Pharmacology Flashcards
What antiemetic should MOST be avoided in patients undergoing assisted reproductive therapy?
Metoclopramide
Along with droperidol, metoclopramide is avoided in the assisted reproductive therapy population because it can cause increased prolactin levels. High prolactin levels have been shown to impair follicle maturation and corpus luteum function, decreasing the likelihood of a successful reproductive outcome.
The highest serum fluoride levels are seen following the administration of which volatile anesthetic?
Sevoflurane
How is mivacurium metabolized?
It undergoes hydrolysis by plasma cholinesterase at a rate equivalent to 88% that of succinylcholine
It therefore, would have a prolonged duration of action in a patient who is homozygous for atypical plasma cholinesterase
What are the common side effects of anticholinergics?
Hot as a hare: increased body temperature
Blind as a bat: mydriasis (dilated pupils)
Dry as a bone: dry mouth, dry eyes, decreased sweat
Red as a beet: flushed face
Mad as a hatter: delirium
Decreased intestinal motility and peristalsis (constipation)
Lower esophageal sphincter pressure is reduced
What is an adverse effect of prolonged intravenous administration of nitroglycerin?
Methemoglobinemia, which causes a false reading of SaO2 of 85% (whether the patient’s saturation is higher or lower)
Systemic opioids modify pain through action at what neurological site?
The substantia gelatinosa
What are the special characteristics of alfentanil’s pharmokinetics.
It has a very small volume of distribution, which is why it has a short elimination half-life (1.5 hr)
What are the manifestations of anthrax poisoning?
It is an influenza-like disease with cough, myalgia,fever and malaise.
After a few days, the patient improves, but the a couple of days later, the patient becomes much sicker with dyspnea, cyanosis, hemoptysis, stridor, and chest pain.
What is the most notable finding on CXR for anthrax exposure?
Widened mediastinum
What is the treatment for anthrax?
Ciprofloxacin and doxycycline
(Penicillin G was the treatment of choice, but weaponized anthrax has been engineered to be resistant to this medication)
What is the bacteriology of anthrax?
It is a gram-positive, spore-forming bacillus that is transmitted to humans from contaminated animals and their carcasses.
Inhalational anthrax is rare but has an 80% mortality rate.
Describe the 2 types of HIT. How is it diagnosed?
1) Mild form: shows a transient decrease in platelet count after heparin exposure.
2) Severe form: autoimmune-mediated, with IgG antibodies to heparin and platelet factor IV.
Diagnosis is made my observing a 50% drop in platelets after heparin exposure, recovery after discontinuation of heparin, and exclusion of other causes and confirmation of antibodies.
Methadone (potency vs. Morphine; where does it act; what ECG changes can it cause)
It is 3 times as potent as morphine
It can also act on NMDA receptors (mu receptors as well)
It can cause a prolongation of the QT interval
What effects does acute vs. chronic use of cocaine have on MAC?
Acute use of cocaine increases MAC, due to increased sympathetic discharge, which can lead to coronary spasm and STEMI
Chronic use does not affect MAC. Synaptic catecholamines are spent with chronic use and indirect pressors like Ephedrine are often ineffective in increasing the blood pressure
What does magnesium do at the neuromuscular junction?
It antagonizes the release of acetylcholine at the neuromuscular junction and therefore, potentiates both depolarizing and non depolarizing neuromuscular paralytics
What common medication lowers the activity of the plasma cholinesterase?
Medications that inhibit pseudocholinesterase are: neostigmine cyclophosphamide phenelzine pancuronium esmolol metoclopramide monoamine oxidase inhibitors (MAOIs) oral contraceptives
What dose of the benzocaine can cause methemoglobinemia?
Doses > 200-300mg
What effects does terbutaline have on electrolytes?
It is a beta1 & 2 agonist, with predominantly beta 2 properties. It therefore produces hyperglycemia, hypokalemia, and tachycardia
What effect does clonidine have on blood glucose?
Clonidine improves blood glucose control and decreases insulin requirements during surgery in type II diabetics by inhibiting sympathoadrenal activity as an alpha-2 agonist
How does Cimetidine effect hepatic drug metabolism? Name other drugs that are similar in effect.
