IV drugs Hall Flashcards
How Succinylcholine metabolized
by plasma cholinesterase
Metabolism of atracurium & Cisatracurium
by Hofmannn elimination & ester hydrolysis
Vecuronium & rocuronium metabolism
Hepatic & biliary excretion, limited renal excretion 10-25%
The only NMB excreted in urine are?
the long acting NMB; d-tubocuraine, pancuronium, doxacurium, & pipecuronium
Of the long acting NMB, which one is the most eliminated by renal?
Pancuronium (80%), the others are 70%, and D-tubocuriane has little liver excretion which makes it the least excreted by renal.
Are IV anesthetics safe in prophyrias?
Yes to most drugs, local anesthetics are avoided to avoid the confustion if neurologic complications devopls in postop period.
What special attention should be paid for in prophyria noninduciable form (non-drug induced)?
avoid excessive pressure or irritation to skin (during mask ventilation or taping, IV cath….) because their skin is very friable.
What are selective vs non-selective B-adrenergic receptors?
Propranolol, nadolol, pindolol & timolol.
B1 selectives are; Esmolol & metoprolol.
What is the preferred anti-emetic medication in Parkinson disease patients?
Zofran. Drugs that can produew extrapyramidal effects are C/I such as droperidol, promethazine, & thiethylperazine & metoclopramide
Succinylcholine is more resistance to MG or mysthenic syndrome (Eton-Lambert syndrome)?
MG (they have fewer Ach Recp, which occupied by Ab’s, however they are more sensitive to NDNMB).
Patients with Mysthenic syndrome are sensitive to both DNMB & NDNMB
Why succunylcholine is CI in ptn’s with Duchenne’s, Hunttingto’s?
_ risk of rhabdo, hyperkalemia, & cardiac arrest. CI in hunttingtons because these ptn’s have decreased plasma cholinesterase and can prolong response of succ
Dopamine dose effect?
0.5-3 ug/kg/min -> renal vasodilation & increase RBF.
3-10 ug/kg/min -> above effect + B-adrenergic.
10-20 ug/kg/min -> Beta & alpha
> 20 ug/kg/min -> Alpha predominate.
Which IV anesthetic changes from water soluble to lipid soluble upon interning exposure to blood pH?
Midazolam.
What is the max dose for epi to avoid ventricular arrhythmia?
5 ug/kg.
In patient undergoing halothane anesthesia are more sensitive to ventricular arrhythmia and dose should be < 2 ug/kg.
Anticholinesterase drug that crosses BBB?
Physistigmine; makes it useful in treating central anticholinergic syndrome (also called postop delirium, or atropine toxicity).
MOA of ketamine?
Interact with NMDA recp also monoaminergic, muscarinic, opoid recp as well as voltage sensitive Ca ion channels.
Which opioid has antcholenergic properties?
Meperidine.
its structully similar to Atropin, in contrast to other opoids it can cause tachycardia. its metabolites (normrperidine) a CNS-stimulant and can cause delirium & seizures esp in RF patients and long exposure.
Direct-acting sympathomimetic drugs?
Dobutamine, Dopamine, Epi, Isoprpterenol,Methocamine, Norepi, Phenylephrine
Indirect-acting sympathomimetic drugs?
Amphetamine & Mephentermine
Indirect-acting & some direct sympathomimetic drugs?
Ephedrine & Metaraminol
Opioid that cause greatest myocardial depression with large dose?
Meperidine.
it rarely cause bradycardia but can cause tachycardia with high doses. a decrease in contractility seen with large doses maybe related to local anesthetic properties.
Ketamine effects?
1) Hypertonus purposeful movements.
2) Increased salivation.
3) Amnesia.
4) Analgesia (Somatic > visceral).
5) + sympathetic (increase pulm artery pressure, HR, CO, myocardial o2 requirement & bronchodilation).
Ketamine metabolism?
by liver ctyochrome P-450 enzymes to norketamine, which is as potent as ketamine.
IV anesthetic can cause myocardial depression?
Thiopental. by decreasing ca influx into myocardial cells.
What NMB should be avoided in patients taking Echothiophate eye drops for ttx on glucoma?
This drug inhibits acetylcholinesterase, therefore succinylcholine & mivacurium should be avoided to avoid prolongation of their affect. its recommended to wait 3 wks after stopping Echothiphate.
In TOF stimulation, how much reduction of twitch height is a good indicator for intubation?
at 90-95%
if there is single twitch, the twitch height is depressed at least 85%, 2-4 twitches 70%-85% depression is seen.
Name the 2 major chemical classes of NDNMB?
Aminosteroids (-onium drugs) & Benzylisoquinolinium (-urium)
Histamine release by which NMBs?
1) Mivacurium
2) Atracurium ( with rapid and >2 doses administration).
3) D-Tubocuronium
4) Succinylcholine
Termination of norepi achieved by …?
- 80% by re-uptake into postganglionic sympathetic & reenters storage vesicles for future release. (small amount undergo metabolism by MAO instead oof storage)
- 20% diluted by diffusion away from receptors & can go circulation, finally metabolized by COMT in liver.
The incidence of ketamine emergence delirium can be decreased by administering … ?
Midazolam 5 minutes before induction.
Atropin & droperidol may increase ketamine emergence delirium if given periopertively.
How much increase in K after succinlycholine administered in RF patients?
~ 0.5 mEq/L which is similar in normal patients.
Name few drugs that enhance NDNMB?
