Pharmacology pt 3 Flashcards
______ has the shortest DOA of the BDZ
flumazenil
- 0.7-1.3 hrs
- concern for “recrudescence” of sedation from benzos
flumazenil MOA
benzodiazepine antagonist
- partial agonist
Elimination half-life of: Diazepam Midazolam Alprazolam Lorazepam Temazepam Flumazenil
Diazepam: 20-50 hrs Midazolam: 2 hours Alprazolam: 5-25 hours Lorazepam: 10-20 hrs Temazepam: 10 hrs
Flumazenil: 0.7-1.3 hrs
Desflurane degradation in the presence of desiccated carbon dioxide absorbent results in production of _____
carbon monoxide and heat
- desflurane produces most CO
- sevo produces most heat
Order of fluoride production for volatile anesthetics?
- theoretical risk of nephrotoxicity
Methoxyflurane»_space; sevoflurane > isoflurane > desflurane
Compound A is produced from which volatile anesthetic?
Sevoflurane
ED95 dose for: Rocuronium Cisatracurium Vecuronium Pancuronium
Rocuronium: 0.3
Cisatracurium: 0.04
Vecuronium: 0.04
Pancuronium: 0.06
Potency of neuromuscular blockers is best described by their ____
ED95
Effect of dexmedetomidine on BP over time
Biphasic response bc alpha 2 receptors are located in 2 diff places
- initial dose: stimulates peripheral alpha-2 -> Inc in BP, decrease in HR and CO after 3 min
- returns to baseline
- Over the next hour: stimulates central alpha 2 -> reduce sympathetic tone, inc parasympathetic outflow -> slow decline in BP, inc in HR
MOA?
Onset of action ?
Duration of action?
- Cimetidine
- Ranitidine
- Famotidine
H2 receptor antagonist
- raises gastric pH
- Cimetidine (older):
- 1-1.5 hrs
- 3 hours - Ranitidine:
- 1 hrs
- 9-10 hours - Famotidine: 1 hrs
- 1 hr
- 10-12 hours
Which reversal agent is pulmonary edema seen in? (not muscle relaxant)
naloxone
- esp in large doses
CCBs to a naive pt will affect depolarizing and nondepolarizing NMBs how?
Mild augmentation to both
- CCBs prevent Ca2+ from crossing membrane -> less excitation-contraction
*CCBs to chronic users have very little effect
Why is meperidine falling out of favor?
Wide side effect profile and long half-life
*Libby Zion: the reason we have resident work hour limits
How does meperidine decrease shivering?
through the k opioid receptor (not mu)
*although it still affects mu
Major subtypes of opioid receptors
mu, kappa, delta
Actions of:
Mu1 receptor
Mu2 receptor
Mu1 receptor
- analgesia
- physical dependence
Mu2 receptor
- respiratory depression
- miosis
- euphoria
- dec GI motility
- physical dependence
Actions of:
Kappa receptor
delta receptor
Kappa receptor
- analgesia
- dysphoria
- sedation
- miosis
- inhibit ADH
delta receptor
- analgesia
- physical dependence
- antidepressant
Nalbuphine MOA
Kappa agonist
Mu antagonist
What is morphine metabolized to? What is the active metabolite?
M3G and M6G
M6G is active metabolite
What is the only opioid that is also associated with inc in HR?
meperidine
- structurally similar to atropine
Liver blood flow dependent elimination is characteristic of _____ order kinetics
first
What is first order kinetics
drug elimination is proportional to drug concentration
- exponential
What is zero order kinetics?
enzymes involved in drug metabolism are at a max capacity
- drug metabolism is INDEPENDENT of drug [ ] bx enzymes are saturated
- rate of elimination of constant amt of medication is removed over time
- linear
Drugs that follow zero-order kinetics
(- drug metabolism is INDEPENDENT of drug [ ] bx enzymes are saturated
- rate of elimination of constant amt of medication is removed over time)
THE PAW
Theophylline Heparin Ethanol Phenytoin ASA Warfarin
Which induction agent works primarily by blocking glutamate?
