4.2 Pharmacokinetics Quiz

A 52-year-old (BMI 35 kg/m2) with schizophrenia presents for a routine follow-up. Abnormal, uncontrollable repetitive chewing-type movements in their jaw exist. These movements are bothersome and interfere with eating ability. The patient stays home because of shame about being seen in public. Medication history includes perphenazine for the past 8 years with good control of symptoms. The patient is able to live independently and care for themselves. Therapeutic trials of Aripiprazole, Ziprasidone, and Haloperidol have yielded subtherapeutic results. A 22.7-kg (50 lb) weight gain and development of type 2 diabetes occurred while taking Olanzapine. The diabetes resolved off Olanzapine. Which would be the best treatment?

A 36-year-old presents with a 16-year history of schizophrenia and alcohol use disorder. Medication was recently changed from haloperidol to aripiprazole because of gynecomastia and sexual dysfunction. Today, the patient is pacing in your office and seems anxious and agitated. The patient has not been sleeping well and feels uncomfortable in their skin. Which medication would be most appropriate to help relieve this patient’s symptoms?

A 67-year-old is admitted for new-onset tonic-clonic seizures. Medical history is negative for seizure disorders but positive for prediabetes and schizophrenia. The patient has long-term, stable schizophrenia controlled with clozapine 900 mg daily. Additional medications include Diphenhydramine 50 mg at bedtime, Metformin 1000 mg twice daily, and Bupropion extended release (ER) 300 mg daily (for 2 months). Social history is negative for alcohol and illicit drug use but positive for a 25 pack-year tobacco history, which was stopped 2 weeks ago. Which medication is most likely responsible for the seizures?

A 25-year-old presents to your practice with a depressed mood that has worsened during the past few weeks. The patient finds it difficult to get out of bed in the morning. When not sleeping, the patient is eating. Weight has increased by 4.5 kg (10 lb) in the past month. They are worried about their job and do not feel that they are “pulling [their] weight,” even though they recently received a glowing evaluation. They have passive thoughts of harming themselves but no definite plan. Medical history includes anxiety, gastroesophageal reflux disease, and hypothyroidism (thyroid-stimulating hormone [TSH] within normal limits). Current medications include Levothyroxine 100 mcg daily, Lansoprazole 30 mg every morning, and Alprazolam 0.5 mg three times daily for anxiety. Which medication would best treat the current symptoms?

A 56-year-old presents with a medical history significant for recurrent major depression and type 2 diabetes with newly diagnosed neuropathy, obesity, and coronary artery disease. Current medications include Citalopram 40 mg daily, Carvedilol 25 mg twice daily, Lisinopril 40 mg daily, and Metformin 1000 mg twice daily. The patient is tearful during the appointment and continues to have symptoms of depression despite initial improvement with Citalopram. The patient wants to change antidepressants. Which would be most beneficial?

A 50-year-old has a medical history significant for sleep apnoea, hypertension, type 2 diabetes, chronic pain, and bulimia. The current clinic visit is for an assessment of depressive symptoms and a medication evaluation. Described symptoms include sad mood, poor appetite (lost 6.8 kg [15 lb]), poor concentration, and feelings of hopelessness and worthlessness for the past 3 weeks. The patient also denies any use of alcohol, tobacco, or illicit drugs. Current medications include Hydrochlorothiazide, Metformin, Hydrocodone/Acetaminophen, and Aspirin. Which selective serotonin reuptake inhibitor (SSRI) would most likely interact with the current medications?

A 45-year-old presents with agitation and diaphoresis and an oral temperature of 38.5°C (101.3°F). Their right eyelid began twitching about an hour ago, and it will not stop. Cold symptoms developed 2 days ago and the patient began taking dextromethorphan and pseudoephedrine around the- clock. Medical history includes depression, hypertension, and dyslipidaemia. Current medications include cetirizine 10 mg at bedtime, Paroxetine 40 mg at bedtime, Diltiazem extended release (XR) 240 mg daily, and Rosuvastatin 10 mg daily. Which combination of medications is most likely contributing to the current symptoms?

A 31-year-old presents with a 5-year history of type I bipolar disorder, which is treated with lithium 300 mg twice daily. The patient has been adherent to treatment. A lithium serum concentration, obtained yesterday before the morning lithium dose, is 1.0 mEq/L. There have been no manic symptoms for the past few years. Current admission is for a suicide attempt using Acetaminophen. For the past few weeks, they have lost interest in their job and isolated themselves from other people. Which medication would best help the acute symptoms?

