Opioid+Analgesics+and+Anatagonists

===**Use this site to develop the concepts surrounding opioid analgesics and antagonists drugs and their mechanism of action. Opioid Analgesics and Antagonist -Can be classified by chemical structure or receptor action - Mechanism: Binds to a receptor in both the CNS and spinal cord, produces altered precption of pain  - Mechanism of action can be complete agonist, partial agonist, agonist-antagonist, or antagonist  - Afinity receptors are mu, kappa, & delta. - Pharmcokinetics: ADME A- Absorbtion, well orally through mucous membranes ( nasal spray, dermal patch)  D- Distribution, first pass, reduces bioavailability  M- Metabloism,Conjunction with glucuronic acid in the liver  E- Excretion, Metabolized opioids are excerted by glomerular filtration, unchanged drugs are excreted in the urine   -Pharmacologic Effects: Analgesia, u and k receptors involved Sedation and euphria, k-recports stiulation  Cough supression, depress cough in the medulla  Gastrointestional, increases smoothmuscle tone, treatment of diarrhea  Nausea and emesis, direct chemopreceptors trigger zone in medulla  Constipation, tonic contractions in intestional track  Myesis, pinpoint pupils Urinary retention, increases smooth muscle tone  CNS, simulation: anxiety, restlessness, nervousness  Cardiovasclar, desress vasomotor center, high dosage: postural hypotension, bradycardia, syncope  Histamine release, opioids stimulate release, itching and urtcaria   - Drug interactions: alcohol or sedatives= respiratory depression, Meperidine and MAO  Withdrawl symptoms: Yawning, lacrimation,perspiration, gooseflesh, irritability, nausea, vomiting,tachycardia, tremors, chills.**===