The question, What is fibromyalgia? is a complicated one that doctors and patients have been trying for decades to answer. Fibromyalgia is a chronic condition that causes intense pain all over the body, as well as a host of other symptoms. It affects more than 6 million people in the United States. Doctors classify fibromyalgia as a syndrome, which means it has a group of signs, symptoms and characteristics that occur together.
Medical Definition of Agonist. Agonist: A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology. Last Editorial Review: 5/13/2016.
A drug that is an agonist attaches itself to receptors in the brain, and then produces a chemical reaction. For example, heroin is an opioid agonist. It binds to opioid receptors that control pleasure and pain, the result being a feeling of euphoria and well being.Other examples of opioid agonists, sometimes referred to as âfull agonists,â are oxycodone, morphine and opium.or example, heroin is an opioid agonist. It binds to opioid receptors that control pleasure and pain, the result being a feeling of euphoria and well being. Other examples of opioid agonists, sometimes referred to as âfull agonists,â are oxycodone, morphine and opium.