Ketamine
- NMDA receptor antagonist
- NMDA r are a class of excitatory glutamate receptor
Which induction agent INDIRECTLY potentiates GABA receptors?
Ketamine
*etomidate, midaz, prop all potentiate via direct action
Succinylcholine effect on:
Upper esophageal sphincter tone
Intragastric pressure
Lower esophageal sphincter tone
Upper esophageal sphincter tone:
- decrease
Intragastric pressure
- increase
Lower esophageal sphincter tone
- increase (greater than intragastric pressure so NO inc risk of aspiration)
How does adding epi to LA work?
Prolongs duration of effect by decreasing local blood flow, LA stays in area of injection.
*does NOT change block onset time
is the active form of LA ionized (charged) or unionized (uncharged)?
ionized
*unionized pass through lipid membrane and reach targets easier than ionized molecules
The onset of action of LA is primarily a result of _____
lipid solubility
- pass thru membrane and reach site of action
pKa
- aka ionization of drug
- lower pKa = more unionized forms = faster onset (pass through lipid membrane and reach targets easier than ionized molecules)
- higher pKa = more ionized forms = slower onset
Addition of what to LA speeds the onset of action?
bicarb - raises the pH of soln -> more unionized fraction -> faster onset (pass through lipid membrane and reach targets easier than ionized molecules)
greater concentration
- ie. chloroprocaine pka 9 would predictably have slow onset, but actually
What is the MOA of ACEi?
catalyzes degradation of bradykinin ->
Arachidonic acid and nitric oxide
Inhibit the vasoconstrictive and sodium retentive properties of ATII (via aldosterone stim)
Promote the vasodilatory and natriuretic properties of bradykinin
____ cleaves angiotensinogen to angiotensin I
_____ then cleaves angiotensin I to angiotensin II
Renin
ACE
*ACEi block this conversion step
_____ release is the final step in the RAS pathway, which is stimulated by ___
Aldosterone
- promotes sodium and water retention in kidney via activation of Na-K pump in distal tubule
ATII
Cyclopentolate MOA and use?
Topical anticholinergic drug to induce mydriasis for ocular procedures
- at risk for anticholinergic toxicity
- dysarthria, tachycardia, psychosis, convulsions, disorientation
Acetylcholine effect on eyes
miosis
- facilitates flow of aqueous humor
- lowers IOP
Echothiophate MOA and use?
Anticholinesterase (inc ACh)
Treats refractory glaucoma by causing MIOSIS
*remember ACh effects on eyes:
miosis
- facilitates flow of aqueous humor
- lowers IOP
Timolol MOA and use
nonselective BB
glaucoma tx
Normally, the rate of rise of FA/FI is related to solubility or the blood:gas coefficient.
What explains why nitrous oxide has more rapid rise of FA/FI than desflurane
concentration effect
- high [ ] anesthetic (ie. 70% nitrous oxide) increases rate of induction
- nitrous oxide is the only gas that can demonstrate [ ] effect
What is the blood:gas coefficient for nitrous oxide and desflurane
Nitrous oxide: 0,47
Desflurane: 0.42
*the blood:gas coefficient is often the most important factor in rise of FA/FI, which is related to the speed of inhalational induction
*the________ is often the most important factor in rise of FA/FI, which is related to the speed of inhalational induction.
In order of most to least, what is the solubility of commonly used inhaled anesthetics
blood:gas coefficient
desflurane > nitrous oxide > sevoflurane > isoflurane
The _______ is a measure of lipophilicity. It is related to anesthetic potency and MAC
Oil:gas coefficient
- higher the coefficient, the lower the MAC
- ie: isoflurane has o:g of 99, and MAC of 1
- desflurane has o:g of 19 and MAC of 6
What are the 4 potassium sparring diuretics?