It inhibits hepatic drug metabolism
Ketoconazole
Erythromycin
Disulfiram
Ritonavir
What are some common drugs that increase/promote hepatic drug metabolism?
Phenobarbital Phenytoin Rifampin Carbamazepine Ethanol
Which volatile anesthetic has the largest impact on global warming?
Desflurane has the highest potential to produce global warming (although all anesthetics are recognized as greenhouse gases)
Sevoflurane and Isoflurane may contribute almost equally when used in conjunction with high fresh gas flow rates and 60% nitrous oxide.
What drugs cause a histamine release and transient hypotension?
Morphine Atracurium Mivacurium Doxacurium d-tubocurarine
Because all of these drugs possess the benyzlisoquinoline structure
What effect does lithium have on anesthetic drugs?
Lithium decreases anesthetic requirements & interferes with the action of several anesthetic agents.
It prolongs the effects of barbiturates, benzodiazepines, succinylcholine and non depolarizing muscle relaxants.
It blocks the effect of ADH on the renal tubules
It can produce hypokalemia and hypercalcemia
What drugs are myotoxic?
Statins, carbon monoxide (CO), ethylene glycol, seizures, cocaine, and colchicine
What drug induces serotonin release, inhibits the reuptake of norepinephrine, antagonizes NMDA receptors, and has opioid-like activity?
Tramadol
What physiologically occurs when phenylephrine is given to a patient?
Efferent signals respond (to the increased pressure detected by baroreceptors found in the carotid sinus and aortic arch) by decreasing sympathetic activity, leading to decreased cardiac contractility, heart rate, and vascular tone.
What are some drugs that have a first-pass effect in the liver?
Metoprolol
Diphenhydramine
Lidocaine
What diuretic causes metabolic acidosis?
Acetazolamide, which is a carbonic anhydrase (CA) inhibitor that acts at the proximal convoluted tubule of the kidney, interfering with bicarbonate and sodium reabsorption, which cases a hyperchloremic metabolic acidosis.
What diuretic(s) cause metabolic alkalosis?
1) Loop diuretics such as furosemide and torsemide, which inhibit a Na+/K+ ATPase that ultimately results in loss of sodium, potassium, chloride, hydrogen ion, magnesium, and calcium.
2) HCTZ and metolazone both work at the distal convoluted tubule and inhibit NaCl cotransporter mechanism that results in the loss of sodium, potassium, chloride, hydrogen ion, and preservation of calcium (hypercalcemia).
How is chloroprocaine metabolized?
It is an ester local anesthetic metabolized by pseudocholinesterase.
How is esmolol metabolized?
By red cell esterase (NOT plasma-cholinesterase)
What drugs can lead to postoperative jaundice?
Acetaminophen Cephalosporins NSAIDs Insulin Contrast media Procainamide Thiopental Ranitidine Hydralazine
What drugs have been shown to decrease MAC?
Clonidine Lithium Opioids Barbiturates Lidocaine Neostigmine Pancuronium Hydroxyzine Ketamine Verapamil
What herbal medication can decrease the hepatic metabolism of anesthetic agents and cause delayed emergence?
St. John’s Wort, which is frequently take for anxiety, insomnia, and depression
Side effects include:
hepatic enzyme induction
prolonged anesthesia
decreased metabolism of digoxin, warfarin, anticonvulsants and cyclosporin
What is licorice used for as an herbal medication? Side effects?
Gastritis and duodenal ulcers
Side effects:
Hypertension
Hypokalemia
Edema
Medicinal benefits of Purple Cone Flower? Side effects?
Treatment of burns, wounds, UTIs, and cough
Side effects:
Decrease corticosteroid effects
Medicinal benefits of Goldenseal? Side Effects?
It is used as a diuretic, anti-inflammatory, laxative, and hemostatic effects
Side effects: Ototoxicity Paralysis in overdose Edema Hypertension
What are the 4 ways to prevent platelet aggregation?
