APEX Flashcards
(120 cards)
What is transmission
afferent pain signal travels from the peripheral nervous system to the central nervous system via a 3 - neuron pathway
During modulation, when is pain inhibited?
Spinal neurons release GABA and glycine (inhibitor NT) & the descending pain pathway release NE, serotonin, and endorphins
When stimulating an opioid receptor, what happens?
reduces NT release from presynaptic neurons and hyperpolarizes post synaptic neurons
what are the four types of opioid receptors (all are G proteins)
Mu (MOP), Delta (DOP), Kappa (KOP), ORL1 (NOP)
how does opioids produce respiratory depression?
by shifting the CO2 response curve to the right
How do opioids effect a healthy patients blood pressure?
although they reduce heart rate, opioids have a minimal effect on blood pressure in healthy patients
Define Dependence
occurs when a person taking a drug will go through withdrawal upon discontinuation of that drug
Define tolerance
occurs when a patient requires higher doses of a drug to achieve a given effect
define addiction
a disease; if a person cannot stop using a drug despite negative consequences from suing that drug, they have an addicition (substance abuse disorder)
except remifentanil, how are all opioids metabolized
hepatic biotransformation
what has to have if an opioid produces an active metabolite
may require a dose adjustment in a patient with an impaired clearance mechanism (kidney or liver failure)
Meperidine MOA
mu and kappa receptor agonist
what is meperidines active metabolite
normeperidine - by CYP450 - causes myoclonus, reduces seizure threshold, and increases CNS excitability. avoid in dialysis patients and use with caution in the elderly
when does alfentanil have such a fast onset
due to being 90% non-ionized - diffuses quickly across the patients blood-brain barrier
why is alfentanil useful in anesthesia
blunting the hemodynamic response to short, intense periods of stimulation, such as tracheal intubation or retrobulbar block
how is remifentanil metabolized
RBC and tissues esterases
following discontinuation of remifentanil, what should be of concerned
hyperalgesia
when is methadone useful
chronic treatment of opioid abuse, chronic pain syndromes, cancer patients
how does methadone decrease pain
Mu receptor agonist, NMDA receptor antagonist, and inhibits reuptake of monoamines in the synaptic cleft
when giving methadone, what ECG changes should we watch for
prolonged QT interval
what can rapid IV administration of opioid cause
skeletal muscle rigidity
if chest wall rigidity occurs, where is the greatest resistance to ventilation
larynx
why use partial agonist opioids
produce analgesia with a reduced risk of respiratory depression
when redosing what is one thing you should consider
there is a ceiling effect, beyond with additional analgesia is not possible