The popular painkiller acetaminophen (also known as paracetamol) may cause rare but serious skin reactions, the Food and Drug Administration (FDA) has warned. The analgesic is one of the most commonly and long-used drugs available, sold under numerous brandnames in the US, including Acephen, Actamin, Feverall, Q-Pap, Tactinal, Tempra, Tylenol, Uniserts and Vitapap...