Opium alkaloids, derived from crude Papaver somniferum L. plant, are potent analgesic drugs, but their use is limited because of dependence and withdrawal. Opium alkaloids activate the mesocorticolimbic dopaminergic system, which project from the ventral tegmental area to the nucleus accumbens and medial prefrontal cortex, and dopamine is critically important in opioid consumption and sustaining. The reward effect resulting from the activation of the dopaminergic system leads to continued opioid consumption and occurs opioid dependence. After the development of opioid dependence, consumption continues to avoid withdrawal syndrome. Opioid dependence is accompanied with tolerance, which requires the use of high doses to achieve the same effect. When tolerance develops, the chronic consumer continues to use opioid above known toxic doses to produce the same effect, which can result in death regardless of the type of opioid used. Raw Papaver somniferum L. has five high-density main opium alkaloids including morphine, noscapine, codeine, thebaine, and papaverine. Some of these alkaloids bind to classical opioid receptors to produce an opioid-like effect, while the other part mediates non-opioid effects. This chapter reviews the opiod history, receptors, mechanism of action, dependence, withdrawal. In addition, general information about five main opium alkaloids, their effects, uses, routes of administration, pharmacokinetics, adverse reactions, contraindications; effects on reproduction, pregnancy, and lactation were compiled.
According to the 2018 Annual Report of the American Association of Poison Control Centers (AAPCC), published in 2019, the most common cause of poisoning was medicines in all human exposures. According to the data in this report, the most common group of drugs that cause poisoning in humans are analgesics. The first three drugs that cause poisoning among analgesics are fentanyl, acetaminophen, and oxycodone, respectively. Fentanyl and oxycodone are analgesic drugs with an opioid nature. Opioid analgesics are the drugs of choice for acute and chronic pain management, but after repeated exposure, they cause addiction as a result of stimulation in the brain reward center, are used in higher doses to achieve the same effect, and lead to withdrawal syndrome when medication is not taken. Acetaminophen, which takes the second place in analgesic-related poisoning, is a non-opioid analgesic and antipyretic drug. Acetaminophen is often found in hundreds of over-the-counter (OTC) medications. In addition to being an OTC drug, acetaminophen often causes poisoning as it is cheap and easily accessible. This chapter reviews pharmacological properties of fentanyl, acetaminophen, and oxycodone, in addition to poisoning signs and treatments.
Part of the book: Medical Toxicology