A 28-year-old woman (height 61 inches, weight 74.8 kg, up from 68 kg 2 months ago) presents with a history of type I bipolar disorder. She has taken lithium 450 mg twice daily for the past 6 months. Her last serum concentration (3 months ago) was 0.7 mEq/L. She presents today for an annual examination. Her laboratory test results include sodium 138 mEq/L, potassium 4.7 mEq/L, serum creatinine 0.9 mg/dL, glucose 124 mg/dL, and TSH 24 mIU/mL. Additional medications include Olanzapine 10 mg at bedtime (for 1 year), Ethinyl oestradiol/Drospirenone daily, and a multivitamin. Which laboratory finding is most closely associated with her current medication regimen?

A 43-year-old presents with right upper quadrant abdominal pain with rebound tenderness, nausea, and vomiting. Medical history is significant for rapid- cycling bipolar disorder, hypertension, obesity, and asthma. Current medications include Divalproex sodium 500 mg twice daily, Lamotrigine 150 mg twice daily, Aripiprazole 30 mg daily, Ramipril 10 mg daily, Albuterol hydrofluoroalkane (HFA) 2 puffs every 6 hours, and Fluticasone/Salmeterol dry powder inhaler 250/50 twice daily. A Prednisolone taper was initiated 3 days ago for an asthma exacerbation. Laboratory test results include sodium 141 mEq/L, potassium 3.3 mEq/L, chloride 95 mEq/L, carbon dioxide 26 mmol/L, SCr 1.0 mg/ dL, glucose 72 mg/dL, total cholesterol 165 mg/dL, triglycerides 188 mg/dL, aspartate aminotransferase (AST) 27 U/L, alanine aminotransferase (ALT) 21 U/L, amylase 456 U/L, lipase 387 U/L, and valproic acid trough concentration 56 mg/dL. Which medication is most likely responsible for the current clinical picture?

Patient John , has been 4 weeks since the initial visit with you, and the patient has been treated with citalopram 20 mg/day in the morning. Sad mood persists, but insomnia, concentration, and appetite have improved. Persistent symptoms include of hopelessness and worthlessness, lack of motivation, and anhedonia. No adverse affects exist. At this point, which is the best recommendation to optimize therapy?

A 20-year-old presents to the emergency department after experiencing trembling, sweating, chest pain, and shortness of breath accompanied by intense fear. A myocardial infarction has been ruled out. The patient is diagnosed with panic disorder. In addition to a medication for acute symptoms, which medication would provide the best long-term control?

A 55-year-old woman presents with uncontrolled generalized anxiety disorder (GAD). Concomitant medical conditions include a history of breast cancer, dyslipidaemia, osteoarthritis, vasomotor symptoms, and osteopenia. She takes tamoxifen, simvastatin, ibuprofen, lorazepam, and alendronate. Her physician would like her to have better control of her anxiety symptoms. He would also like to taper off lorazepam. Her GAD has not been controlled with paroxetine, sertraline, or duloxetine. Which agent would be best?

A 74-year-old has difficulty getting to sleep. Once asleep, rest is comfortable throughout the night. The patient has struggled with keeping a consistent bedtime for the past few months. There are no identifiable contributing factors. Concomitant medical conditions include hypertension, arthritis, and mild cognitive impairment. Diphenhydramine helped for only a few nights and “made me loopy.” They would like a medication with the least risk of hangover effect. Which medication is best?

A 23-year-old has a history of heroin addiction and has successfully been maintained on methadone 40 mg daily for 1 year. The patient would like an option that does not require a visit to a daily opioid treatment program to get their Methadone dose. The patient is taking no other medications or substances of abuse. Which treatment regimen is most appropriate?

A 55-year-old has a 30-year history of alcohol dependence. Daily intake is 1 pint of vodka. Several quit attempts have been unsuccessful. They recently reconciled with their estranged son and want to be sober so that they can be present in their son’s life. Medical history includes heroin use, depression, and posttraumatic stress disorder (PTSD). Concomitant medications include Methadone maintenance (which they wish to continue) and Sertraline (currently nonadherent). Liver function test results include AST 143 U/L, ALT 74 U/L, albumin 4.0 g/dL, alkaline phosphatase 75 U/L, total bilirubin 0.3 mg/dL, prothrombin time 15.1 seconds, international normalized ratio 0.9, platelet count 370,000/mm3, and creatinine clearance 40 mL/minute/1.73 m2. After alcohol detoxification, which maintenance treatment is most appropriate?