1) Cyclooxygenase inhibition (i.e. Aspirin) - lasts for the life of the platelet
2) Phosphodiesterase inhibition increases cyclic AMP and decreases platelet aggregation
3) Inhibition of the ADP receptor, and therefore blocking ADP-induced platelet aggregation (i.e. Ticlopidine and Clopidogrel)
4) Inhibition of glycoprotein IIb/IIIa receptors (i.e. abciximab and tirofiban)
Describe the symptoms of Digoxin toxicity
It characteristically produces transient numbness, tingling, and altered yellow vision with nausea and vomiting.
Which volatile anesthetic gas produces the most carbon monoxide (CO) by reacting with carbon dioxide (CO2) absorbents?
Desflurane
(When CO2 absorbents are maintained at or above room temperature, Desflurane under 1 MAC produces 8,000 ppm CO compared to Sevoflurane at 2 MAC, which produces 79 ppm CO.)
What properties of Cisatracurium make it appealing to use in ICU patients?
Its Elimination does NOT depend on end-organ function
Its metabolism depends on Hoffman elimination as well as ester hydrolysis
Hetastarch interferes with coagulation by decreasing the levels of which blood factor/component?
One liter of 6% Hetastarch decreases the levels of factor VIII by 50% and prolongs the aPTT
What is the half life of nitric oxide?
Less than 5 seconds
List the names of some common Angiotensin Receptor Blockers (ARBs)
Candesartan
Losartan
Valsartan
Act as vasodilators
What is the MOA of Trimethaphan
It is a vasodilator that is a ganglionic blocker
Name some common DIRECT vasodilators
Calcium channel blockers Hydralazine Minoxidil Nitroglycerin Nitroprusside Trimethaphan
List some common alpha-adrenergic blockers
Labetalol
Phentolamine
Prazosin
Terazosin
Act as vasodilators
List the names of common central alpha 2 agonists
Clonidine
Guanabenz
Guanfacine
What is Nesiritide and how does it act?
It is a vasodilator that BINDS NATRIURETIC FACTOR RECEPTORS
What illicit drug increases the risk of malignant hyperthermia with volatile anesthetics and succinylcholine?
MDMA “Ectasy-Molly”
What is the half-life of cocaine?
23.6 min
What is the treatment for patients exposed to organophosphates?
Leads to an anticholinergic crisis treated with Pralidoxime
What are the signs and symptoms of a cholinergic crisis?
Similar to a myasthenic crisis
Diarrhea Sweating Lacrimation Miosis Bradycardia Hypotension
What are the major side effects of beta blockers?
Hypoglycemia
Hyperkalemia
Bronchospasm
What is the treatment for acute dystonia that may arise as a side effect of metoclopromide?
IV Benztropine, an anticholinergic, is effective for most dystonic reactions with 5 minutes
What factors increase the rate of rise of FA?
1) Anesthetic concentration (FD); a higher FD leads to an higher FI, which increases the rate of rise of FA
2) Alveolar ventilation (VA); hyperventilation increases rate of rise of FA
3) Characteristics of the breathing circuit; high gas inflow from anesthesia machine speeds rise of FI
Which volatile anesthetic is the MOST soluble?
1) Methoxyflurane
Halothane is the second most soluble volatile anesthetic
What volatile anesthetic is the LEAST soluble? why?
Nitrous oxide is the LEAST soluble volatile anesthetic over Desflurane (2nd most) although Nitrous oxide has a higher blood gas solubility because of the high concentrations of nitrous oxide used
Xenon is actually the least
How does hyperventilation vs. hypoventilation effect the FI/FA ratio?
HYPERVENTILATION delivers more anesthetic to lungs INCREASING the rate of rise of FA/FI
HYPOVENTILATION thus DECREASES the rate of rise of FA/FI
How does cardiac output effect the FI/FA ratio?
As CO increases, the uptake increases, thus DECREASING the rise of alveolar partial pressure and slowing inhalational induction
How does a left to right cardiac shunt effect the FI/FA ratio vs. a right to left cardiac shunt?
Left to right: NO CHANGE in FA and NO change in induction
Right to left: DECREASED rise of arterial concentration of anesthetic and slower induction
How does FRC effect the FI/FA ratio?
An INCREASE in FRC yield more air space with a dilution of anesthetic and, therefore, DECREASES the rate of rise
A DECREASE in FRC (in pregnant patients) thus INCREASES the rate of rise
What enzyme in steroid synthesis is inhibited by Etomidate?
