MAGA Exam II) Flashcards
What are the 6 multimodal therapies discussed in lecture?
- Periop Fluid
- Carb loading
- Short-acting Anesthetics
- Opioid Sparing
- Temp. Management
- Cerebral/Neuromuscular monitoring
The emphasis on Multimodal Anesthesia for general anesthesia includes which 2 aspects?
Short-acting anesthetics and opioid sparing
Define non-opioid anesthesia. List some alternatives to treat pain.
PT & OT, Chiropractic care, acupuncture, massage, yoga, weight loss, cold/heat, OTC medications, TENS unit…etc.
What is the pain response pathway? (5)
(this was in the pain pathway slide set too)
What are the 2 classes of opioids?
1) Phenanthrenes (L-isomers have opioid activity; morphine, codeine, thebaine)
2) Benzylisoquinolones (Lack opioid activity; Papaverine, noscapine)
Chart to memorize (per Dr. Castillo)
Using multimodal anesthesia, what 2 meds might we give in preop to better control pain later?
Acetaminophen 1000 mg PO, Gabapentin 300 mg PO
Regarding Gabapentin’s preemptive analgesia, What 3 studies/ procedures is it used in?
- Spine surgeries
- Orthopedic procedures
- Major abdominal procedures.
For Preemptive Gabapentin, what patient population is it contraindicated for?
- MG and Myoclonus patients
- Reduce dose in elderly patients
What is the PO dose of preemptive Gabapentin?
When should we give it?
What is it’s MOA?
300-1200mg PO
1-2 hrs prior to OR
GABA analogue
What is the MOA of gabapentin?
GABA Analog actions:
- Blockage of VG Ca⁺⁺ channels
- inhibits release excitatory neurotransmitters
- Descending inhibitory tract enhancement
Is gabapentin lipid soluble?
What percentage protein-binding occurs with gabapentin?
What’s it’s E 1/2 time?
- Yes; Lipid soluble
- not protein-bound (<3%)
- Brief E 1/2 time
What are Gabapentin’s side effects (7)?
Think ↑GABA effects
- Somnolence
- fatigue
- ataxia
- vertigo
- GI disturbances: constipation
- abrupt withdrawal in seizure pts (when Gaba is used as an antiepiliptic): causing seizures
- wt gain
What are indicated uses for gabapentin?
- Partial seziures in adults and children
- Neuropathic pain (DM Neuropathy, Neuralgias, Fibromyalgia, Phantom Limb)
- Chronic pain syndromes.
Does gabapentin have any drug-drug interactions?
No drug interactions
What are the 7 effects of NSAIDs discussed in lecture?
- Decrease activation of peripheral nociceptors
- No addictive potential
- Preemptive analgesia
- Absence of ventilatory depression
- Less nausea and vomiting
- Long duration of action
- Absence of cognitive effects
What enzyme catalyzes the synthesis of prostaglandins?
COX (Cyclooxygenase)
This form of COX is responsible for gastric protection, hemostasis, and renal function…
COX-1
COX-1 or COX-2?
Ubiquitous, “physiologic”, inhibition of this enzyme is responsible for many adverse effects.
COX-1
COX-1 or COX-2?
Pathophysiologic, expressed at sites of injury, not protective.
COX-2
COX-2 propagation is responsible for which symptoms?
Pain, inflammation, and fever
What are the three main properties of NSAID drugs?
Analgesic
Anti-inflammatory
Antipyretic
Are the following drugs non-specific or COX-2 selective?
–Ibuprofen, naproxen, aspirin, and ketorolac–
What gastric symptomology would be seen with administration of these drugs?
Non-Specific
Increased gastric irritation with these drugs
Celecoxib (Celebrex), Rofecoxib (Vioxx), Valdecoxib (Extra), Parecoxib (Dynastat) are all examples of what?
COX-2 Selective NSAIDs
Do COX-2 selective NSAIDs affect platelets?
No, COX-1s do.
Because COX-2 selective NSAIDs have no effect on platelets, this would increase the chance of what pathology?
Clotting (think MI and CVA)
COX-2 selective and nonspecific inhibitors have _____________ analgesia
Comparable
What was the first COX-2 inhibitor that decreases PG synthesis?
Celecoxib (Celebrex)
What is the dosage for Celebrex?
