A 36-year-old male is undergoing a major surgical procedure under general anesthesia.  A fluorinated inhaled anesthetic (isoflurane) is used to achieve the desirable depth of central nervous system depression.  An increase in which of the following parameters is most likely to happen during the anesthesia in this patient?

A group of investigators is studying the pharmacokinetic properties of the anesthetic drug propofol.  A radiolabeled formulation of the drug is prepared and a single bolus is administered to adult guinea pigs.  Blood and tissue samples are then collected at predetermined time intervals.  Concentrations of the radioactive drug in the samples are assessed by liquid scintillation counting.  The graph below demonstrates the drug concentration-time relationship in various tissues.

The red line on the graph most likely corresponds to which of the following tissues?

A 27-year-old woman comes to the office due to severe, unilateral, throbbing headaches that occur several times a month.  The headaches are associated with photophobia, nausea, and occasional vomiting.  Over-the-counter analgesics do not provide significant symptom relief.  Her mother has a history of similar headaches.  Vital signs are within normal limits.  Physical examination reveals no abnormalities.  A medication is prescribed to treat her condition and the patient is instructed to take it immediately at the onset of a headache.  This medication most likely decreases the severity and duration of this patient’s headache through which of the following mechanisms?

A new inhaled anesthetic under development by a pharmaceutical company is tested in a series of experiments to determine its pharmacokinetic properties.  During one of the experiments, the anesthetic agent is administered at a constant partial pressure while arterial and venous concentrations are monitored.  The study results show that the anesthetic has a very large arteriovenous concentration gradient shortly after beginning inhalation.  Which of the following best describes the properties of the new anesthetic?

A 21-year-old man is brought to the emergency department by his mother after she found him violently shaking on the kitchen floor of her home.  The patient urinated on himself and bit his tongue during the incident.  He has a past medical history of posttraumatic epilepsy and is noncompliant with his antiseizure medications.  In the hospital, he has several brief, back-to-back generalized tonic-clonic seizures and never fully regains consciousness between episodes.  Intravenous lorazepam 2 mg is administered, and the seizures stop.  Intravenous infusion of another drug is started simultaneously to prevent seizure recurrence.  Which of the following is the most likely mechanism of action of the second drug infused in this patient?

A 72-year-old man with a history of Parkinson disease comes to the office for follow-up.  The patient has been taking carbidopa-levodopa since being diagnosed 5 years ago and has required increasing doses to control his symptoms.  He is now taking the maximum dose but has experienced bothersome motor fluctuations for the past several months.  The patient also reports worsening stiffness and difficulty moving between his scheduled doses; these symptoms improve after he takes the medication.  Entacapone is added to his treatment regimen.  This drug is most likely to improve this patient’s symptoms through which of the following mechanisms?

A 62-year-old woman is brought to the emergency department because of acute chest pain.  She also complains of diaphoresis, nausea, and lightheadedness.  Her blood pressure is 90/60 mm Hg and pulse is 42/min.  An ECG reveals ST-segment elevation in the inferior leads.  The appropriate therapy is initiated, including a medication to treat her bradycardia.  After initial treatment, her blood pressure is 120/70 mm Hg and pulse is 76/min.  However, she now complains of severe right-sided eye pain.  Which of the following is the most likely cause for this patient’s eye pain?

A 45-year-old quadriplegic man with suspected bacterial pneumonia is admitted to the hospital and started on intravenous antibiotics.  Over the next 24 hours, he develops progressive respiratory failure requiring mechanical ventilation.  Prior to intubation, a skeletal muscle relaxant is administered and the patient subsequently goes into cardiac arrest.  His attached cardiac monitor shows ventricular fibrillation.  While he is being resuscitated, his serum potassium level is drawn and later comes back as 9.5 mEq/L.  Administration of which of the following agents is most likely responsible for this patient’s condition?

A 62-year-old man comes to the emergency department due to right upper extremity weakness.  Thirty minutes ago, the patient was at his office when he developed difficulty holding a pen.  His grip in the right hand was weak and he could not lift his right arm.  He tried calling his coworker but could not speak.  The patient has never had similar symptoms before.  He had no loss of consciousness, weakness of other extremities, vision abnormality, or headache.  The symptoms resolved spontaneously by the time paramedics arrived.  Medical history is significant for hypertension and a 30-pack-year smoking history.  The patient is a defense attorney and recently took on a high-profile case.  Temperature is 36.9 C (98.4 F), blood pressure is 140/84 mm Hg, pulse is 82/min and regular, and respirations are 14/min.  Physical examination shows no extremity weakness or sensory loss.  There is a left carotid bruit; the remainder of the examination shows no abnormalities.  Noncontrast CT scan of the head is normal.  Which of the following pharmacotherapies is most appropriate in management of this patient?

A 65-year-old man is undergoing rehabilitation after a stroke.  Ten days ago, he presented to the emergency department with abrupt onset of left upper and lower extremity weakness.  He has a history of hypertension, hypercholesterolemia, gastroesophageal reflux disease, and hypothyroidism.  He does not use tobacco, alcohol, or recreational drugs.  His blood pressure is 140/90 mm Hg and pulse is 72/min.  He has weakness and increased tone in the left upper and lower extremities.  Diazepam is prescribed in order to decrease muscle spasticity of involved extremities.  This patient should primarily be cautioned to avoid which of the following drugs?

