combined use could lead to additional lowering of blood pressure, possibly to unsafe levels. What important information should you know about Cialis? Brand names Why is this medication prescribed? There are many other treatments for erectile dysfunction. It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. · But on average, its effects start to lessen 2 to 3 hours after you take a dose. The typical dose for once-daily Cialis for ED is milligrams (mg) to 5 mg. When used as needed for ED, the usual. Tadalafil (Cialis) is taken by mouth either as needed before sexual activity or once daily for erectile dysfunction (ED).It’s also taken once daily to treat symptoms from an enlarged prostate (benign prostatic hyperplasia, or BPH).Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side effects of this medication include . Drug information provided by: Merative, Micromedex® US Brand Name. Adcirca; Cialis; .