- Spironolactone
- Triamterene
- Amiloride
- Eplerenone
- block Na reab in collecting tubule, increasing K reab
*The K STAEs
Hyperkalemia sx on EKG other than peaked T waves
- shortened QT interval
- widening QRS
3, PR prolongation
- similar to hypermagnesemia
How much nalbuphine is useful to tx pruritus in neuraxial anesthesia?
5-10mg nalbuphine
What is mannitol?
A sugar alcohol that acts as an osmotic diuretic that is freely filtered at the glomerulus with poor reuptake back into the vasculature
*similar to hyperglycemia
What is Atrial Natriuretic peptide (ANP)?
released in response to atrial stretch (gen d/t volume overload)
- induces diuresis via natriuresis (not osmotic effect)
Prostaglandins affect fluid balance how?
They oppose ADH and RAAS
- facilitates a diuretic and natriuretic effect
- renal afferent arteriolar dilation
Mannitol is an osmotic diuretic, which pt population is it contraindicated in?
CHF - d.t initial increase in intravascular volume
- use furosemide for diuresis in these pts instead
Terbutaline MOA
- causes (hyper/hypo)kalemia
beta2 agonist
- hypokalemia: temp intracellular shift
What is a phase 2 block?
occurs when succinylcholine remains on ACh receptors
- keeps receptors activated and in OPEN position
- occurs after prolonged admin of succinylcholine or single dose > 4mg/kg
Heparin has a 1:1 anti-Xa:IIa ratio.
What does LMWH have?
Increased anti-Xa:IIa ratio.
- shorter chain length does not inactivate thrombin to a significant degree, but it does inactivate Xa
LMWH is cleared (hepatically/renally)
renally,
- Smaller fragments of heparin in LMWH binds to macrophages in liver less -> cleared renally -> leading to longer plasma half lives and effective once daily regimen
Why is LMWH less likely to induce HIT?
smaller fragments of heparin in LMWH binds to platelets less
______ drugs prevent platelet activation and aggregation (clot prophylaxis)
_______ reduce fibrin formation (treatment of acute thrombi)
antiplatelet
Anticoagulant
4 Classes of antiplatelet drugs
- prevent platelet activation and aggregation (clot prophylaxis)
- Irreversible COX inhibitors
- ASA - ADP r inhibitors
- Clopidogrel
- Prasugrel
- Ticlopidine
- Ticagrelor - PDE inhibitors
- Cilostazol
4, G IIb-IIIa inhibitors
- abciximab
- eptifibatide
- tirofiban
5 Classes of anticoagulant drugs
- reduce fibrin formation (treatment of acute thrombi)
- Antithrombin III activators
- Heparin
- LMWH - Heparin like factor Xa inhibitors
- fondaparinux - Direct factor Xa inhibitors
- rivaroxaban
- apixaban - Direct thrombin inhibitors
- bivalrudin
- hirudin
- argatroban
- dabigatran - Vit K antagonist
- Warfarin
Which antiplatelet drug has the longest antiplatelet effect?
Ticlopidine (10-14 days)
- ADP receptor inhibitor
- drug works for several days after admin
- impairs platelets for duration of its lifespan
- needs to be stopped 2 weeks b4 surgery
Which anticoagulant drug has the longest effect?
warfarin/dabigatran
- 2-7 days
Phenytoin and Lidocaine are class Ib antiarrhythmic, that shortens which phase of the cardiac action potential?
Phase 0
- binds to VG sodium channels to terminate ventricular arrhythmias (in the past)
Drugs affecting Cardiac action potential:
- Class 1 (Na channel blocker, Phase 0)
1a: Quinidine, Procainamide
1b: Lidocaine, Phenytoin
1c: Flecainide, Propafenone
Drugs affecting Cardiac action potential:
- Class 4 (Ca2+ channel blocker, Phase 2)
- Verapamil
2. Diltiazem
Drugs affecting Cardiac action potential:
- Class 3 (K+ channel blocker, Phase 3)
- Amiodarone
2. Sotalol
Drugs affecting Cardiac action potential:
- Class 2 (BB, phase 4)
- Propanolol
2. Metoprolol
1a: Quinidine, Procainamide
1b: Lidocaine, Phenytoin
1c: Flecainide, Propafenone
What class blocker are these? What do they block? What phase of the cardiac action potential do they act on?
