Opioid Analgesics Flashcards
Typical Pharmacologic Approaches to Chronic Pain (4)
Opioid Analgesics
NSAID’s
Glucocorticoids
DMARD’s
Prototype opioid agent
Morphine
Opioids are used to produce what effects? (5)
euphoria analgesia sedation relief from diarrhea cough suppression
Opium
greek word meaning juice –> exudate from poppy seeds containing 20 biologically active components including morphine and codeine
opiates
drug extracted from poppy exudate
morphine and codeine
Opioid
natural or synthetic drug that binds to OPIOID RECEPTORS to produce AGONIST EFFECTS
Narcotic
pharmacological compounds used to treat moderate to severe pain
Natural Opioids occur as (5)
morphine
codeine
endogenous –> endorphins, enkephalins, dynorphins
Three Major Endogenous Opioid Receptors
Analgesic properties associated primarily with?
Mu –> 1 and 2 - analgesic responses
Kappa
Delta
Pharmacokinetics for all opioids
absorption - well absorbed from GI - experience 1st pass effect
metabolism - Hepatic glucuronidation primarily
Latency to onset decreases from transdermal to pulmonary inhalation
Morphine metabolism important notes
Morphine converted to M6G and M3G
M6G has significant analgesic properties
Mechanisms of Analgesia (3)
Gi/Go coupling
Inhibits adenylyl cyclase - decreased cAMP
Reduces intracellular Ca - leads to Decreased neurotransmitter release
Increase post-synaptic K channel opening - hyperpolarization
Mechanisms of Analgesia with Ascending Pain Pathways (3)
Inhibition of AFFERENT PAIN TRANSMISSION
Decreases EXCITABILITY OF PERIPHERAL SENSORY NEURONS
Blocks pain signaling both pre-synaptically and post-synaptically in DORSAL HORN
Mechanism of Analgesia with Descending Pain pathways
BLOCKS INHIBITORY GABA INTERNEURONS
leads to ENHANCED INHIBITION OF NOCICEPTIVE PROCESSING
3 Sites of Action of Opioids in Descending Pain Pathways
Periaqueductal Gray Area
Rostral ventral medulla
Locus coeruleus
Analgesia affects both _____ and _____ aspects of pain
sensory
affective
Opioids affect breathing how?
What clinical scenario should the be used with caution?
why?
cause respiratory depression
head trauma
reflexive cerebral vasodilation
Pupils with opioids
pin-point (constricted)
GI effects with opioids
constipation
Opioid effects on _____ release can lead to urticaria, itching, diaphoresis, and vasodilation
HISTAMINE
Drug Interactions of Opioids
CNS Depressants MES Inducers MAOI's Mixed agonist-antagonists Antagonists
What is the major drug that negatively interacts with MAOI?
MEPERIDINE
hyperpyrexic reaction
Strong Agonists (8)
Morphine Hydromorphone Oxymorphone Methadone Meperidine Fentanyl Sufentanil Heroin
Moderate Agonists (3)
Codeine
Oxycodone
Hydrocodone
Mixed Agonist/Antagonist (4)
Buprenorphine
Butorphanol
Nalbuphine
Pentazocine
Other Opioid Agonists
Dextromethorphan
Diphenoxylate
Loperamide
Tramadol
Opioid Antagonists
Naloxone
Naltrexone
Nalmefene
treatment of OVERDOSE
Which Mixed Agonists/Antagonists activate kappa and block mu? (3)
Butorphanol
Nalbuphine
Pentazocine
Hydromorphone vs morphine
7 to 10x more potent
Fentanyl notes
TRANSDERMAL PATCH available
72 hours release
80x more potent than morpheine
Codeine (3 important notes)
less euphoria
lower abuse potential
can produce significant sedation
Naloxone
REVERSES ACUTE OPIOID OVERDOSE
can produce reversal of CNS and respiratory depression WITHIN 30 SECONDS
Naltrexone vs Naloxone
takes longer to take effect but LASTS LONGER
maintenance drug of opioid addiction
Withdrawal symptoms can occur within?
usually subside within?
6 to 10 hours
5 days
Methadone
primary intervention to treat opioid addiction
MILDER WITHDRAWAL SYMPTOMS