Volatiles, IV local anesthetics, CCB, dntrolene, Mg, aminoglycosides antibiotics, litium.
Calcium dose not, in fact it antagonizes Mg.
Will patients with hyperparathyrodisim enhance NDNMB?
No, Hypercalcemia decreases sensitivity to NDNMB and shortens its duration of action.
Following medications are not recommended to DC periopertively due to Clonidine ... BB .... MAOI inhibitors .... TCA ....
- Rebound hypertenstion can develop after DC clonidine & BB.
- Risk for suicide with DC MAOI (-), keep in minde certain meds interact with MAOI (-) such as meperidine (ms rigidity & hyperpyrexia, and ephedrine (exaggerated hypertensive response).
- Withdraw sx can occur from DC chronic TCA therapy (such as malaise, chills, coryza & ms aching).
Since atracurium metabolized by Hoffmann & plasma choliinesterase, will ptn’s with atypical pseudocholinesterase experince prolonged paralysis after administration?
No. the plasma chollinesterase is different from pseudocholinesterase that metabolize succinylcholine.
If both cicatracurium and atracurium metabolized by Hoffmann elimination (pH & temp dependent) & ester hydrolysis, why atracurium not preferred in RF ptn’s compered to cicatracurium?
Atracurium also metabolized by plasma cholenisterase and its metabolite (Laudanosine) can pass BBB and cause CNS stimulation . this metabolite is kidney and liver dependent for excretion. Cicatracurium is more potent and has lower levels of laudanosine at equivalent ms relaxation dose
Pretreatment with NDNMB attenuate which side effects of succinylcholine?
Cardiac dysrhythmias, elevation of intragastric pressure & ICP, or mylagia can be attenuates them bu t not eliminates them.
However, Increase K, MH, or prolonged Ms paralysis from abnormal pseudocholinesterase are not attenuated by pretretment.
Antibiotics potentiate NMB?
1) Aminoglycosides (neomycin, streptomycin, gentamicin, & tobomycin).
2) Lincosamines (Clindamycin, & lincomycin).
Antibiotics would not affect NMB?
Erythromycin, tetracyclines, penicillins, & cephalosporins.
Name anticholinesterase commonly administered with atropin/glycopyrrolate, and which one is fastest?
Endrophonium (1-2 min) > neostigmine (7-11 min) > Pyridostigmine (16 min).
Because Atropin has faster action then glyco, Endrophonium used with atropin. if for example glyco given with endrophonium, a marked bradycardia will initially develop.
When is peak time after injury is a risk for hyperkalemia after succinylcholine administration?
10 - 50 days after initial injury and may persist for 6 months or more.
The most common S/E of flumazenil is …?
Nausea & Vomiting.
Whats the best combination of anticholenergic drugs (Atropi, glycopyrolate) with cholegergic drugs (Endrophonium, neostgmine, pyridostigmine)?
Depends on onset of action, the goal not to give a faster anticholenergic drugs than cholenergics and avoid marked bradycardia.
- Glycopyrrolate with Neostgmine (7-11 min)/pyridostigmine 16 min).
- Atropin + Edrophoniumv (1-2 min)
What are anesthetics that are contraindicated in patients with prophyria?
- Barbiturates
- Etomidate -> potentially porphyrinogenic in animals
- BZDs (diazepam)
- Anagisics (ketorolac, pentazocine)
- Hydonation anticonvulsants.
What is the first step if etomidate accidentally injected in artery?
Observe.
Although it causes pain on IV injection ~80%, it dose not result in detrimental (harm) effects to artery.
The combination of dentrolene and verapmil risk for?
Hyperkalemia.
What makes fentanyl faster then morphine?
its more lipid soluble. it rabidly redistributed from brain to inactive site (lipid tissues).
What is Azerotrope term refer to?
Mixture of 2 volatile anesthetics.
Volatile agent that is avoided in prolonged closed cranium procedures?
Enflurane & Desflurane-> they increases CSF secretion but decreases its absorption.
Halothane: decreases CSF secreation & increases its absorption.
Isoflurane: no effect on secretion but increases its absorption
What makes (RO)curonium a unique advantage then other NDNBM?
Its rapid onset (Rapid Onset = ROcuronium)
1.5-3 minutes with 0.3 mg/kg (other NDNMB ~3-7 min).
a larger dose 0.6 mg/kg the onset reduced to 1-1.5 min
What is the effect of acute hypokalemia on NMB?
Hypokalemia causes hyperpolarization and this cases resistance to DNMB and increase sensitivity to NDNMB.
What NMB causes significant release of histamine?
D-tubocurarine. (can result in significant hypotension and that is why is not given in large doses).
in general succinyl and benzylisoquinolinium (attracurium but not cisattracurium or doxacurim) risk for histamine release.
DUMBBLESS are symptoms of …. and treated with …?
Cholinergic stimulation (increased Acho levels) that occur with anticholinesterase poisoning leading to parasympathetic nerves system activation (Diarrhea, urination, Miosis, Bronchoconstriction, Bradycardia, Lacrimation, Emisis, Salivation, Sweating). ttx with Atropin. (Pralidoxime added to ttx nicotinic effects of elevation of Acho at neuromascular junction of Muscles such as wakness and apnea
Flumazenil can cause seizures in patients with …?
On chronic BZDs for long term sedation, and in patients with serious antidepressent overdose (twitching, rigidity, wide QRS, hypotension).