11 beta OH hydroxylase
What effect do barbiturates have on the brain?
- Vasoconstriction leads to decreased CBF
- CPP increases since the drop in ICP exceeds the decline in MAP (CPP = MAP - ICP)
- May protect the brain from FOCAL ISCHEMIA but probably not from GLOBAL ISCHEMIA
What does Ketamine dissociate?
It functionally “dissociates” the thalamus from the limbic system
MOA of Ketamine
NMDA receptor antagonism
also inhibits the reuptake of norepinephrine leading to its sympathomimetic effect
Describe Morphine’s lipid solubility
It has a very LOW lipid solubility and is known to be more hydrophilic
What opioid may depress cardiac contractility?
Meperidine (Demerol)
What subunit of the Na+ channel receptor local anesthetics bind to?
The alpha subunit
What affects nerve fiber sensitivity to local anesthetics?
The axonal diameter and myelination
- spinal nerves sensitivity is autonomic > sensory > motor
What is the key determinant of local anesthetic POTENCY?
Lipid Solubility
What are the 3 environments that antagonize local anesthetic blockade?
1) Acidic pH
2) HYPOkalemia
3) HYPERcalcemia
What is the key determinant of local anesthetic ONSET of action?
pKa
- the higher the pKa, the more is in ionized form at tissue pH
- local anesthetics with a pKa closer to physiologic pH will have a higher concentration of non-ionized base that can pass through the cell membrane
What is the main determinant of DURATION OF ACTION of local anesthetics?
Protein binding
Systemic absorption of local anesthetics is dependent on what?
Blood flow
What local anesthetics can cause methemoglobinemia? How is it treated?
Prilocaine and Benzocaine
Treatment with methylene blue IV 1-2 mg/kg of a 1% solution over 5 mins
What is the treatment for local anesthetic toxicity?
Infuse 20% Lipid Emulsion
*Bolus 1.5 mL/kg (lean body mass) IV over 1 min
(Repeat bolus once or twice for persistent CV collapse)
*Continuous infusion at 0.25 mL/kg/min
(Double infusion rate to 0.5 mL/kg/min if BP remains low)
Upper limit is ~ 10 mL/kg over the 1st 30 mins
What is the structure of the motor end plate?
It is made up of 5 sub units:
2 alpha subunits
1 beta subunit
1 delta subunit
1 gamma subunit
What is the significance of the Dibucaine number?
Dibucaine, an amide local anesthetic inhibits 80% of the activity of normal pseudocholinesterase
Therefore,
- 20% inhibition of atypical enzyme = homozygous
- 40-60% inhibition of atypical enzyme - heterozygous
What is the MOA of botulinum toxin?
It blocks the release of Ach from presynaptic vesicles
What can occur if Meperidine is administered to someone on an MAOI? Describe.
Monoamine oxidase is an enzyme that regulates presynaptic biogenic amines (NE, Dopamine, Epi, and serotonin). When inhibited, these amines build up at the presynaptic nerve terminal.
Merperidine & MAOIs can lead to SEROTONIN SYNDROME: excitation, hyperpyrexia, HTN, diffuse sweating, rigidity, seizures, coma, and death
What herbal medication can cause hepatotoxicity?
Echinacea
How does cAMP effect platelets?
cAMP inhibits platelet aggregation
What is the MOA of ticlopidine and clopidogrel?
They block the ADP receptor, and therefore INHIBIT ADP-induced platelet aggregation
What drugs inhibit platelet aggregation by inhibiting glycoprotein IIB/IIIa receptors?
Abciximab
Tirofiban
Eptifibatide (Integrilin)
How does the sympathetic nervous system effect the: eyes, lungs, heart, blood vessels, GI, bladder, uterus?
Eyes: Dilates pupils Lungs: Dilates bronchioles Heart: Increases heart rate Blood vessels: constricts blood vessels GI: Relaxes smooth muscles of GI tract Bladder: Relaxes bladder muscle Uterus: Relaxes uterine muscle
How does the parasympathetic nervous system effect the eyes, lungs, heart, blood vessels, GI, bladder, salivary glands?
