Central nervous system, drugs acting opioids

Katzung PHARMACOLOGY, 9e > Section V. Drugs That Act in the Central Nervous System > Chapter 31. Opioid Analgesics Antagonists > ... 

Analgesics are divided into two groups opioids (morphine-like substances), which predominantly influence the central nervous system (CNS) and nonopioids (nonsteroidal antiinflammatory or fever-reducing drugs—NSAID), which act predominantly on the peripheral nervous system. 

Opioids are compounds that bind one or more of the many different opioid receptors in the body. Opioids act primarily on the central nervous system. The selectivity of a given opioid for the various opioid receptors determines its characteristic activity. While many opioids are powerful analgesics, opioids often cause physical dependence and have tolerance issues. Sedation and decreased rate of breathing are also side effects associated with opioids. Despite their problems, opioids are generally the drug of choice for treating severe, acute pain. 

Drugs and chemicals are known to cause activated interaction. The depressant action of opioid drugs is enhanced by drugs acting on the central nervous system (CNS) such as alcohol, anesthetics, anxiolytics, hypnotics, tricyclic antidepressants, and antipsychotics. Concomitant administration of opioid analgesics and monoamine oxidase inhibitors (MAOIs) should be avoided, or extra care should be taken if such a therapy is inevitable. Fatal reactions are reported when treated along with selegiline. Interactions also are reported with cyclizine, cimetidine, mexiletine, cisapride, metoclopramide, or domperidone. 

Like Rohypnol, GHB is a central nervous system (CNS) depressant, which, when tested on animals, induces a sleep-like state in doses ranging from 0.1 to 1.5 milligrams per kilogram.33 Although many neurotransmitter systems are affected by treatment with GHB, evidence supports the hypothesis that GHB itself acts as a neurotransmitter. This implies that GHB is a naturally occurring chemical in the body that is necessary for normal nervous system functions. Administered as a drug, GHB has been shown to temporarily inhibit the release of dopamine in the brain.34 This inhibition is followed by a marked increase in the release of both dopamine and naturally occurring opioids, such as endorphins.35... 

Current antitussives are broadly divided according to their site of action as either central or peripheral, although many act to some extent at both locations. Centrally acting antitussives act within the central nervous system (CNS) to suppress central cough pathways and comprise the majority of currently used drugs. However, opioids, which are gold standard antitussive agents, suffer from numerous... 

Opiates are drugs naturally found in the opium Poppy Papaver Sonnfferum, and opioids are semi-synthetic drugs prepared from the natural opiates. Both act on the central nervous system producing cough suppression, analgesia, euphoria, sedation, respiratory depression and arrest, nausea, confusion, unconsciousness, coma, and addiction. In 2007, the number of opioid users in Europe was estimated between 1.2 and 1.5 million people (2). 

Opioid drugs act at opioid receptors distributed throughout the central/peripheral nervous system, causing a wide range of physiological, behavioural and cognitive effects. The main adverse drug interactions are due to additive depressive effects on the CNS, which results in loss of consciousness, respiratory depression and hypotension. 

---