Once-a-day use with 5 mg dosing or less may be considered for some people with mild-to-moderate kidney problems. Heart conditions: Speak to your doctor before taking any medication for erectile dysfunction if you: have or have had heart disease have had a heart attack have had a stroke have angina chest pain as a result of poor blood flow to the heart muscle have experienced chest pain during sexual activity have uncontrolled irregular heart rhythm have very Low Blood Pressure have uncontrolled high blood pressure If you experience chest pains, dizziness, or nausea during sex, stop the exertion, and inform your doctor as soon as you can. Tell your doctor if you have any of the following conditions, as they may increase your risk of a prolonged erection: sickle cell Anemia, Multiple Myeloma, or Leukemia. If use of a nitrate-containing medication is considered medically necessary, 48 hours must pass after the last dose of Cialis Tadalafil before taking a nitrate, and only under close medical supervision. While in some cases the condition may improve over time, it can be permanent in other cases. Do not drink grapefruit juice when taking Cialis Tadalafil.The guidance document, Determining Prescription Status for Human and Veterinary Drugs, explains the broad principles and factors that Health Canada considers when deciding whether a drug would be best sold as a prescription drug or a non-prescription product. Cialis; Share Twitter Share Twitter Facebook Share this page on Facebook. Prescription Drugs. Search or browse for information on Prescription Drugs. Enter prescription . Tadalafil belongs to a group of medications called phosphodiesterase type 5 inhibitors. It is used to treat erectile dysfunction (male impotence). It helps to achieve and maintain an .