Pharmacology Flashcards
An otherwise healthy child with developmental delay has poor dental hygiene, and you are concerned about tooth decay. A dental examination has been tried without success.
What sedative agent would you recommend?
Nitrous oxide
Explanation
Nitrous oxide provides mild analgesia, sedation, and amnesia. It is also an anxiolytic agent. The recovery is immediate once the gas delivery is stopped. For these reasons, it is a frequent choice among dentists.
A patient is scheduled for a colonoscopy under moderate sedation.
Name a possible contraindication to moderate sedation in this scenario.
Not enough support personnel
Explanation
Patients undergoing moderate sedation require not only continuous pulse oximetry, blood pressure, and cardiorespiratory monitoring, but a medical provider and support personnel must be at the bedside during the procedure. This requires at least 2 people: 1 to do the procedure and 1 to monitor the patient.
A teenager presents to the emergency department with an acute traumatic fracture. She is given a 1-week supply of pain medication. She returns to the emergency department later that night with slow, sonorous respirations, lethargy, and confusion. On physical examination she is hypothermic and bradycardic with pinpoint pupils and decreased bowel sounds.
After initial management based on airway, breathing, and circulation, what is the most appropriate drug to administer to this patient?
Naloxone
Explanation
This patient illustrates the classic toxidrome for acute opioid intoxication. Naloxone is an opioid antagonist and is the preferred treatment for an acute overdose. Naloxone’s effect lasts 20–90 minutes; re-administration of naloxone is sometimes required.
Because opioids can cause respiratory depression and apnea, your initial assessment focuses on the ABCs: airway, breathing, and circulation. You should be prepared to maintain airway and support ventilation.
A young child requires a short, minimally invasive procedure. The child and parents are concerned that it might be painful.
Name a strategy that can be employed to reduce the child’s and parents’ anxiety.
Answer
Partner with a child life specialist
Explanation
Child life specialists are health care professionals who incorporate play, relaxation, and behavioral interventions to help children during painful and anxiety-provoking procedures
An adolescent with a developmental disability, who requires a brain MRI scan, is given propofol for sedation. You are asked to monitor him during the procedure and recovery.
What are the potential adverse effects of procedural sedation with propofol?
Respiratory depression, apnea, bradycardia, and hypotension
Explanation
Every patient should be monitored by at least 2 medically qualified providers during sedation. In this case scenario, cardiorespiratory and BP monitoring are required. Some of the reasons responsible for sedation-related adverse effects include:
Lack of familiarity with the specific drugs, including pharmacokinetics, interactions, and duration of action of specific drugs
Inadequate patient medical history (Propofol is absolutely contraindicated in patients with a history of porphyria.)
Lack of adherence to procedural guidelines, including adequate monitoring
Inadequate medical personnel and/or support staff
You are prescribing a medication with first-order drug elimination.
Assuming that a loading dose was not given, how many half-lives would be necessary to reach a steady state?
Half-Lives 1 2 3 4 5
Answer
5
Explanation
First-order kinetics: The rate at which a drug is eliminated is dependent on (proportional to) the drug concentration. When a drug is following first-order kinetics, the serum concentration of the drug is half of the initial concentration after 1 half-life (see table). It will take approximately 5 half-lives to reach a steady state (at 97%), meaning the medication will be 97% cleared after 5 half-lives.
% Steady State 50 75 88 94 97
A child is diagnosed with malaria and treated with oral primaquine. He develops nonimmune hemolytic anemia, and it is discovered he has glucose-6-phosphate dehydrogenase deficiency.
How would you classify this reaction?
Idiosyncratic adverse drug reaction
Explanation
The term “idiosyncratic adverse drug reaction” refers to effects that are not dose dependent or related to the known pharmacological actions of the drug. They are often difficult to predict, can arise from genetic differences in the patient, and have variable presentations. Primaquine causing nonimmune hemolytic anemia in patients with glucose-6-phosphate dehydrogenase deficiency is an example of this reaction.
A child is given deep sedation during a medical procedure.
What level of monitoring is recommended for this child?
nswer
Continuously monitor oxygen saturation, respiratory rate, and cardiac rate/rhythm. Bedside support staff and bedside practitioner monitor blood pressure every 3 minutes.
Explanation
Deep sedation produces deep sleep. These patients are not easily aroused and have partial or complete loss of protective airway reflexes. They require airway maintenance and respiratory support. For this reason, follow them closely with pulse oximetry, cardiorespiratory monitoring, and medical supervision.