A 44-year-old is preparing to be discharged from the hospital after a myocardial infarction. Tobacco use includes a 25 pack-year history of smoking cigarettes and the patient smokes 1½ packs/day. Two unsuccessful quit attempts exist, including quitting “cold turkey” the first time about 5 years ago. Smoking resumed 6 months later after a job loss. Another attempt occurred 6 months ago using the 2-mg strength of nicotine gum. Seven pieces were chewed daily in an effort to save money. The patient has just been given a diagnosis of depression. Which regimen would be best?

25-year-old (BMI 35 kg/m2) has recently diagnosed schizophrenia. The patient often hears voices telling them they are “stupid and worthless” and should “just jump off the roof of their apartment building.” The patient’s parents became very concerned about isolative behavior and brought the patient to the hospital. The patient was given Haloperidol in the psychiatry unit and now presents with neck stiffness and in oculogyric crisis. Until now, they have not taken medications because they thought they could control their symptoms on their own with vitamins, though they have difficulty remembering to take these. The patient has an additional history of marijuana and alcohol use disorders. A blood alcohol concentration is 0, and a urine drug screen is negative. Which is most appropriate for this patient’s symptoms at this time?

30-year-old (BMI 40 kg/m2) has recently diagnosed schizophrenia, One year later, they no longer respond to Aripiprazole, and you decide to change their medication. They are only interested in oral medications. Given this patient’s history, which agent is most appropriate at this time?

A 36-year-old woman (BMI 20 kg/m2) with type I bipolar disorder presents to your clinic tearful, with a 2-week history of depressed mood, anhedonia, insomnia, feelings of worthlessness, and loss of appetite. She has passive thoughts of suicide, but no concrete plan. She currently takes lithium, with a trough serum concentration of 1.1 mEq/L. Which medication would be best to treat her current episode?

A 48-year-old has newly diagnosed generalized anxiety disorder (GAD). The patient cannot sleep at night and reports frequent headaches treated with Ibuprofen. Family history is positive for depression (mother) and anxiety (sister). Which medication would be best for long-term symptom resolution?

A recent Iraq war veteran has responded to treatment with paroxetine for major depression for the past 3 weeks. Clinical presentation today includes experiencing nightmares, “feeling on edge all the time,” and having flashbacks of time in the war. After evaluation, the patient is diagnosed with posttraumatic stress disorder (PTSD). There is no history of substance dependence and no significant medical history. Which recommendation is most appropriate for this patient at this time?

A 21-year-old has newly diagnosed OCD. They cannot hold a job because they are consumed by their obsessions and compulsions. They are convinced that their obsessions are reality. Which medication is most appropriate to initiate?

A 27-year-old with panic disorder is having difficulty functioning at work. The first panic attack occurred while getting a cup of coffee. It felt like a heart attack and was evaluated at the local emergency department, where physical causes were ruled out. There have been several subsequent episodes. Place and time of repeat episodes are unpredictable. Absenteeism from work is high, and job security is thus a concern. The medical history is otherwise unremarkable. Which medication would most quickly allow the patient to return to work?

A 38-year-old nursery teacher presents to the clinic today with noticeable dark circles under the eyes. They have difficulty with sleep, mainly with staying asleep. It takes about 20 minutes to fall asleep, but after about 5 hours, they wake up and cannot fall asleep again for several hours. This pattern has negatively affected job performance, and they feel tired all the time. They once took diphenhydramine for sleep but had to miss work because of extreme drowsiness in the morning. They wonder whether they could take any other medications. Other medical problems include hypothyroidism (Levothyroxine 125 mcg at bedtime), hypertension (Hydrochlorothiazide 25 mg in the morning), chronic back pain (Ibuprofen 800 mg three times daily), and MDD (Citalopram 20 mg in the morning). Which adverse effect of Zolpidem would carry the greatest potential for harm in this patient?