Eyes: Constricts pupils Lungs: Constricts bronchioles and increases secretions Heart: Decreases heart rate Blood vessels: Dilates blood vessels GI: Increases peristalsis Bladder: Constricts the bladder Salivary Gland: increases salivation
What is the MOA of Prazosin (Minipress)?
It is an alpha blocker used to treat mild to moderate HTN
MOA of Pilocarpine
It is a direct acting parasympathomimetic (cholinergic agent) used in ophthalmic procedures
MOA of Bethanechol (Urecholine)
It is selective to muscarinic receptors and mimics the action of Ach (cholinergic agent) used for urinary retention
Define dromotrophy
Conduction
Define tonotrophy
Cardiac output
Define bathmotrophy
Excitability
Define chronotrophy
Heart rate
Define inotrophy
Contractility
How do amphetamines act at the neuromuscular junction?
They block the reuptake of NE and dopamine into the presynaptic neuron and increase the release of these monoamines into the extra neuronal space
Examples of cytotoxic drugs
Azathioprine Myclophenolate Mofetil Leflunomide Methotrexate Cyclophosphamide (alkylating agent)
Evidence of an anaphylactic reaction to a muscle relaxant 1-2 hours after the episode could be best established by blood levels of?
Tryptase, which is secreted by mast cells in the skin, lungs and intestines
Peaks between 15-120 min
How does meperidine reduce post anesthetic shivering?
The anti-shivering effect is most likely mediated by Kappa-opioid receptors
Which opioid receptor is most likely responsible for urinary retention?
The delta-opioid receptor
What antihypertensive decreases the peripheral conversion of T4 to T3?
Propranalol
Good treatment in patients with hyperthyroidism
What metabolic derangements can occur with lithium?
HYPOkalemia and HYPERcalcemia (it blocks the effect of ADH on the renal tubules)
What action of clonidine makes it beneficial to use in type II DM?
As a centrally acting alpha 2 agonist, it inhibits sympathoadrenal activity and provides better glycemic control
What is the MOA of fenoldopam?
Selective agonist on the dopamine type 1 receptor
Concurrent use of a tricyclic antidepressant (i.e. amitriptyline) and an anticholinergic (i.e. atropine) may result in what derangement/disease process?
Anticholinergic Syndrome
Hyperthermia, paralytic ileus, dry mouth, sedation blurred vision, confusion/delirium
Name common drugs with significant renal excretion
Neostigmine Atenolol Nadolol Normeperidine Penicillins Procainamide Pancuronium Rocuronium Quinolone Cephalosporins Digoxin
What is the potency of alfentanil?
10 times the clinical potency of Morphine
How does digoxin affect intracellular calcium?
It increases intracellular calcium (treated with Digibind - direct antibodies to digoxin)
Which opioid receptor is responsible for chest wall rigidity?
The mu receptor: pruritus, analgesia, biliary spasm, and chest wall rigidity
What is the ORL opioid receptor?
Is the the nociceptive receptor opioids stimulate and can produce tolerance to mu receptor effects, depression, and anxiety
What is the kappa opioid receptor responsible for?
Sedation and it has an antipruritic effect
How does Hetastarch interfere with coagulation?
One liter of 6% hetastarch decreases the levels of factor VIII by 50% and prolongs the aPTT
Which volatile anesthetic undergoes the greatest degree of metabolism?
Sevoflurane > Isoflurane > Desflurane
What anxiolytic should be avoided in patients treated for a long time on methylphenidate (Ritalin)? Why?
Clonidine (or Dexmedetomidine) because children on long time Ritalin treatment may have bradycardia and develop cardiovascular collapse at induction with its administration.
What is the most potent trigger for MH?
Halothane
Describe the second gas effect.
Administration of a less soluble gas with a more soluble gas results in an acceleration of the rise in the alveolar concentration of the more soluble gas
What are the side effects of chronic droperidol therapy?
Hallucinations
Loss of body image
Extrapyramidal side effects
Hypotension (secondary to alpha blockade)
What are the side effects of cyclosporine therapy?
Nephrotoxicity Hepatotoxicity Pancreatitis Peptic ulcers Neuropathies
What are the side effects of terbutaline?