Class 1 (Na channel blocker, Phase 0 upstroke)
- Verapamil
- Diltiazem
What class blocker are these? What do they block? What phase of the cardiac action potential do they act on?
Class 4 (Ca2+ channel blocker, Phase 2 plateau)
- Amiodarone
- Sotalol
What class blocker are these? What do they block? What phase of the cardiac action potential do they act on?
Class 3 (K+ channel blocker, Phase 3 downstroke)
- Propanolol
- Metoprolol
What class blocker are these? What do they block? What phase of the cardiac action potential do they act on?
Class 2 (BB, phase 4 flat bottom)
Which NMB has the LEAST increase in dosage requirement for burn patients?
Mivacurium
- degraded by pseudocholinesterase (lvls are reduced in burn pts)
Massive burn pts demonstrate resistance to which type of NMBs?
nondepolarizing NMB
Burn pts have MORE ACh receptors
- more receptors mean higher dose of free drug is required to compete with ACh
Most NDMBs need to be increased by how much in burn pts to achieve same intubating conditions as healthy pts?
2-5x
Why shouldnt you used norepi (a1, a2, b1 agonist) intramuscularly?
cause local ischemia and tissue necrosis
Neostigmine effect on the eyes
Acetylcholinesterase inhibitor ->
Increases ACh available at motor end plate -> parasympathetic receptors in eye -> Miosis (pupillary constriction)
*NOT mydriasis
Why is neostigmine (Acetylcholinesterase inhibitor) cotreated with glycopyrrolate?
muscarinic receptor antagonist
Counteracts side effects of neostigmine listed below:
- Cardiac: bradycardia, hypotension
- Pulm: bronchospasm, resp secretions
- GI: peristalsis, inc GI secretions
- Opth: miosis, decreased IOP
Blood:gas partition coefficients of: Desflurane Nitrous oxide Sevoflurane Isoflurane Halothane
Desflurane: 0.42 Nitrous oxide: 0.46 Sevoflurane: 0.69 Isoflurane: 1.46 Halothane: 2.54
*FA/FI will rise faster w/ agents with lower blood:gas partition coefficient (insoluble agents)
How does the gas behave if the Blood:gas partition coefficient is >1? <1?
> 1: more drug is dissolved within blood
- higher solubility
- reduce rate of rise of FA/FI (slow induction)
- ie. isoflurane (1.46), halothane (2.54)
<1: more drug exists in gaseous state than dissolved within blood
- lower solubility
- Inc rate of rise of FA/FI (fast induction)
- ie: Desflurane: 0.42
Nitrous oxide: 0.46
Sevoflurane: 0.69
How do inhaled anesthetics affect spontaneous ventilation?
Minute ventilation will decrease
- increase RR, but decreased TV
- fast shallow breathing
Why is metoclopramide contraindicated in pts with bowel obstruction?
Dopamine antagonist centrally
Cholinergic agonist peripherally
By promoting gastric emptying and increasing gastroesophageal sphincter tone, it decreases risk of pulmonary aspiration
- since it is a promotilitiy agent, you increase risk of bowel perf
Etomidate (GABA agonist) can cause adrenal suppression by inhibiting the enzyme _______, even after a single dose
11-B-hydroxylase
- makes cortisol or aldosterone
Etomidate effect on:
CMRO2
CBF
ICP
decreases all
Anaphylaxis is a type ____ reaction and is ____ mediated
type 1
IgE mediated
Hemolytic anemia is a type ____ reaction and is ____ mediated
Type II
Both IgG and IgM
Contact dermatitis is a type ____ reaction and is ____ mediated
Type IV
T cell mediated
Serum sickness is a type ____ reaction and is ____ mediated
Type III
immune complex mediated
At 1 MAC How does Isoflurane: Affect BP? HR? Minute ventilation? CVP?