A 50-year-old patient with a 25-year history of alcohol dependence was found unconscious after a drinking binge. The patient was first admitted to the medical unit for alcohol withdrawal symptoms before being transferred to the substance dependence unit. The last drink was 6 hours ago, and fluids have been initiated. The patient has had three alcohol withdrawal seizures in the past and an episode of delirium tremens. Significant hepatitis is also present, and liver function tests show AST 275 U/L and ALT 130 U/L. Additional laboratory test values include albumin 4.2 g/ dL, alkaline phosphatase 152 IU/L, and g-glutamyl transferase 470 units/L. Which medication is best for this patient’s alcohol dependence?

A 30-year-old patient with a 20-year history of alcohol dependence was found unconscious after a drinking binge. The patient was first admitted to the medical unit for alcohol withdrawal symptoms before being transferred to the substance dependence unit. The last drink was 8 hours ago, and fluids have been initiated. The patient has had three alcohol withdrawal seizures in the past and an episode of delirium tremens. Which symptom are you most likely to observe in the medical unit in this patient on admission?

A 34-year-old wants to stop using oxycodone. They have been buying it off the street and are using 160 mg daily. The patient has no interest in methadone maintenance but wants to enroll in an outpatient program. The last oxycodone dose was 24 hours ago. The patient is having some anxiety and muscle aches. Treatment will start in the clinic. Which is the best formulation and dose to initiate in this patient?

A 38-year-old school teacher presents to the clinic today with noticeable dark circles under the eyes. They have difficulty with sleep, mainly with staying asleep. It takes about 20 minutes to fall asleep, but after about 5 hours, they wake up and cannot fall asleep again for several hours. This pattern has negatively affected job performance, and they feel tired all the time. They once took Diphenhydramine for sleep but had to miss work because of extreme drowsiness in the morning. They wonder whether they could take any other medications. Other medical problems include hypothyroidism (Levothyroxine 125 mcg at bedtime), hypertension (Hydrochlorothiazide 25 mg in the morning), chronic back pain (Ibuprofen 800 mg three times daily), and MDD (citalopram 20 mg in the morning). Which agent is most likely contributing to insomnia?

A 70-year-old female patient presents to the clinic today with noticeable dark circles under the eyes. She have difficulty with sleep, mainly with staying asleep. It takes about 30 minutes to fall asleep, but after about 5 hours, they wake up and cannot fall asleep again for several hours. Which medication used for insomnia is most appropriate to recommend?

A 26-year-old with a history of type I bipolar disorder presents to the inpatient unit. Their spouse found them withdrawing their life savings from the bank. The patient states that they are the perfect candidate for the presidency. The patient has not slept in the past 48 hours and is hyperverbal. The patient is placed on an involuntary mental health hold for control of manic symptoms. There is a history of nonadherence to medications and the patient currently takes none. Previous medication trials include olanzapine and lamotrigine. Which treatment-emergent adverse effect would be of most concern and would require immediate evaluation if lithium were prescribed?

A 36-year-old woman (BMI 20 kg/m2) with type I bipolar disorder Today, during a clinic visit, they are confused and slurring their words. The current lithium serum concentration is 1.9 mEq/L. Current medications include amlodipine for hypertension, atorvastatin for dyslipidaemia, and zolpidem for sleep. They began running a week ago. They have been replacing fluids using an oral rehydrating solution (Gatorade) and taking Ibuprofen around-the-clock for pain. Which most likely contributed to this patient’s current clinical
situation?

Aripiprazole is initiated 25-year-old (BMI 35 kg/m2) has recently diagnosed schizophrenia. Which is the best rationale for this selection, given patient-specific factors?

N.T. is a 24-year-old woman receiving valproic acid for tonic-clonic seizures. Her most recent trough valproic acid concentration was 22 mg/L. Her most recent albumin concentration was 4.1 g/dL. Given this albumin level, which recommendation is best regarding her dosage?

Which statement best describes P-glycoprotein?

C.M. is a 55-year-old man who is initiated on phenytoin after a craniotomy. His current steady-state phenytoin concentration is 6 mg/L at a dosage of 200 mg/day by mouth. If his affinity constant (Km) is calculated to be 5 mg/L, which is most likely to occur if the dosage is doubled (to 400 mg/day by mouth)?

A antipsychotic drug assay is touted as having high specificity but low sensitivity. Which statement best describes what this means?

P.L., a 45-year-old man with end-stage renal disease on dialysis is receiving phenytoin 400 mg/day for a history of tonic-clonic seizures. His phenytoin concentration today is 13.6 mg/L, and his albumin concentration is 4.2 g/dL. Given his current concentrations, which change would best be recommended?

