Pharmacology 5 Flashcards
You would expect which of the following with furosemide administration?
Furosemide administration can cause a hypokalemic-hypochloremic metabolic alkalosis secondary to potassium excretion and a contraction alkalosis.
Which of the following drugs has the shortest duration of action at the benzodiazepine receptor?
Flumazenil has the shortest elimination half-life of all currently used benzodiazepines, which makes recrudescence of sedation after a single administration of flumazenil likely.
Which of the following is the mechanism for the suppression of cortisol synthesis after etomidate administration?
Etomidate causes adrenocortical suppression primarily through inhibition of adrenal mitochondrial 11β-hydroxylase, resulting in reduced cortisol (and aldosterone) production.
A patient receives local anesthetic subcutaneous infiltration and develops urticaria. Upon review of the vial, it is a multi-dose vial of lidocaine without epinephrine. Assuming this is, in fact, an allergic reaction to the injected medication, which of the following is the MOST LIKELY causal agent?
True allergic reactions to local anesthetics are rare. Aminoester local anesthetics are more likely to elicit allergic reactions compared to aminoamides because they are derivatives of para-aminobenzoic acid, a known allergen. Also potential allergens are the preservatives included in some formulations, methylparaben (structurally related to PABA) and sulfites.
TrueLearn Insight : Injectable 1% diphenhydramine, in addition to its antihistamine effect, is a safe, inexpensive, and effective local anesthetic for simple dermal procedures (e.g. sutures) in patients who report “-caine” allergies.
Which of the following is a known potential side effect of ingestion of large quantities of natural licorice?
Natural licorice contains glycyrrhizic acid which inhibits 11-beta-hydroxysteroid dehydrogenase (11-BHD). This inhibition allows cortisol to activate Na-K-ATPase channels in the renal proximal tubules leading to hypokalemia.
Large quantities of natural licorice will induce hyperaldosterone-like effects including: hypokalemia, hypertension, hypernatremia, fluid overload, and metabolic alkalosis.
A 65-year-old with chronic obstructive pulmonary disease (COPD) is given 70 mcg/kg of neostigmine after a four-hour bowel resection where profound neuromuscular blockade was required by the surgeon. Ten minutes after extubation, the PACU nurse calls and states the patient’s oxygen saturation has fallen to 84% and the heart rate has gone from 75 to 115 bpm. The patient reports the inability to take deep breaths. What is the next BEST step?
The patient is most likely experiencing residual neuromuscular blockade and ventilation should be assisted. Additional doses of anticholinesterases provide no benefit once the acetylcholinesterases are completely blocked. Use of doses larger than maximum for anticholinesterase drugs can result in a depolarizing blockade.
Right subclavian central venous access is attempted on a patient undergoing exploratory laparotomy under general anesthesia with 75% nitrous oxide and 0.3% isoflurane. Access is unsuccessful and during the last attempt, the syringe fills with air. Which of the following events is MOST likely to occur?
A pneumothorax, which can rapidly grow in size with nitrous oxide use, can cause difficulty with ventilation and increased peak airway pressures in intubated patients.
. Gas mixture of 75% N2O can expand a pneumothorax to double its size in 10 minutes and to 3 times its size in 30 minutes.
TrueLearn Insight : The volume of an air embolus causing cardiovascular collapse during the concomitant administration of N2O is less than the volume of an air embolus causing cardiovascular collapse in the absence of N2O.
Which of the following is LEAST likely to potentiate the neuromuscular blocking effects of vecuronium?
Prolong Non-Depolarizing Blockade:
- Antibiotics (e.g. streptomycin, clindamycin, tetracyclines, aminoglycosides)
- Antiarrhythmics (e.g. calcium channel blockers)
- Dantrolene
- Ketamine
- Local anesthetics (high doses only)
- Lithium
- Magnesium
- Volatile anesthetic agents
Shorten Non-Depolarizing Blockade:
- Anticonvulsants (e.g. phenytoin, carbamazepine)
- Cholinesterase inhibitors (e.g. neostigmine)
Which of the following diuretics is NOT known to cause hypokalemia?
Potassium-sparing mnemonic: The K+ STAys with spironolactone, triamterene, amiloride.
During cardiopulmonary bypass, which of the following is MOST likely to result in activated clotting time variability?
Factors that can result in variable ACT include: hemodilution, hypothermia, platelet counts below 30-50 k/mL, concomitant administration of other medications which affect platelets (e.g. prostacyclin, aspirin, glycoprotein IIb/IIIa inhibitors), general anesthesia, and surgery which alters coagulation in general but also affects the ACT.
You are called to see a patient in the PACU after endoscopic retrograde cholangiopancreatography. Medications they received for their anesthetic, in order, were temazepam, lidocaine, fentanyl, propofol, rocuronium, morphine, glycopyrrolate, and neostigmine. The patient is complaining of worsening right upper quadrant pain in the PACU. Which of the following is MOST appropriate?
Opioids can induce biliary colic, particularly in susceptible patients. This can be alleviated by blocking opioid receptor activation or by blocking parasympathetic activation. - Atropine papaverine
Which of the following statements about the use of a transdermal scopolamine patch for the prevention of postoperative nausea and vomiting is MOST likely TRUE?
Scopolamine is an antimuscarinic drug that, when applied as a transdermal patch, can help prevent or treat PONV for up to 72 hours. The patch should be applied at least four hours prior to the need for its antiemetic action. The patch should never be cut or otherwise damaged as this can alter drug delivery. Common side effects include blurred vision, dry mouth, and agitation. Scopolamine is relatively contraindicated in patients with glaucoma since the drug’s mydriatic and cycloplegic effects can raise IOP.
TrueLearn Insight : Scopolamine can cause paradoxical bradycardia when given in low doses (0.1-0.2 mg).
Which of the following cholinesterase inhibitors is the BEST to combine with atropine to reverse a nondepolarizing neuromuscular blocker?
A cholinesterase inhibitor should be paired with an anticholinergic agent with similar onset and duration of action in order to reverse nondepolarizing neuromuscular blockade and minimize cardiac muscarinic side effects. Neostigmine is typically combined with glycopyrrolate while edrophonium is paired with atropine.
Which of the following inhalational anesthetics decreases blood pressure primarily by decreasing cardiac output?
Sevoflurane, desflurane, and isoflurane decrease arterial blood pressure, SVR, and myocardial function comparably and in a dose-dependent manner. Halothane decreases blood pressure primarily by decreasing cardiac output and causes minimal changes to SVR.
TrueLearn Insight : Halothane is unlikely to be tested on the current American Board of Anesthesiologists exams. However, understanding the other volatile anesthetics allows for this question to be answered. Additionally, some physicians being trained in the U.S. travel for medical mission work to areas of the world where halothane is more commonly used.
Why does the alveolar concentration (FA)/ inspired concentration (FI) curve rise faster for nitrous oxide compared to desflurane?
The absorption of nitrous oxide is augmented by the concentration effect, making the rate of absorption faster than that of desflurane despite their similar blood-gas partition coefficients.
