Opiate Analgesics Flashcards
What kind of disease is delayed by analgesics?
RA
What are the four types of analgesics?
- opioids
- NSAIDs
- Glucocorticoids
- DMARDS
Where do analgesics work?
Dorsal horn afferent neurons synapse
At site of pain/inflammation
Promoting pain repression signal
What is the prototypical opioid analgesic?
Morphine
What are opioids used for, besides analgesia?
Euphoria
Relief from diarrhea
Cough suppression
What is opium?
Greek word meaning “juice” from the poppy seed
What is opiate?
Drug extracted from the exudate of the poppy
What is an opioid?
Natural or synthetic drugs that binds to the opioid receptors producing an agonist effect
What is a narcotic?
Term used to characterize pharmacological compounds used to treat moderate to severe pain
What is narcosis?
Stuporous or somnolent state
What are the two naturally occurring opioids?
Morphine and codeine
How does the potency or codeine compare to morphine?
6-7x less
How does the potency of morphine compare to heroin?
Heroin is 2x more potent than morphine
What are the endogenous opioids?
Endorphins
Enkephalins
Dynorphins
What are the two major endogenous opioid receptors?
Mu1
Mu2
Where are Mu1 opioid receptors located? What is their purpose?
Outside the spinal cord
Responsible for central interpretation of pain
Where are Mu2 receptors located? What is their purpose?
Located throughout the CNS
Responsible for supraspinal and spinal analgesia
What are kappa opioid receptors?
Modest supraspinal and spinal analgesia
What are delta opioid receptors?
Modest supraspinal and spinal analgesia
How well are opioids absorbed from the GI tract?
Well, but high first pass effect
What is the primary hepatic metabolism of morphine?
glucuronidation– morphine-6-glucuronide
What does the liver metabolize heroin and codeine to?
Morphine
What is the G protein that opioid receptors act on? What does this do?
Gi/G0 coupling, causing inhibition of adenylate cyclase, and decreased cAMP production
What is the MOA of opioids? (2)
Gi/Go excitation, causing:
- a loss of intracellular Ca and decrease release of neurotransmitters
- Increase postsynaptic opening of K channels, resulting in hyperpolarization
Where do opioid receptors work?
Inhibition of the afferent pain transmission
What are the peripheral effects of opioid receptors?
Activation of distal ends of primary afferent neurons decreases their activation and excitability
What are the effect of opioids on the dorsal horn of the spinal cord?
Presynaptic: block release of pain modulating neurotransmiting
Postsynaptic: opioids inhibits secondary afferent neurons via increase K channel conductance
What is the role of opioids in the descending pain pathways?
Block the inhibitory GABAergic interneurons, leading to enhance inhibition of nociception
What are the three sites of opioid action on the descending pain pathway?
Periaqueductal gray
Rostral ventral medulla
Locus coeruleus
Opioids provide analgesia in two general ways. What are they?
Reduce sensation and affective aspects of pain
In whom is sedation d/t opioids more frequent?
older folks
What is the COD for opioid OD?
Inhibition of the brainstem respiratory mechanism
What happens when there is a buildup of pCO2 d/t decreased respiration secondary to opioid use?
Reflexive cerebral vasodilation
What are the eye findings of opioid use?
Constriction of pupils
How do opioids reduce cough?
Suppress the cough center of the brain via brain stem chemoreceptor trigger zone
Stimulants cause what eye findings?
Mydriasis
What is the effect of opioids on emesis?
Stimulate the chemoreceptor trigger zone in the emetic area
What is the MOA of opioids as antidiarrheals?
Increasing the tone of the intestinal smooth muscle
What are the renal effects of opioids?
Increased tone of the muscle in the bladder and ureters
What are the effects of opioids on the uterus?
Decrease contractions
What are the cardiovascular effects of opioids?
Hypotension
Bradycardia
Why is histamine release with opioids?
hypersensitivity
How do you stop the n/v d/t opioids?
Switch opioids
Anti-emetics
How do you stop the sedation due to opioids?
Lower dose
Add co-analgesics
How do you stop the constipation associated with opioid use?
Stool softeners,
Opioids stimulate what enzymes in the liver?
MES
What is the interaction between opioids and MAOIs?
Hyperpyrexic reaction, including HTN
Which MAOI is highly associated with opioid interaction?
Meperidine
What is the MOA of morphine?
Prototype mu agonist
What is the MOA of fentanyl?
lipophilic mu agonist
What is the MOA of meperidine?
Active metabolite, is proconvulsant
What opioid is used as an antidepressant?
Codeine
What is dextromethorphan used for?
Cough suppressant
What is diphenoxylate used for?
Antidiarrheal
What is loperamide used for?
Antidiarrheal
What is the MOA of tramadol?
Mu agonist 5Ht/NE uptake inhibitor
What are the pros and cons of mixed opioids agonist-antagonists?
Produce adequate analgesia with less side effects, but enhanced psychotropic effects
What is the potency of hydromorphone compared to morphine?
7-10x more potent
How is fentanyl administered? What is the duration of action? How does its potency compare to morphine?
Transdermal
72 hour transdermal
80x greater than morphine
Why is Codeine okay to use for antitussive?
Produce less euphorie
Lower abuse potential
What are the two opioid antagonists?
Naloxone
Naltrexone
How fast does Naloxone work?
30 seconds if administered IV
What is the use of Naloxone?
treatment of OD
What is the use of Naltrexone?
Maintenance of drug for addicts in treatment programs
What is the physiological basis for tolerance to opioids?
Receptor down-regulation
What is cross tolerance?
Tolerance to one drug will produce tolerance to others
What are the parts of the brain that are a part of the reward pathway? What is the effect of opioids here?
Nucleus accumbens
Central/ventral tegmental areas
Opioids increase activation of dopamineric neurons
What is the main drug used for opioid addiction? MOA?
Methadone
Strong opioid agonist with similar effects to morphine, but less withdrawal symptoms
What are the nose effects of opioid withdrawal?
Runny nose
Hyper or hypothermia with opioid withdrawal?
Hyperthermia
What are the eye findings with opioid withdrawal?
Pupillary dilation
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : morphine
Stronge
Natural
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : codeine
Moderate
Natural
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : oxycodone
Moderate
semi-synthetic
Strong, moderate or mixed (antagonist/agonist): pentazocine
mixed
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : hydromorphone
Strong
Semi-synthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : oxymorphone
Strong
semisynthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : methadone
Strong
Synthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : meperidine
Strong
Synthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : hydrocodone
Moderate
semi-synthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : fentanyl
Strong
Synthetic
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : levorphanol
Strong
Synthetic
Strong, moderate or mixed (antagonist/agonist): tramadol
Moderate
Strong, moderate or mixed (antagonist/agonist)? Natural or synthetic? : propoxyphene
Moderate
Synthetic
Strong, moderate or mixed (antagonist/agonist): nalbuphine
Mixed
Strong, moderate or mixed (antagonist/agonist): buprenorphine
Mixed
Strong, moderate or mixed (antagonist/agonist): butorphanol
mixed
Strong, moderate or mixed (antagonist/agonist)?: nalorphine
Mixed
What is the use of dextromethorphan?
Antitussive
What is the use of diphenoxylate
Antidiarrheal
What is the use of loperamide
Antidiarrheal