BP: Lowers by decreasing SVR
Increases HR
Lower MV (Increases RR, reduces TV)
No change to CVP (too many complex factors at play)
Tx for post op delirium d/t scopalamine?
Physostigmine
- Acetylcholinesterase inhibitor
- > prolongs presence of ACh in the synaptic cleft
- can cross BBB and act as an antidote to antimuscarinic drugs (edrophonium and neostigmine cannot)
*Scope is a muscarinic antagonist (just like glycopyrrolate and atropine)
*Scopolamine is a _______ (just like glycopyrrolate and atropine)
muscarinic antagonist
Drug used to differentiate Myasthenia gravis from Lambert Eaton Myasthenic syndrome (LEMS)?
Edrophonium
- acetylcholinesterase inhibitor
- > prolongs presence of ACh in the synaptic cleft
- reduce muscle weakness in pts with Myasthenia gravis (antibodies destroy ACh receptors)
Physostigmine, Neostigmine, and Edrophonium MOA
- which one crosses the BBB?
- acetylcholinesterase inhibitor
- > prolongs presence of ACh in the synaptic cleft
*physostigmine
Prophylaxis against nerve agent exposure?
Physostigmine
- Acetylcholinesterase inhibitor
- > prolongs presence of ACh in the synaptic cleft
- can cross BBB and act as an antidote to antimuscarinic drugs (edrophonium and neostigmine cannot)
*also used as Tx for post op delirium d/t scopalamine
Tx for gastroparesis. How?
Metoclopramide
- Accelerates gastric emptying
- Reduce gastric fluid volume
- Increased tone and amplitude of gastric contractions
- Enhance peristalsis of duodenum and jejunum
- Accelerates gastric emptying
- NO EFFECT on gastric pH
- Dopamine antagonist at chemoreceptor trigger zone
- Serotonin receptor antagonist at high doses
MOA of Metoclopramide
- Dopamine antagonist at chemoreceptor trigger zone
- Serotonin receptor antagonist at high doses
Why should you avoid metoclopramide in pts with parkinsons disease?
Dopamine antagonist -> increases extrapyramidal symptoms
Codeine is a prodrug that gets converted to what?
- What makes a poor metabolizer and an ultrarapid metabolizer?
Morphine via CYP2D6 ~ 10%
- poor metabolizer: little CYP2D6, little analgesia from codeine
- ultrarapid metabolizer: mult functional copies of CYP2D6 -> converts way more codeine to morphine -> accumulates quickly -> toxicity
Why does Symptomatic hyponatremia decrease MAC?
CNS depression
How does this affect MAC? Acute alcohol use Chronic alcohol use Acute meth/cocaine use Chronic meth/cocaine use
Acute alcohol use: Decrease
Chronic alcohol use: Increase
Acute meth/cocaine use: Increase
Chronic meth/cocaine use: Decrease
How does hypo/hyperthyroidism affect MAC?
It doesn’t
- unless there are alterations in temp
*Hypo/hypercapnia also doesnt
Which metabolic derrangement does NOT affect MAC?
Metabolic alkalosis
*only severe metabolic acidosis affects MAC
How are redheads (melanocortin-1 receptor gene) affected differently to meds?
Have HIGHER MAC requirements
More RESISTANT to lidocaine analgesia
More SENSITIVE to thermal pain
How does Magnesium affect anesthetic requirement?
Volatile anesthetics: INCREASES MAC
TIVA: DECREASES MAC
Why do infants increase volatile anesthetic uptake?
Lower FRC: less “air” to dilute volatile anesthetic
Higher minute ventilation: places more volatile anesthetic in alveoli
MAC requirements peak at ___ age
6 months
Cisatracurium
- Intubating dose
- Elim half life
- Intubating dose: 0.1-0.15 mg/kg
- Elim half life: 25 min via hoffmann elimination
What two things affect the reaction speed / metabolism of cisatracurium?
pH
Temp
*Last longer in pts with high temp and acidosis
Defining feature of alfentanil?
