CNS Medications Analgesic Drugs
Opiods o 3 classes Meperidine-like drugs Methadone-like drugs Morphine-like drugs o Mechanism of Action Agonist – binds to an opioid pain receptor in the brain and causes an analgesic – response – the reduction of pain sensation. Agonist-Antagonist - (partial agonist or mixed agonist) binds to a pain receptor and causes a weaker pain response than does a full agonist. Antagonist – binds to a pain receptor but does not reduce pain signals. It functions as a competitive antagonist because it competes with and reverses the effects of agonist and agonist-antagonist drugs at the receptor sites. o Side Effects **Important to Know** – CNS depression (most serious), hypotension, flushing, bradycardia, sedation, disorientation, euphoria, lightheadedness, dysphoria, N & V, constipation, biliary tract spasm, urinary retention, itching, rash, wheal formation, respiratory depression and possible aggravation of asthma. o Contraindications – allergy, head injury, respiratory problems (severe asthma), morbid obesity, sleep apnea, myasthenia gravis, paralytic ileus and pregnancy. o Route/s of Administration – P.O., IV, IM, SC o Common Drugs codeine sulfate meperidine HCl (Demerol) methadone HCl (Dolophine) morphine sulfate propoxyphene HCl hydromorphone oxycodone Page 1 of 25