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.
Tylenol contains acetaminophen. The maximum daily dose of acetaminophen must not exceed 4000 mg ('daily' means 24 hours). It is not recommended to take more than 1000 mg of acetaminophen at a time. The interval between 1000 mg doses should be about 6 hours. 500 mg doses can be taken more frequently, e.g. every four hours. Each Tylenol 500 gelcap, etc, contains 500 mg of pure acetaminophen.