You prescribe simvastatin for an adolescent with hypercholesterolemia.
What food or drink should be avoided while taking this medication?
Grapefruit and grapefruit juice
Explanation
Foods, supplements, and other medications can interact with drugs; for example, they can alter absorption. In the case of simvastatin (a medication used in the treatment of elevated cholesterol), grapefruit or grapefruit juice increases the level of simvastatin in the blood by inhibiting its metabolism by CYT P450 in the liver, and thus increasing the likelihood of side effects.
An infant is given narcotics for pain in the postoperative period.
What are the risks of narcotics in this age group?
Answer
Increased risk of apnea and hypoventilation
Explanation
Apnea and hypoventilation happen more frequently in infants being treated with opioids due to their decreased ventilatory responses to hypoxia and hypercapnia.
An adolescent presents to the emergency department with decreased level of consciousness, shallow respiratory rate, bradycardia, and hypotension. His pupils are constricted. An empty oxycodone bottle was found at the scene. He was in the emergency department only hours before with a severe fracture and had been prescribed oxycodone for pain. He has no history of substance use.
How would you manage this patient?
nswer
Provide supportive care and monitoring, with special attention to oxygenation and ventilation; give naloxone.
Explanation
This scenario is the classic toxidrome for opioids: respiratory depression, altered mental status, and miosis. Oxycodone is given orally for moderate-to-severe pain control. Its onset of action is 20 minutes, and the duration of action varies with the type of preparation: short-acting (3–6 hours) or long-acting (12 hours). Naloxone is an opioid receptor antagonist and is the reversal agent for opioid overdose. Be prepared to support oxygenation and ventilation, and perform cardiopulmonary monitoring based on clinical features and drug levels. Even after a satisfactory response to naloxone, respiratory depression may recur when overdose involves a long-acting preparation of oxycodone.
An adolescent with HIV is on a therapeutic regimen that includes indinavir. Following many months of treatment with therapeutic blood levels, you find that you are no longer able to maintain levels. Review of the patient’s clinical and pharmacy charts reveals no new medications; however, she reports sadness and depressed mood after losing a close friend to AIDS. Her mother suggested St. John’s wort, which she has been taking for a few weeks now.
What should you suggest to this patient?
Discontinue St. John’s wort immediately.
Explanation
St. John’s wort induces the hepatic cytochrome P-450 system, through which indinavir is metabolized in liver. Addition of St. John’s wort to indinavir increases its metabolism and therefore decreases the effectiveness of indinavir.
Patients do not always include complementary medications when they provide drug lists. Ask patients about complementary therapies, and caution them that these can interact and interfere with their therapeutic medications.
A child with advanced cystic fibrosis needs an arterial blood gas. You would like to provide dermal analgesia for the procedure.
What analgesic agent would be appropriate?
Eutectic Mixture of Local Anesthetics (EMLA)
Explanation
EMLA is used topically (under an occlusive dressing) on intact skin. Its onset of action is 1 hour, and it lasts up to 1–2 hours after the dressing is removed. It provides dermal analgesia for procedures such as lumbar punctures, arterial blood sampling, and IV placement. It is contraindicated in patients with an allergy to amide anesthetics, such as lidocaine and prilocaine. Excessive use in infants has been associated with methemoglobinemia.
A child with newly diagnosed leukemia is scheduled to undergo a bone marrow biopsy. The child is anxious and frightened about the procedure. You opt to administer a minimal level of sedation to minimize her anxiety during the procedure.
What level of medical supervision is recommended?
Answer
Observation via intermittent assessment by a supervising practitioner
Explanation
In a child with normal baseline respiratory and cardiovascular function, you can expect the following during minimal sedation (anxiolysis):
Normal response to verbal commands
Protective airway reflexes maintained
Respiratory function intact
Cardiovascular function maintained
A young woman on phenytoin for epilepsy wants to explore her options for birth control.
Do you have any specific pharmacologic considerations when counseling this patient about her options?
Answer
Yes. Phenytoin may interact with birth control pills and decrease their efficacy.
Explanation
When you add a new medication, you must consider potential drug-drug interactions. These interactions may affect absorption, distribution and protein binding, metabolism, or excretion. Drugs may compete for the same receptors or have a synergistic effect, as in the case of concomitant use of aminoglycosides and cephalosporins. In the example from our question, phenytoin (an enzyme-inducing agent) affects the metabolism in a way that can decrease the efficacy of birth control pills, resulting in unplanned pregnancy