200 to 400 mg PO QD
Celebrex reaches its peak in…
3 hours
For Ofirmev, what is the Dose, Peak effect time, and duration?
Dose is 3-4g max daily for testing purposes
What kind of anti-inflammatory properties does Ofirmev have?
Trick question, none (or no significant effects)
What contraindication(s) would you need to consider when prescribing Ofirmev?
Hepatic Impairment
According to the TXWES medication guide, what are the doses for Acetaminophen (Ofirmev), Ketorlac (Toradol), & Ibuprofen (Caldor).
What is the MOA for Ofirmev?
Reduces prostaglandin metabolites
What are absolute contraindications for Ketorolac per Castillo?
Anaphylaxis reaction, Patient in Chronic Renal Failure (Not severe impairment), Low platelet count.
For Ketorolac, what is the:
- MOA
- Peak
- Dosing
MOA: Inhibits PG synthesis by inhibiting COX 1 and COX 2
Peak: 45 to 60 minutes IV
Dose: 15 to 30mg q6h (1/2 dose in elderly)
Max Dose: 60-120mg QD
What are some contraindications to consider when giving Toradol?
- Severe Renal impairment (not absolute C/I but needs to be heavily considered)
- Renal Failure (For sure)
- Risk for bleeding
- CAD
- CABG
- Pregnant
- NSAID allergy
Decrease dose (usually 1/2) for elderly: 15% loss in kidney function per decade after 50)
Ibuprofen:
- MOA
- Contraindications
- Dose
- Peak
- Excretion
- COX 1 & 2 Inhibition = ↓ PG synthesis
- Nephropathy, CABG, bleeding disorders, wound healing and esp. allergy!
- 200 - 800 mg QD
- 1-2 hours
- Urine & Bile
With non-opioid anesthesia, what medications are used for induction?
Propofol, Lidocaine, Ketamine, volatile anesthetics. Paralytic if needed.
A 50 y/o, 60 kg female patient received a Lidocaine initial dose of 1 mg/kg with a subsequent infusion of 1.5 mg/kg/hour for 1.5 hours. How much total Lidocaine in mgs did she receive in the PACU?
60kg x 1 mg/kg = 60 mg
60 kg x 1.5 mg/kg = 90 mg (1 hour)
(60 kg x 1.5mg/kg = 90 mg)/2 = 45 mg (30 minutes)
60+90+45 = 195 mg total!!!
Multidose lidocaine vials are used for _____.
infiltration or peripheral nerve block.
Lidocaine is an ______ structure local anesthetic.
Which drug is an exception to the amide/ester rule?
- Amide (amides anesthetics have 2 “i”s)
- Cocaine. Cocaine is also local amide anesthetic.
How is lidocaine metabolized?
Liver
What is the IV bolus and infusion dose of lidocaine?
When should the infusion be terminated?
- 1 to 2 mg/kg IV bolus over 2-4 min.
- 1 to 2 mg/kg/hr infusion
- Terminated within 12-72 hours.
Lidocaine plasma concentration of ____ causes what?
1-5 mcg/ml = ?
5-10 mcg/ml = ?
1-5 = analgesia
5-10 = circum-oral numbness; tinnitus; skeletal muscle twitching; systemic HYPOtension; myocardial depression
Lidocaine plasma concentration of ____ causes what?
10-15 mcg/ml = ?
15-25 mcg/ml = ?
These are OD levels
10-15 = Sz’s; unconsciousness
15-25 = apnea (pons & medullary depression); coma
If we give Lido w/ Epi, should the dose be higher or lower?
Why?
Higher: epinephrine will locally vasoconstrict and prevent lidocaine leakage into the intravascular space.
(Castrater)
How is lidocaine overdose treated?
Lipid rescue
What is one of magnesium’s primary MOAs (for this pharm class)?
N-methyl-D-aspartate (NMDA) receptor
antagonist
- Probably potentiates opioids centrally
and peripherally
Mg++ regulates which four cellular functions?
- Ca++ access intracellularly.
- Neurotransmission
- Cell signaling
- Enzyme function
Which patients receive magnesium sulfate most often per Castillo?
Preeclamptic & eclamptic OB patients.
This med has anti-nociceptive effects by antagonizing the NMDA receptor and “probably” potentiates opioids centrally and peripherally.
