Nitrates come as tablets, sublingual under the tongue tablets, sprays, patches, pastes, and ointments. Patients who have a condition called “left ventricular outlet obstruction” from valvular problems or heart muscle enlargement may get side effects such as fainting or light-headedness. More serious side effects may include a drop in blood pressure or an erection that lasts longer than four hours. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine. While each PDE5 inhibitor differs slightly, they’re very similar in treating erectile dysfunction. There are two different ways to take tadalafil, either daily or on an as needed basis.tadalafil Used for Benign Prostatic Hyperplasia, Erectile Dysfunction erectile dysfunction (ED) benign prostatic hyperplasia, or BPH). Tadalafil (Cialis) is available . 20 mg The cost for these different strengths depends on whether you have insurance, your individual plan coverage, and your treatment plan. For example, Cialis . The recommended starting dose for Cialis intended for once daily use is mg, take at the same time each day, without regard to timing of sexual activity. This may be increased to 5mg/day based on need and tolerability. May be taken with or without food. Cialis is available as a generic, under the name tadalafil. 3.