Quick onset and offset of action
- d/t LOW pKa 6.5: primarily non-ionized at physiologic pH (~90%), moves across membranes rapidly -> fast onset and offset
*Generally, w/ opioids, the more lipid-soluble (higher partition coefficient), the faster the onset
Partition coefficient of fentanyl vs morphine? Which one has faster onset?
Fentanyl: 813
Morphine: 1.4
- fentanyl is MUCH faster
- The higher the partition coefficient, the earlier the onset of action
- exception is alfentanil
Which drugs cross membranes faster, ionized or non-ionized drugs?
Non-ionized, low pKa
- ie: alfentanil
Which opioid is the most potent? WHy?
Sufentanil
- high affinity for opioid receptors
(fent and remi are 10x less potent)
Which opioid has the shortest context sensitive half time?
Remifentanyl
- d/t metabolism by nonspecific plasma esterases (red cell esterases)
- just like esmolol
*not affected in pts with pseudocholinesterase deficiency
Rule of “4” for alfentanil
Compared to fentanyl
- 4x faster onset
- 1/4 as potent
- 1/4 shorter DOA
Which drugs cause pain with injection? (5)
- Diazepam
- Etomidate
- Methohexital
- Propofol (bradykinin)
- Rocuronium
Tramadol MOA
synthetic opioid analgesic w/ weak affinity for mu receptor, no affinity for delta or kappa receptors
- PO most common
- peak at 1-2 hours
Also is an SNRI: antinociceptive effect of descending inhibitory pathways of CNS
Why is oral patiromer and sodium zirconium cyclosilicate good agents to use in an anuric pt with hyperkalemia?
oral K binder that elim K through the GI tract after
~ 7 hours for patiromer
~ 1 hour for sodium zirconium cyclosilicate
What happens to PCWP initially after admin of Mannitol?
Increase in plasma volume -> Inc BP and CO -> Inc PCWP
- can cause pulmonary edema in pts with HF
How does mannitol produce diuresis?
Increases osmotic pressure in proximal tubule and LOH ->
Decrease passive reabsorption of water ->
Increase RBF
When mannitol is administered during neurologic and neurosurgical conditions, what is necessary for it to work?
Needs INTACT BBB
- decreases cerebral edema and ICP
- more effective at lowering water brain content than loops or hypertonic saline
The only major contraindication for sugammadex is hypersensitivity to sugammadex, but what situations is it not recommended in?
- Pediatric pts
- Severe RF
- Reversal of anything other than Roc or Vec
- ICU use
Sugammadex is physically incompatible with which drugs, and should not be administered with?
- Zofran
- Ranitidine
- Verapamil
First sx of lidocaine toxicity?
numbness of lips/tongue
THEN visual/auditory disturbances
Max recommended dose of Lidocaine with and without epi?
without epi: 5 mg/kg
with epi: 7 mg/kg
How does renal failure affect the efficacy of NMBDs?
It doesn’t affect the efficacy, but it affects the clearance -> longer DOA
- Don’t need to dose adjust, but need to avoid long acting NMBDs (pancuronium) and intermediate NMBDs (vecuronium)
How is rocuronium eliminated?
70% hepatic
10% renal
- Safe to use in pts with renal failure, with min extended DOA
How is vecuronium eliminated?
Hepatibiliary system
but partially cleared in kidneys
- avoid in pts with RF
Clinically significant effects of plasma cholinesterase (aka pseudocholinesterase aka butyrylcholinesterase), is seen when _____% of the enzyme activity is reduced
> 75%
What is the normal dibucaine number?
Heterozygous atypical? Homozygous atypical?
Normal dibucaine number: 70-80
Heterozygous atypical: 50-60
Homozygous atypical: 20-30
*< 30 suggest prolonged paralysis
30-70 = variable
Chloroprocaine MOA and metabolized how?
