Propecia is used for: Treating certain types of male pattern hair loss (androgenic alopecia) in men. Propecia is a steroid reductase inhibitor. It works by reducing the amount of the hormone dihydrotestosterone (DHT) in the body. This may block certain types of hair loss in men. Do NOT use Propecia if: * you are allergic to any ingredient in Propecia * you are pregnant or may become pregnant Contact your doctor or health care provider right away if any of these apply to you. Before using Propecia : Some medical conditions may interact with Propecia . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you: * if you are planning to become pregnant or are breast-feeding * if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement * if you have allergies to medicines, foods, or other substances * if you have a narrowing or blockage in the urinary tract, prostate cancer, or trouble urinating * if you have a history of abnormal liver function tests or liver problems Some MEDICINES MAY INTERACT with Propecia . However, no specific interactions with Propecia are known at this time. Ask your health care provider if Propecia may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine. How to use Propecia : Use Propecia as directed by your doctor. Check the label on the medicine for exact dosing instructions. * An extra patient leaflet is available with Propecia . Talk to your pharmacist if you have questions about this information * Take Propecia by mouth with or without food. * Continue to take Propecia even if you notice improvement of your symptoms. Do not miss any doses. * Taking Propecia at the same time each day will help your remember to take it. * If you miss a dose of Propecia , skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. Ask your health care provider any questions you may have about how to use Propecia .