Take this tadarise 20 mg medicine within the dose and duration as advised by your doctor. Swallow it as a full. don't chew, crush or break it. Tadalafil may be a phosphodiesterase (PDE-5) inhibitor. In dysfunction, it works by increasing blood flow to the penis by relaxing the muscles in penile blood vessels. In benign prostatic hyperplasia (BPH), it helps relax the muscles within the endocrine gland and therefore the bladder to alleviate urinary symptoms.