Ester LA
Hydrolysis by pseudocholinesterase
Ester vs amide LA name difference?
Ester one “i”
- chloroprocaine
Amides more than 1 “i”.
- lidocaine, bupivacaine
Mivacurium MOA
short acting NDMBs
- Hydrolysis by pseudocholinesterase
*just like chloroprocaine and succinylcholine
Which drugs are metabolized by hydrolysis by pseudocholinesterase / plasmacholinesterase / butyrylcholinesterase?
- Succinylcholine
- Mivacurium
- Ester LA (2-chloro, tetracaine, procaine)
- cocaine
- Heroin
Pts taking ectothiophate eye drops are at risk for what type of reaction with NMBDs?
Sig prolongation of succinylcholine up to 2 weeks after it is d/c
Which muscle is MOST representative of abdominal muscle paralysis (diaphragm) and laryngeal muscle paralysis?
Corrugator supercilli muscle
- moves eyebrows
- MOST resistant to NMBs
- first to recover
Which muscle is MOST SENSITIVE to blockade?
Adductor pollicis muscle
- good for emergence
- recovery of fxn suggest greater recovery of muscles that are more resistant to blockade (diaphragm and laryngeal m)
Recovery to TOF ratio > ___ at the adductor pollicis is recommended prior to extubation
- 9
- or else impairment of laryngeal m and diaphragm
Where is the best place to monitor TOF for extubating conditions?
Adductor pollicis
- more sensitive
Sustained eye opening, handgrip, tongue protrusion correlate with TOF ratio of ____
< 0.7
Head lift, leg lift, tongue depressor, sustained hand grip correlate with TOF ratio of ____
0.7 - 0.9
K-sparing diuretic mneumonic
The K+ STAys with ______
spironolactone, triamterene, amiloride
*Thiazides are assoc w/ hypokalemia
Fenoldopam MOA
selective dopamine 1 agonist
- Increases RBF despite SBP
- NO alpha, beta, DA 2 receptor agonist activity
Does nitroglycerin increase renal perfusion?
no, has selective vasodilatory effects on renal conductance
*Nitro is a veno-arterial dilator
Does adenosine increase renal perfusion?
No, renal vasoconstriction, decrease renal perfusion
*adenosine is a vasodilator
Ketamine effects on on CMRO2 and laryngeal reflexes?
Increase CMRO2
Preserved laryngeal reflexes
Why is nitrous oxide associated with megaloblastic changes and agranulocytosis?
Decreased activity of Vit B12 dependent enzymes, methionine synthetase and thymidylate synthetase
Why is methoxyflurane no longer used?
nephrotoxicity and hepatotoxicity
Does aprepitant have QT prolongation?
Ciprofloxacin?
no
yes - cipro
How does lithium affect NMBs?
How does it affect MAC?
Prolongs both nondepolarizing and depolarizing MR
- reduces excitatory neurotransmission
- reduces ACh release
Lowers MAC
- blocks brainstem release of NE, epi, dopamine
______ is the only nondepolarizing NMB agent that is metabolized by pseudocholinesterase
Mivacurium
- prolonged by pseudocholinesterase def.
LMWH more selectively inhibits ______ than UFH
activated factor X
Direct thrombin inhibitors
- Argatroban
- Bivalrudin
- Lepirudin
- Desirudin
Which abx potentiates NMB (prolonging paralysis)?
Aminoglycosides, clindamycin, tetracyclines
- inhibits prejunctional ACh release
- depress post junctional receptor sensitivity
Does intrathecal morphine alter MAC?
Does IV lidocaine decrease MAC?
Nope
Yea
Glycopyrrolate effect on: Gastric emptying Gastric secretions Upper esophageal sphincter tone Lower esophageal sphincter tone
*decreases parasympathetic tone
Gastric emptying: delayed
Gastric secretions: decreased
Upper esophageal sphincter tone: lower
Lower esophageal sphincter tone: lower
Which BP meds are contraindicated in pregnancy?
ACE-I