Tachycardia Hypotension Myocardial ischemia Pulmonary edema Inhibition of Hypoxic Pulmonary Vasoconstriction (HPV) Hyperglycemia Metabolic (lactic) acidosis Hypokalemia Anxiety and nervousness
What is a characteristic side effect of mivacurium?
Transient flushing
What antiemetic is safely administered in patients with Parkinson’s disease?
Ondansetron
What are the signs and symptoms of hypermagnesemia? What is the treatment?
Signs/Symptoms: Nausea/vomiting & Flushing of the skin
Treatment includes:
Discontinue magnesium therapy
Administer calcium (antagonize magnesium effects)
Give IV fluids and forced diuresis (i.e. lasix), which will promote renal excretion of magnesium
MOA of buprenorphine
A mu receptor partial agonist (less euphoria and respiratory depression) and a kappa/delta (less craving and partial analgesia) receptor antagonist
Define the splitting ratio of a volatile anesthetic and how it is affected.
The splitting the ratio is the ratio of the flow between the bypass chamber and vaporizer chamber in variable bypass vaporizers.
The ratio is dependent on the temperature, the vapor pressure, the concentration, and the anesthetic agent itself.
As a volatile anesthetic increases, the FA/FI ratio of which agent will rise the most?
The most soluble VA (i.e. Isoflurane) agents will increase dramatically due to their propensity to diffuse into the blood and have a low baseline Fa/Fi ratio.
What anesthetic drugs have anticholinergic properties and can trigger an anticholinergic crisis?
Halogenated Inhalational agents (i.e. Desflurane, Isoflurane)
Propofol
Barbiturates
What is the MOA of amitryptiline and how does it cause cardiotoxicity?
It is a tricyclic antidepressant (TCA) that not only inhibits the reuptake of norepinephrine and serotonin, but also inhibits sodium and calcium channels, which is how it is cardiotoxic.
At what serum magnesium level do arrhythmias become apparent? SOB? Loss of DTRs? Sedation?
- Arrhythmias at > 20 mEq/L
- SOB with respiratory paralysis at > 15 mEq/L
- Loss of DTRs at > 10 mEq/L
- Sedation at 8 mEq/L
Chronic therapy with what drug is most likely to decrease a patient’s maximum dose of lidocaine?
Any drug that interferes with/inhibits the cytochrome P450 enzymes (i.e. Nicardipine)
What is the MOA of Rivaroxaban (Xarelto)? When should it be discontinued prior to elective procedures?
It inhibits Factor Xa directly and has a relatively short half-life or about 7-11 hours
It is stopped 24 hours prior to surgical intervention
What is the MOA of argatroban?
It is a direct thrombin inhibitor that has a very short half-life of about 39-51 minutes
Caution in patients with liver impairment
What is the MOA of Ticagrelor (Brilinta)? When should it be stopped prior to an elective procedure?
It is an inhibitor of platelet activation at the P2Y12 chemoreceptor for ATP.
It is co-administered with aspirin and is stopped 5 days prior to surgery?
What is the MOA of cilostazol (Pletal)?
It inhibits platelet phosphodiesterase III, which results in inhibition of platelet adhesion and aggregation
Describe opioid tolerance
A phenomenon that occurs when an individual over time requires greater amounts of a drug to continue to obtain the original degree of its desired, therapeutic effect.
It is marked by initial analgesia that seems to wane over time
Describe Pseudoaddiction
A drug-seeking behavior that simulates true addiction, which occurs in patients with pain who are receiving inadequate pain medication.
Patients cease taking increased doses of opioids once the pain is better controlled
Describe opioid-induced hyperalgesia
Patients who develop worsening pain with increased opioid dosing, which may be difficult to distinguish from opioid tolerance
What antibiotics DO NOT effect/ prolong the effect of neuromuscular blockade?
Ampicillin
Erythromycin
Cephalosporins
[Although PCN, aminoglycosides (gentamicin, kanamycin, amikacin, streptomycin, neomycin, and tobramycin), bacitracin, and polymyxins DO prolong the duration of NMB)]
How do beta blockers effect insulin secretion?