Which one of the following is a short-acting hypnotic?

Which one of the following is a short-acting hypnotic and better for sleep induction compared to sleep maintenance?

Which of the following sedative–hypnotic agents utilizes melatonin receptor agonism as the mechanism of action to induce sleep?

Which agent is best used in the A&E setting for patients who are believed to have received too much of a benzodiazepine drug or taken an overdose of benzodiazepines?

A 25-year-old woman has a long history of depressive symptoms accompanied by body aches and pain secondary to a car accident 2 years earlier. Physical and laboratory tests are unremarkable. Which of the following drugs might be useful in this patient?

A 51-year-old woman with symptoms of major depression also has angle-closure glaucoma. Which of the following antidepressants should be avoided in this patient?
.

A 36-year-old man presents with symptoms of compulsive behavior. If anything is out of order, he feels that “work will not be accomplished effectively or
efficiently.” He realizes that his behavior is interfering with his ability to accomplish his daily tasks but cannot seem to stop himself. Which of the following drugs would be most helpful to this patient?

Which antidepressant has, as its two proposed principle mechanisms of action, 5-HT1a receptor partial agonism and 5-HT reuptake inhibition?

Which antidepressant is the most sedating?

Which mood stabilizer is completely renally eliminated and may be beneficial for patients with hepatic impairment?

Which antidepressant has, as its two principle mechanisms of action, 5-HT2A receptor antagonism and α2 receptor antagonism?

Which agent is best known to have the side effect of decreasing the thyroid function of the patient being chronically treated with this agent?

How does high protein binding of a drug affect its half-life and elimination rate?

How does weak protein binding of a drug affect its affinity for target receptors?

How can protein binding influence drug-drug interactions?

In patients with renal impairment, what is a potential consequence of high protein binding?

How can protein binding affect drug efficacy?

In patients with hepatic impairment, what is a potential consequence of weak protein binding?

What can happen when a highly protein-bound drug displaces another drug from its binding site?

What is the primary plasma protein involved in drug binding?

Which mode of administration may result in significant first-pass metabolism?

Which mode of administration bypasses the gut and results in rapid and complete absorption?

What factor can influence the distribution of a drug administered via the parenteral route?

Which mode of administration is particularly effective for treating respiratory conditions?

What factor can affect the absorption of a drug administered topically?

Which mode of administration is often used for drugs with a low therapeutic index or for drugs that need to be administered over an extended period of time?

Which mode of administration involves rapid absorption of drugs due to a rich blood supply?

Which factor is NOT a consideration when choosing a mode of drug administration?

A 35-year-old patient with hypertension is prescribed a new medication. The drug has a rapid Tmax

In a 70-year-old patient with renal impairment, what is likely to happen to the Vd of a drug?

A drug’s Cmax is an important parameter for determining:

What parameter represents the time it takes for a drug’s concentration to decrease by half?

Which parameter provides information on the total exposure to a drug over a certain period?

What factor influences the volume of distribution (Vd) of a drug?

A drug with a long half-life will have:

A patient is prescribed a drug with a high molecular weight, low lipid solubility, and high protein binding. Which type of kinetics is this drug likely to follow?

What type of kinetics is associated with the elimination of ethanol?

In which type of kinetics is the rate of drug elimination constant, regardless of drug concentration?

Which type of kinetics is commonly observed for drugs with a high therapeutic index?

In which type of kinetics can pharmacokinetics be predicted using simple mathematical models?

Which type of kinetics is generally associated with drugs eliminated by renal excretion?

A patient taking an anticonvulsant has recently started on a new medication for acid reflux. They report a worsening of their seizure control. Which interaction may be responsible?

A patient with depression is prescribed fluoxetine. They also take a medication metabolized by CYP2D6. What effect may fluoxetine have on the other medication?

Which factor can influence the specific CYP450 isoform that is induced or inhibited by a medication?

A patient regularly consumes alcohol and starts a new medication metabolized by CYP3A4. What effect may chronic alcohol consumption have on the medication?

Which CYP450 enzyme is induced by smoking, potentially leading to reduced efficacy of drugs metabolized by this pathway?

A patient taking a medication metabolized by CYP3A4 starts drinking grapefruit juice daily. What effect might this have on the patient’s medication?