Some illegal “street” drugs called “poppers” such as amyl nitrate, butyl nitrate, or nitrite also contain nitrates. Missed Dose If you miss a dose of this medicine, take it as soon as possible. If you are a Mayo Clinic patient, this could include protected health information. Taking too much tadalafil can raise your chance of experiencing side effects , including: Headache. Of course, the dosage is decided by your doctor. One of the first questions most men ask is about how much tadalafil to take.Tadalafil under the name of Cialis is used to treat erectile dysfunction (impotence) and symptoms of benign prostatic hypertrophy (enlarged prostate). Another brand of tadalafil is Adcirca, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women. At Blue Sky Peptide, we offer competitive prices on an extensive range of peptides and research liquids for sale to meet your budget. Order now. It is the brand name for tadalafil, a medication also used to treat ED. Tadalafil is in a class of drugs called phosphodiesterase-5 (PDE5) inhibitors and is available in a generic form often.