Magnesium
Which ion has limited movement across the BBB?
Mg⁺⁺
What conditions are contraindicative for magnesium administration?
Myasthenia Gravis & Renal Failure
What adverse side effects could occur with Mg++?
Hypotension, bradycardia, ataxia, somnolence, decreased muscular tone.
What is Mg⁺⁺ dosing for the following two situations?
Preop:
Intraop:
- Preop: 50 mg/kg IV
- Intraop: 8 mg/kg/hr IV
Be prepared to treat bradycardia and/or hypotension
What opioid requirement does the use of Mg++ significantly decrease?
Fentanyl
It is thought that Mg++ potentiates opioids both centrally and periphreally
What drug class does Ondansetron fall into?
What was it first developed for?
What CYP450 is relevant to ondansetron?
It is the first 5-HT3 antagonist
-It was approved for CINV
-Responsiveness decreased by variations in the CYP2D6 activity!
Ondansetron is equivocal to what two drugs in its treatment of N/V?
Droperidol & Metoclopramide
What are the side effects of Ondansetron?
- HA
- Constipation
- Possible QT prolongation if given rapidly so give it slowly!!
What is the duration & dose of Ondansetron?
Duration/plasma half life is 4 hours!
Dose: Adults: 4 mg IV (up to 8 mgs)
Dose: Pediatrics: 0.1 mg/kg IV
What is the MOA of Corticosteroids in the treatment of N/V?
Why are Corticosteroids used with 5-HT3 (Ondansetron) & droperidol?
Hint: It was studied in CINV!
- MOA is unknown: It works on glucocorticoid receptors in Nucleus Tractus Solitarius (NTS).
- Corticosteroids potentiate 5 HT3 antagonists and droperidol!
What is the dose for Dexamethasone (Decadron)?
What is the MOA of Dexamethasone (Decadron)?
4 - 10 mg IV
MOA: Anti-inflammatory; inhibition of phospholipase and cytokines and stabilization of cellular membrane.
What is the delay of onset of Dexamethasone (Decadron)? How long does efficacy persist?
Are there any adverse effects of a single dose of Dexamethasone (Decadron)?
What occurs if it is pushed fast?
- Onset: 2 hours. Efficacy: 24 hours.
- Nope (proven safe even in DM population)
- Perineal burning/itching (usually D/T rapid inj)
What is the MOA of Precedex (Dexmeditomidine)?
How does it compare to Clonidine?
- Highly selective (7-10x more than Clonidine), specific (pontine locus coeruleus), potent, and full α2 adrenergic agonist.
- Clonidine is only a partial agonist
- Shorter duration of action vs. Clonidine
Can we reverse Precedex (Dexmedetomidine)?
Yep, Atipamezole antagonizes Precedex so that’s nice.
What are the primary uses for Precedex (Dexmedetomidine)?
- Concious Sedation: Calmness, easily rousable, spontaneous ventilation, amnesia is ** not** assured. Also good in Postop/ICU
- General Anesthesia: Tracheal intubation and allows for decreased perioperative requirements of inhaled anesthetics & opioids.
- TIVA: Depression of ventilation
For Precedex, state the following:
- Half-time
- Metabolism/Excretion
- It is a weak ___ of CYP450
- Can cause ___tension in high doses and ___cardia with rapid infusion (also high doses)
- 2-3hours (Clonidine=6-10)
- Hepatic/Renal
- Inhibitor
- Hypo/Brady
What are the TIVA/GA doses for Precedex?
- Bolus 0.5-1 μg/kg, over 10 mins
- High Dose
Loading dose of 1 μg/kg, then 5-10 μg/kg/hour IV
0.1-1.5 μg/kg/min infusion
What is the sedation dose for Precedex?
How about IV Regional?
- 0.2-0.7 μg/kg/hour IV
- 0.5 μg/kg with lidocaine
What is the neuraxial dose for Precedex?
- Spinal/Intrathecal/SAB: 3 μg (as combo), 5 μg with Fentanyl, or 25 μg (alone)
- Epidural: 2 μg/kg
We really don’t see this in practice according to Dr. Castillo. Just give IV.
Precedex can decrease the need for inhaled anesthetics & opioids by up to ___%
90
