Pharm Quiz 3 Flashcards
Etomidate MOA
Potentiation of GABAa mediated Chloride shift
Etomidate- What is the limiting factor affecting use?
Transient depression of adrenocortical function
What would depression of the adrenocortical function do?
Adrenal glands on top of kidneys will release hormones in response to stress, so when you block or inhibit that, the body cannot respond to normal stressful situations.
Can have fatal complications from this because it suppresses the CV and Resp effects of the adrenal glands.
Pt in sepsis, this can be very dangerous because they need their adrenal glands to support them and create stress responses.
CNS effects of Etomidate
Decreased CBF.
Decreased CMRO2.
Decreased ICP, while maintaining CPP.
Decrease IOP.
CV effects of etomidate
Provides CV stability and is drug of choice for unstable cardiac system.
Minimal change in HR, BP, CVP.
Careful in pt with aortic or mitral valve disease.
Respiratory effects of Etomidate
Dose dependent decrease in MV,.
Compensatory increase in RR.
Decreased chemoreceptors.
May have brief period of apnea, followed by hyperventilation.
Does etomidate cause histamine release?
No histamine release. This is tied to the CV stability because histamine release would cause vasodilation/decrease in vascular tone.
Unique qualities of etomidate
Increase incidence of PONV.
No analgesic properties.
Low incidence of allergic reaction.
Involuntary myoclonic movement is common.
Chemical Structure of Etomidate
Has 5 sided Imadazole ring which is stable in big pH changes.
Only IV induction drug that is not a racemic mixture.
2 Isomers, but R isomer is hypnotic.
Pharmacokinetics of Etomidate
Rapid distribution half-life.
76% plasma protein binding.
Total body clearance is rapid.
Less accumulation compared to a lot of other induction drugs- useful for repeat doses and continuous infusions.
Etomidate onset/peal/duration
Rapid onset 30-sec.
Peak 1 min.
Duration 6-8min
Dexmedetomidine MOA
Highly selective Alpha2-Adrenergic Agonist.
Negative feedback loop.
Normally when Alpha 2 picks up Norepi, it sends a signal saying “we have enough epi/NE”, so secretion of these stops. Precedex acts as a false neurotransmitter and tricks the system into thinking it does not need any more secretion of NE/Epi.
What is the active component in dexmedetomidine?
D-Isomer of medetomidine.
How is dexmedetomidine metabolized?
By hepatic microsmal enzymes
How is dexmedetomidine more selective than clonidine?
1600:1 Alpha2:Alpha1.
Versus clonidine being 220:1
Dexmedetomidine has three sites of action. What are they?
Brain (locus ceruleus).
Spinal cord.
Autonomic Nerves.
CNS effects of dexmedetomidine
Decrease CBF.
No change in ICP or CMRO2.
Decrease MAC requirement for inhaled anesthetics.
Decrease plasma catecholamine concentration.
CV effects of Dexmedetomidine
Moderate decrease in HR.
Moderate decrease in SVR.
Bolus may cause more pronounced bradycardia (and rebound hypertension).
Respiratory effects of Dexmedetomidine
Small decrease in TV, but no significant change in respiratory rate.
Chemoreceptors remain intact.
Synergistic effects with other sedative/hypnotics.
JAMA Pediatrics Swedish Analysis
Single exposure to anesthetic drugs:
0.41% lower school grades.
0.97% lower IQ.
Summary: Children were NOT FOUND to be at increased risk of adverse child development outcomes compared with their biological sibling who did not have sugery/anesthetic.
MASK trial summary
Anesthesia exposure before age 3 was not associated with deficits in the primary outcome of general intelligence.
Multiple exposures may be linked to changed in behavioral and learning difficulties.
What does the FDA say about anesthetics?
Children <3yo and pregnant women in 3rd trimester= BLACK warning label; however, Am Coll of OB/GYN disagrees.
Describe the sleep associated with the administration of Precedex
Precedex is a more natural and restful sleep compared to other drugs because it puts the body into a more natural state of rest and digest.
What is Nociceptive pain
Pain you feel because something happens to your body structure. Usually referred to as sharp, stabbing.
What is Neuropathic pain
Pain you feel, but nothing actually happen to your body.
Sometimes referred to as burning, or lightning bolt (shooting).
Four “Phases” of nociceptive pain.
- Stimulation.
- Transmission.
- Perception.
- Modulation
What happens during stimulation of nociceptors.
Noxious stimulus of nociceptors releases neural chemicals that also stimulate other nociceptors. (bradykinin, histamine, prostaglandins, leukotrienes, serotonin, substance P, Potassium.)
What happens during transmission of nociceptor’s response?
Action potential moves from site of stimulus to the dorsal horn of the spinal cord, then to the CNS.
From dorsal horn, neurotransmitters are released: Glutamate, Substance P, Calcitonin Related Peptide.
What helps us differentiate between types of pain?
Several pathways at the dorsal horn.
A delta and C.
A-Delta pathway detects what type of pain.
A-Delta is large diameter and sparsely myelinated: Sharp Localized pain.
C Pathway detects what type of pain?
Small diameter/unmyelinated: Dull, aching pain.
Which neurotransmitter has been targeted for migraine medications?
Calcitonin Related Peptide.
What happens during perception of nociceptive pain?
Conscious experience of pain.
- Pain impulse relayed through thalamus.
- Higher cortical structures transmit pain.
What happens during modulation of nociceptive pain?
Inhibition of impulses via the brain stem.
Releases endogenous opiods, serotonin, Norepinephrine, GABA.
Why do we not feel pain from a serious injury right away?
When we release Dopamine from painful stimuli, it briefly will stop you from truly feeling the pain. It naturally allows you some time to assess the situation and then react, before you actually feel the pain.
What are some causes of neuropathic pain?
Sustained by abnormal processing of sensory input;
Nerve damage, persistent stimulation, autonomic dysfunction.
What is allodynia?
Sensation of pain from a normally non-painful stimulus.
What is defined as chronic pain?
Chronic pain is >3 months
or
pain past the time of normal tissue healing.
Which age group has highest prevalence of opiate addition/overdose death?
Age 45-64yo.