The SUPPRESS insulin secretion
How do beta blockers effect potassium during a KCl infusion?
An exaggerated INCREASE in potassium occurs during KCl infusion
What induction agent is associated with an increase in nausea and vomiting?
Etomidate
What are complications associated with TPN therapy?
- Hypercarbia
- HYPO or HYPERphosphatemia
- Metabolic acidosis
- Fatty acid deficiency
- HYPO or HYPERglycemia
- Sepsis
What are the side effects of 15-Methyl PGF2a (carboprost, Hemabate)?
Used to treat refractory uterine atony
Side effects include:
- fever
- diarrhea
- hypoxemia (due to intrapulmonary shunting)
- bronchospasm
- nausea/vomiting
MOA of heparin
It potentiates the action antithrombin III, allowing antithrombin III to act on factors VII, IX, X, and XI and inhibit their coagulant properties.
MOA ot tPA
activates plasmin to plasminogen
MOA of warfarin (Coumadin)
Inhibits factors 2, 7, 9, and 10 (vit K dependant) along with protein C and S.
MOA of clopidogrel (Plavix)
ADP receptor inhibitor
MOA of eftifibatide (integrillin)
IIb/IIIa inhibitor
What effect does 1 MAC of desflurane have on the respiratory system?
At 1 MAC, Desflurane :
- decreases tidal volume
- increases respiratory rate (although, this increase does not offset the decreased TV)
- overall decreased minute ventilation
- (therefore) mild increase in PaCO2
What is the maximum dose of bupivicaine with 1:200,000 epinephrine for a 70 kg patient? Tetracaine? Lidocaine? Mepivicaine? Etidocaine? Prilocaine?
Bupivicaine = 225 mg Tetracaine = 200 mg Lidocaine and Mepivicaine = 500 mg Etidocaine = 400 mg Prilocaine = 600 mg
Name cardioselective beta-1 antagonists
Atenolol
Betaxolol
Esmolol
Metoprolol
Name a nonselective beta antagonist
Propranolol
What volatile anesthetic will NOT cause an increase in heart rate and has minimal effects on SVR?
Halothane
What opioid causes decreased myocardial contractility when given in large doses?
Meperidine, possibly due to its anticholinergic properties
What organ can be effected by long term therapy with cyclosporine?
Kidneys
How does ketorolac effect the bladder?
It has been shown to effectively reduce the incidence and severity of bladder spasms and urinary retention after GU pediatric surgery
What drugs increase serum lithium levels?
ACE inhibitors Angiotensin II receptor antagonists (ARBS) NSAIDS Thiazide diuretics Tetracycline Metronidazole Cox-2 inhibitors
What drugs may decrease serum lithium levels?
Aminophylline Theophylline Acetazolamide Mannitol Sodium bicarbonate
[Spironolactone and furosemide have NO significant effect on serum lithium concentrations]
What is the MOA of Tramadol? What is its potency?
It is a weak opioid agonist at the mu receptor but also has properties of inhibition of NE and serotonin reuptake
It is one-tenth as potent an analgesic as morphine and has fewer respiratory effects.
Associated with seizure activity in those with a history of alcohol abuse
What is Nitric oxide’s MOA
Inhibition of cGMP resulting in dilation of pulmonary vascular beds.
What is the MOA of baclofen
It is a GABA-B receptor agonist, binding to presynaptic GABA receptors in the dorsal horn of the spinal cord, thereby decreasing the excitatory neurotransmitters
What is the duration of sulfur hexafluoride in the vitreous? vs. air
10 days vs. only 5 days with air
MOA of promethazine
A first-generation antihistamine of the phenothiazine family.
It is primarily a H1 antagonist with moderate Ach receptor antagonistic properties. It also has weak to moderate affinity for the 5-HT, D2, and alpha 1 receptors as an antagonist.
Another notable use is as a local anesthetic, by blockade sodium channels
In patients with PCN allergies, what cephalosporin can be given safely?
2nd (i.e. Cefuroxime), 3rd (i.e. Ceftriaxone), and 4th (i.e. Cefipime) generation cephalsporins are less likely to cross-react with PCNs.
