It is also sometimes called erythrocytosis, which means too many red blood cells. And it used to be called polycythaemia rubra vera or PCRV. PV is a type of rare blood disorder called a myeloproliferative neoplasm.These are conditions that cause an increase in the number of blood cells.t is also sometimes called erythrocytosis, which means too many red blood cells. And it used to be called polycythaemia rubra vera or PCRV. PV is a type of rare blood disorder called a myeloproliferative neoplasm.
Acetaminophen -- best known as Tylenol in the United States -- does not appear to help ease lower back pain and offers little relief for the most common form of arthritis, according to a new report.
OTC Pain Relief: Understanding Acetaminophen. Youâve probably taken acetaminophen at one time or another for fever or pain relief. You may know acetaminophen as the active ingredient in Tylenol and many other over-the-counter (OTC) products, including cold medications. When used as directed, taking acetaminophen is generally safe and effective. But it can be harmful if itâs not taken correctly.