But you also deserve to do that safely. Different brands may not work the same way. Check with your doctor immediately if any of the following side effects occur: Less common Arm, back, or jaw pain blurred vision chest pain, discomfort, tightness, or heaviness chills. You can buy it from a store-based pharmacy or reputable online pharmacy with a prescription. Precautions It is important that you tell all of your doctors that you take tadalafil. The same increase in nitric oxide that helps penile muscles relax also opens up blood vessels, leading to a drop in blood pressure. Proper Use Use tadalafil exactly as directed by your doctor.Three Cialis mg to 5 mg subjects, three Cialis 5 mg subjects and two placebo subjects discontinued study participation due to an adverse event (AE). Nasal congestion was the only AE leading to discontinuation reported by more than one subject (two subjects in the tadalafil to 5 mg group). About Cialis. We have good news for you: generic Cialis, used to treat erectile dysfunction (ED) and enlarged prostates, just hit pharmacies. Prices for the generic, known as tadalafil, are more than 50% less than those of brand-name Cialis. As more men are able to afford tadalafil and treat their ED, it’s likely that many will have questions.  · Cialis® also contains tadalafil. If you take too much tadalafil or take it together with these medicines, the chance for side effects will be higher. If you experience a prolonged erection for more than 4 hours or a painful erection for more than 6 hours, contact your doctor immediately. This condition may require prompt medical treatment to.