[1st generation cephalosporins (i.e. Cefazolin) are the most likely class of abx to exhibit cross-reactivity)
What is the brain time constant? What is it for Sevoflurane?
It is 2 times the blood brain coefficient for the brain. It is also defined as capacity of a tissue to hold the volatile agent relative to the actual tissue blood flow.
For Sevoflurane: the brain/blood partition coefficient is 1.7, therefore twice that value would be 3.4 min.
What is the proposed mechanism for cardiac arrest from local anesthetic toxicity?
Local anesthetics REVERSIBLY bind to voltage gated sodium channels rendering them unable to generate and propagate an action potential
What effect does nitrous oxide have on muscle tone?
It, unlike other inhalational anesthetics, can cause an increase in muscle tone.
Why is mask induction with nitrous oxide faster than desflurane induction?
Despite nitrous oxide having a higher blood-gas solubility compared to desflurane…..
Due to the concentration effect, wherin the rate of rise of FA/FI is quicker because:
- nitrous oxide can be administered at much higher concentrations than desflurane and other gases —> the inspired partial pressure (FI) becomes so high that it causes the alveolar concentration (FA) of the gas to rise rapidly.
- higher inspired concentrations offset its diffusion into the blood, resulting in faster induction.
Vapor pressures of volatile anesthetics
N2O = 38,770 Desflurane = 670 (669) Halothane = 240 (243) Isoflurane = 240 (238) Sevoflurane = 160 (157) Enflurane = 170 (172)
What volume of vapor does 1 mL of most volatile anesthetics produce?
200 mL of vapor at 20 degrees Celsius
What is the MOA of Demeclocycline? Its use?
Demeclocycline is a tetracycline antibiotic that interferes with the action of ADH. By blocking ADH at its receptor, it impairs the ability of the kidneys to concentrate urine., which will worsen HYPERnatremia.
Utilized (off label) in treating SIADH
How are aminoglycosides metabolized?
They are minimally metabolized
[They are antibiotics that are NOT metabolized by CYP3A]
Name a selective beta-1 blocker?
Acebutolol (good to use in patients with asthma)
In comparison to fentanyl, alfentanil, sufentanil, and methadone, Morphine’s peak onset is Faster or Slower?
Slower
*compared to synthetic opioids, morphine is relatively hydrophobic and crosses the blood brain barrier much more slowly. The onset of all the other opioids is relatively fast (< 10 mins to peak effect). By contrast, morphine peak effect takes approx. 1 hr.
Hydroxyethyl starch is described as 2 numbers (e.g. 130/0.42, 670/0.75, etc.) What do these 2 numbers mean?
Average molecular weight/ molar substitution
What is the effect of 1 MAC of Sevoflurane on the cardiovascular system?
At 1 MAC, sevoflurane results in an increase in the QT interval, which usually does not lead to any clinical significance.
Cardiac output is maintained (a decrease in SVR is compensated by an increase in HR)
What are the common side effects of anticancer drugs such as Bleomycin, Doxorubicin, Cisplatin, and Vincristine?
Bleomycin —> pulmonary fibrosis
Doxorubicin —> cardiotoxicity
Cisplatin —> renal toxicity
Vincristine —> neurotoxicity (specifically peripheral neuropathy and vocal cord palsy)
What is the best test to monitor the activity of LMWH?
LMWH (enoxaparin) has a longer plasma half-life and more reliable efficacy than unfractionated heparin due to its smaller size and decreased peripheral protein binding.
The Anti-Xa Assay peaks at 4 hours (the advised time to conduct monitoring assays).
What advantages does cisatracurium have over atracurium?
- time to maximum block is slightly shorter, greater potency
- it is more cardiac stable because it lacks histamine release
- it has the same duration of action as atracurium
What level of CO2 is produced from the components of TPN (carbohydrates vs. proteins vs. fats) in regards to the RQ?
The respiratory quotient (RQ) is defined as the ratio of the amount of CO2 produced relative to the amount of oxygen consume (VCO2/VO2)
The RQ changes with the type of caloric intake.
Carbohydrates (sugars) have an RQ of 1
Proteins have an RQ of 0.8 - 0.9
Lipids have an RQ closer to 0.7
A higher RQ reflects greater CO2 production
