Week 10- Opioid Analgesics Flashcards
Purpose for opioid analgesics
To relieve moderate-to-severe pain
True or false: Opioids are controlled substances in the US because of their potential for abuse
True
The term opioid has been instituted to represent all types of ________ analgesic-like agents and _________-like medications, regardless of their origin
Narcotic
Morphine
Opioids can be these types of sources
Natural
Synthetic
Semisynthetic
Opium contains about ____ biologically active compounds, including morphine and codeine
20
The body manufactures and releases these to control pain and inflammation
Endogenous opioid peptides
Three distinct families of endogenous opioid peptides
Endorphins
Enkephalins
Dynorphins
Endogenous opioid peptides can help regulate…
Immune system
GI function
Cardiovascular responses
Physiological systems
True or false: Endogenous opioid peptides are not involved in many aspects of behavior, including response to physical and psychological stress, eating and drinking behaviors, and physiological addiction to exogenous opioids and other drugs
False
(it does)
Opioid receptors
Mu
Kappa
Delta
Classification of special agents
Strong agonists
Mild-to-moderate agonists
Mixed agonist-antagonists
Antagonists
This classification of special agents treat severe pain and have a high affinity with mu receptors
Strong agonists
Examples of agonist drugs
-Hydromorphone (Hydrostat, Dilaudid)
-Meperidine (Demerol)
-Methadone (Dolophine, Methadose)
-Morphine (MS Contin, Roxanol, Statex, others)
-Tramadol (Ralivia, Ultram)
-Fentanyl
This classification of special agents treat moderate pain
Mild-to-moderate agonists
Examples of mild-to-moderate agonists
-Codeine
-Hydrocodone (Hycodan)
-Oxycodone (OxyContin, Roxicodone)
-Propoxyphene (Darvon)
This classification of special agents exhibit some agonist and antagonist-like activity at the same time
Mixed agonist-antagonists
True or false: Mixed agonist-antagonists leads to less risk of side effects associated with mu receptors
True
True or false: Mixed agonist-antagonists produce less psychotropic effects
False
(more)
True or false: The maximal analgesic effect of mixed agonist-antagonists is great as strong mu agonists
False
(may not)
True or false: Antagonists produce analgesia
False
(they do)
This classification of special agents is primarily used to treat opioid overdoses and addiction
Antagonists
The primary agent currently used in the US to treat opioid overdose is ______________
Naloxone
Metabolic inactivation of these drugs takes place primarily in the __________
Liver
Some degree of metabolism also occurs in ________, ________, and ________
Kidneys
Lungs
CNS
Pharmacokinetics of opioids
-Oral, IV, IM, rectal, sub-Q, epidural, intranasal
-Transdermal patches
-Iontophoresis
Mechanism of actions of opioids
Spinal effects
Supraspinal (brain) effects
Peripheral effects
Decrease ascending (afferent) pain transmission, combined with their ability to activate descending (efferent) pathways that reduce pain
Spinal effects
Supraspinal (brain) effects
At peripheral sensory nerve endings, opioids decrease excitability of the neuron and inhibit the neuron from initiating transmission of painful stimuli toward the spinal cord
Peripheral effects
Inhibitory effect is mediated by opioid receptors that are located on both presynaptic and postsynaptic membranes of pain- mediating synapses
Spinal effects
Opioids bind to specific receptors in the midbrain periaqueductal gray matter (PAG) and remove inhibition (disinhibition) of descending pathways that decrease pain
Supraspinal (brain) effects
Increased activity of descending pathways travels through the ventromedial ________ (VMM) to reach the __________ horn of the spinal cord
Medulla
Dorsal
(supraspinal brain effects)
Neurons in descending pathways release _________ and __________ onto dorsal horn synapses and inhibit the ability of these synapses to transmit painful impulses to the brain
Serotonin
Norepinephrine
(supraspinal brain effects)
SLIDE 16
Clinical applications for opioids
-Acute moderate-to-severe pain following surgery, trauma, and myocardial infarction
-Chronic pain such as cancer
(non-opioid drugs should be attempted first)
-Should be used only when necessary, because of the potential for serious side effects
-Not effective in treating sharp and intermittent pain
-Anesthetic pre-medication or as an adjunct in general anesthesia
-Cough suppression (short-term use of codeine and codeine-like agents)
-Control of severe diarrhea
-Acute pulmonary edema
-Patient controlled analgesia (PCA)
True or false: Orally administered opioids are more effective when given at regularly scheduled intervals rather than when the patient feels the need for them
True
Problems and adverse effects of opioids
-Metal slowing and drowsiness (sedative properties)
-Respiratory depression (slow the breathing rate)
-Orthostatic hypotension
-GI distress
This occurs when an individual repeatedly ingests certain substances for mood-altering and pleasurable experiences, such as the heroin
Addiction
The need to progressively (periodically) increase the dosage of a drug to achieve a therapeutic effect (to provide adequate relief) when the drug is used for prolonged periods
Tolerance
Mechanisms of tolerance
-Receptor down-regulation (removed by endocytosis) and desensitization
-Loss of communication between the opioid receptor and the G protein
Tolerance begins after the ________ dose of the narcotic, but the need for increased amounts of the drug usually becomes obvious after ________ weeks of administration
First
2-3
Tolerance seems to last approximately _____ weeks after the drug is removed
1-2
The onset of withdrawal symptoms when the drug is abruptly removed
Physical dependence
Withdrawal symptoms become evident within ______ hours after the last dose of the drug, and peak on day ____ or day ____ after the drug has been stopped; last about ____ days
6-10
2
3
5
The risk of addiction, tolerance, and dependence is actually very _______ when opioid drugs are used appropriately to treat chronic pain in patients who do not have a history of substance abuse
Low
True or false: Patients never fail to respond to opioids and never report increased pain sensitivity
False
True or false: Pain may worsen when opioid drugs are reaching peak effects
True
True or false: Pain may increase when drug effects are minimal or the dosage is reduced
False
(reduce)
True or false: Careful baseline pain measurements will be needed to see if pain increases when the opioid drug begins to take effect
True
Goal of pharmacological treatment of opioid addiction
To eventually wean the patient from all opioid drugs (inappropriate or illegal use and abuse of narcotics such as heroin
This drug offers several advantages such as milder withdrawal symptoms
Methadone
This drug is a mixed agonist-antagonist that can be used as an alternative
Buprenorphine
True or false: Scheduling therapy when drugs reach their peak effects may be advantageous
True
Constipation especially problematic in SCI patients or other conditions that decrease GI motility
GI discomfort
Opioids are often administered along with _________ and _________
Laxatives
GI stimulants
Respiratory response to any rehabilitation exercise may be blunted
Respiratory depression
