Exam 1 Opioids Flashcards
What are the endogenous opioid peptides and their cause
- enkephalin: analgesia
- Beta endorpin: runners high
- Dynorphin: hyperalgesia
Receptors: Mu, Kappa, Delta, their effect and their MOA
Mu: analgesia, euphoria, sedation, SE
K: euphoria or dysphoria
Delta: dysphoria
- all R coupled to Gi
- all close voltage gated Ca channels on PREsynaptic nerve terminals (decrease NT release, decreasing pain signaling)
- Mu often K channels on Postsynaptic neuron causing hyperpolarization, inhibiting n transmission and pain signal
- alpha2 receptors also decrease pain transmission in this region
How do opioids influence pain transmission
a. directly at inflammed and damaged tissue
b. inhibition of release of excitatory NT in dorsal horn aka SPINAL ANESTHESIA
c. Thalamic action
How do opioids modulate pain?
d. Periaqueductal gray may release endogenous opioids
e. Rostral ventral medulla
* NE path from LOCUS COERULEAS to dorsal horn may decrease pain
* inhibition of inhibitory neurons (GABA) may increase activity of pathways that inhibit pain (decreases pain transmission in dorsal horn)
Analgesic effect of opioid?
decrease sensation of and reaction to pain
TOLERANCE dev to analgesia
Sedation/mental clouding effect of opioids?
Not sleep aid disrupt REM Morphine --> CNS depression in OD Codeine and meperidine may cause excitement in OD *tolerance dev
Euphoria or dysphoria effect of opioids
Sense of floating, pleasure
- depends on receptor distribution in diff individuals
- tolerance develops to euphoria
Emesis effect of Opioid
N/V in some bc opioids stim chemoreceptor trigger zone in the brain (CTZ)
Will dev tolerance to N/V
*helps to take with food
Depression of cough reflex (antitussive) in opioids
Lower dose than those for analgesia
CODEINE and DEXTROmethorphan
- dextromethorphan not an analgesic
- meperidine doesn’t suppress cough
Tolerance develops to?… not to?
analgesia, sedation, euphoria, N/V, resp depression
NOT to miosis, constipation, seizures
Respiratory depression and opioid
more common in OD, but also with therapeutic; dose dependent
Decreases response of brain stem to CO2
USEFUL IN PULMONARY EDEMA
not good for people with pulm dz (COPD, asthma etc)
May cause bronchoconstriction
Tolerance may dev to resp depression
Elevated ICP and Opioids
Increased CO2 causes vasodilation, increase cerebral blood flow and pressure
*caution giving morphine/opioids to pt with head trauma
Decrease in body temp and opioids
opioids cause dysregulation in hypothalamus
Miosis and opioids
Common in OD but may convert to dilation in comatose pt
- no tolerance develops
- miosis (PNS) blocked by atrophine (anticholinergic)
- no mioisis with meperidine
Truncal rigidity and opioids
think fentanyl (highly lipid soluble)
- supraspinal effect increases tone of large trunk muscles, may interfere with resp or ventilation attempts
- USE NEUROMUSCULAR BLOCKERS to prevent truncal rigidity
Cardiovascular effect of opioids
May cause bradycardia
- hypoTN common (release histamine)
- may result from CNS vasomotor depression or vasodilation from histamine
*Tachycardia with Meperidine (anticholinergic property)
GI effects of opioids
decreased gastric activity local and CNS CONSTIPATION decreased motility Biliary colic, constriction of sphincter of Oddi, decreased secretions *prepare pt and be proactive