Pharmacology 2 Flashcards
Which of the following drugs causes the LEAST increase in biliary sphincter tone?
Butorphanol, unlike most opioids, does not cause biliary spasm as it does not cause sufficient sphincter of Oddi contraction to increase pressure in the common bile duct.
Butorphanol is a synthetic mu agonist-antagonist opioid analgesic with partial agonist activity at the κ-opioid receptor.
Which of the following substances is produced when desflurane degradation occurs with a desiccated carbon dioxide absorbent?
Carbon monoxide and heat are produced from the degradation of anesthetic agents in the presence of desiccated carbon dioxide absorbent. Among today’s volatile anesthetics, degradation of desflurane produces the most carbon monoxide.
A 21-year-old G1P0 female at 38 weeks gestation is receiving magnesium therapy for preeclampsia. At what magnesium level would you expect to begin to see PR prolongation and QRS widening on an ECG?
Hypotension and bradycardia can begin to appear at levels of 5-6 mg/dL. ECG changes including prolonged PR interval and widened QRS begin to appear at 6-12 mg/dL. At levels of 18 mg/dL, the SA and AV node can become blocked leading to complete heart block. Cardiac arrest (asystole) is generally seen at levels of 20-25 mg/dL.
Treatment of hypermagnesemia is IV calcium.
Which of the following medications is contraindicated in a patient with congenital methemoglobinemia?
EMLA Contraindications Include:
- Allergy to amide anesthetics
- Concomitant class III anti-arrhythmic drugs
- Congenital or idiopathic methemoglobinemia
- Infants (< 12 months) receiving treatment with methemoglobin-inducing agents
The potency of an inhalational anesthetic gas can be estimated by knowing its solubility in which substance?
The Meyer-Overton correlation related the potency of anesthetics with solubility in olive oil.
TrueLearn Insight : The Meyer-Overton correlation led to the unitary hypothesis, which notes that a common mechanism accounts for all anesthetic actions.
A 67-year-old female is preparing to undergo a sigmoid colectomy for diverticulitis. She has anxiety and depression for which she takes St. John’s wort. Which enzyme is induced by St. John’s wort?
Induction of the 3A4 system increases the metabolism of alfentanil, midazolam, lidocaine, and oral contraceptives. Induction of the 2C9 system increases the metabolism of most NSAIDs. Oral contraceptives and anti-retroviral medications may be less effective when patients are taking St. John’s wort.
St. John’s wort is a drug used to help treat anxiety and depression. St. John’s wort has mild sedative properties, which can affect anesthesia. St. John’s wort should be used with caution in patients taking MAO-Is or SSRIs. Additionally, St. John’s wort has been associated with delayed arousal from anesthesia, and some argue that MAC may be decreased in patients taking a St. John’s wort.
In the setting of an ongoing viral respiratory pandemic, a hospital system is experiencing shortages of most commonly utilized intravenous sedatives due to an excessive number of mechanically ventilated patients. Which of the following strategies is MOST appropriate in this setting?
Drug shortages during periods of exceptional medical need force providers to consider alternate means of providing safe and effective care. A common way to decrease sedative requirements in the intensive care unit is to administer oral opioids through a gastric tube to provide a baseline level of analgesia that facilitates the patient’s tolerance of an endotracheal tube.
Which of the following best describes the meaning of the ED95 dose in reference to neuromuscular blockers?
The ED95 of a neuromuscular blocking drug is the effective dose required to achieve 95% block of a single twitch in 50% of individuals. ED95 doses are used to compare potency between drugs.
A 50-year-old man is started on spironolactone to treat secondary hyperaldosteronism. What side effect of the drug is he MOST likely to experience?
The most commonly described side effects of spironolactone are hyperkalemia, hyponatremia, gynecomastia, and impotence.
Which of the following inotropes prevents the degradation of cyclic AMP?
Milrinone is a selective PDE III inhibitor and decreases the hydrolysis of cyclic AMP. Milrinone also causes vasodilatation and decreased afterload. Milrinone is often used as an inotropic medication following cardiopulmonary bypass, for pulmonary hypertension, and during acute CHF exacerbation. However, chronic milrinone treatment has been associated with increased mortality.
Dobutamine is a synthetic catecholamine which acts on beta-adrenergic receptors. This leads to an increase in cAMP via G-protein-coupled receptors (GPCR). Levosimendan is a calcium sensitizing medication. Levosimendan increases cardiac sensitivity to calcium, thus increasing inotropy and CO.
Which of the following medications is MOST likely to prolong the QT interval?
Methadone can produce or worsen a preexisting prolonged QT interval, which can lead to the lethal arrhythmia, torsades de pointes. This risk is increased with concurrent use of CYP3A4 inhibitors.
Which of the following statements about doxorubicin is TRUE?
Doxorubicin is a chemotherapeutic agent that is potentially toxic to the cardiac, pulmonary, GI, hepatic, and renal systems. It is also potentially myelotoxic. The most severe complication is doxorubicin-induced cardiomyopathy with heart failure that is cumulative, dose-related, and may occur during or after termination of therapy. Acute cardiac toxicity may manifest on ECG as ST segment changes or dysrhythmias.
Which of the following is the MOST appropriate treatment for postoperative delirium associated with scopolamine?
Physostigmine is an anticholinesterase with a tertiary amine structure that can be used as a treatment for central anticholinergic syndrome.
Which patient is MOST likely to have emergence reactions with ketamine administration?
Factors that influence incidence of emergence reactions:
Age: Adult patients are more likely to report a high incidence compared to pediatrics.
Gender: Females are more likely than males.
Dosage: Larger doses with rapid administration increase the risk.
Psychological Susceptibility: Certain personalities types are at an increased risk; those who tend to dream at home and those who score high on the Eysenck Personality Questionnaire (extrovert, neurotic) tend to have a higher risk.
Concurrent Medications: Multiple medications increase the incidence although administering a benzodiazepine prior to administration of ketamine helps decrease the risk.
Selected effects of ketamine:
- Dissociative sedation
- Possible emergence delirium
- Spinal analgesia
- Supraspinal analgesia
- Nystagmus, pupil dilation
- Increased salivation
- Increased vascular resistance from sympathetic outflow
- Bronchodilation with preserved respiratory drive
- Indirect myocardial stimulation (predominant)
- Direct myocardial depression
- Increased cerebral metabolism, CBF, and ICP
Which of the following drugs exerts most of its beneficial effects via the kappa opioid receptor?
Meperidine does have analgesic properties (potency 1/10 that of morphine) mediated by both mu and κ receptors. The major subtypes of opioid receptors include µ, κ, and delta (δ). The µ receptor is responsible for the most commonly recognized properties of opioids and has three subclasses. The µ1 receptor produces the analgesic and physical dependence properties of most opioids while stimulation of the µ2 receptor results in respiratory depression, miosis, euphoria, decreased gastrointestinal motility, and physical dependence. The actions of µ3 receptors are unknown but may mediate some anti-inflammatory activity.
The κ receptor mediates analgesia but also dysphoria, sedation, miosis, and inhibits antidiuretic hormone release. The δ receptor is responsible for analgesia, physical dependence, and perhaps antidepressant effects.