A 15-year-old boy is brought to the office because of 3 months of sudden, brief jerking movements involving both arms.  The episodes usually occur shortly after awakening in the morning and are aggravated by sleep deprivation.  The movements are neither suppressible nor preceded by an urge to make a movement.  The patient has never lost consciousness and has no known medical conditions.  Family history includes a seizure disorder in his uncle.  Vital signs are within normal limits.  Physical examination shows normal development with no abnormalities.  Which of the following is the best initial treatment for this patient?

An 11-year-old boy is brought to the emergency department by ambulance after he briefly lost consciousness.  The patient’s mother found him on the kitchen floor shaking and jerking.  She believes that he was out of her sight for only a few minutes.  When asked about any other abnormal behaviors, she says that her son often stares into space and does not respond to questions during these episodes.  The patient has no known medical conditions or history of recent illnesses.  He is afebrile with normal vital signs.  The patient seems sleepy but is oriented to time and place and has no abnormalities on physical examination.  Several hours later, he is alert and says that he wants to go home.  Which of the following agents is the best long-term treatment for this patient?

A 5-year-old boy is brought to the emergency department due to recurrent, generalized tonic-clonic seizures over the past 24 hours.  The patient has been having high fever and flulike symptoms for the past 3 days.  He has a past medical history of febrile seizures at age 6 months.  He takes no medications and has no family history of epilepsy.  The patient’s temperature is 39.4 C (103 F), blood pressure is 110/70 mm Hg, pulse is 112/min, and respirations are 10/min.  He appears lethargic and does not follow simple commands consistently.  His neck is supple.  During the examination, the patient suddenly develops sustained, generalized tonic-clonic convulsions without fully regaining consciousness between episodes.  Which of the following describes the mechanism of action of the most appropriate initial therapy for his seizures?

A 43-year-old male with multiple medical problems including seizure disorder and mental illness comes to your office for the first time in order to establish a primary care physician.  On routine physical examination, you notice the findings shown in the photo below.

Which of the following is most likely responsible for the condition of this patient’s teeth and gums?

A 42-year-old woman is hospitalized for surgical removal of a mediastinal mass.  The patient has had intermittent episodes of double vision, difficulty chewing food, and weakness of the extremities for the past several months.  During evaluation she was found to have a circumscribed anterior mediastinal mass.  Preoperative nerve conduction studies revealed a decremental response to repetitive motor nerve stimulation.  She has no other medical conditions and does not use tobacco, alcohol, or illicit drugs.  The patient has no drug allergies.  Compared to a healthy individual, which of the following anesthesia-related medications is most likely to have increased potency in this patient?

A 26-year-old man comes to the office due to severe headaches that are increasing in frequency.  The patient describes episodic, right-sided hemicranial throbbing or pulsating headaches accompanied by nausea and photophobia.  The headaches began when he was in high school, but lately they have become more frequent and are affecting his work.  The patient takes nonsteroidal analgesics and sumatriptan for the pain and metoclopramide for nausea.  He has no other medical conditions and no drug allergies.  Vital signs are within normal limits, and physical examination shows no abnormalities.  A recent brain imaging study was normal.  Which of the following pharmacotherapies would be most helpful to prevent recurrences of this patient’s headache?

A 64-year-old man comes to the office with 2 months of episodic facial pain.  He describes sudden-onset, severe, electric shock-like pain over the right cheek and ear lasting several seconds.  The patient reports that activities like shaving and washing his face can trigger the pain and it is becoming more frequent.  He is a retired veteran and has a history of posttraumatic stress disorder.  Physical examination, including neurologic examination, is normal.  Laboratory studies for blood cell counts, electrolytes, and hepatic and renal function are normal.  The patient is started on a single drug therapy.  On a follow-up visit 3 months later, he reports symptom improvement but is found to have the following blood counts:

Which of the following is the most likely mechanism of action of the drug used in this patient?

A 23-year-old woman is brought to the emergency department after having a tonic-clonic seizure.  She has a history of epilepsy and takes phenytoin.  She does not use tobacco, alcohol, or recreational drugs.  Physical examination is unremarkable.  Laboratory studies show a lower than normal plasma phenytoin level.  This patient most likely recently started taking which of the following medications?

A 52-year-old woman comes to the office due to a hand tremor that has been present for several months.  It is most prominent while she is carrying out simple daily activities such as drinking from a glass or pouring from a tea kettle.  When asked if anything improves the tremor, the patient mentions that it subsides somewhat when she drinks small amounts of alcohol.  Family history is significant for similar problems in her mother.  Vital signs are normal.  Neurologic examination shows bilateral tremor in the upper extremities.  Which of the following is the best treatment for this patient?

A 6-year-old boy is brought to the office by his mother due to difficulty with his behavior in school.  She says that his teacher is concerned that he does not pay attention in class and his grades are dropping to the point he may need medication to help him focus.  The patient’s mother has noticed that at home he seems to stare into space for several seconds, multiple times throughout the day.  This occurs even when he is watching his favorite television show, and he seems to ignore her when she calls his name.  The patient has no previous medical problems and takes no medications.  He has an older brother with attention-deficit hyperactivity disorder and an aunt with epilepsy.  Which of the following is the most appropriate pharmacotherapy for this patient?

A 4-year-old boy is brought to the emergency department by his parents following a seizure.  The patient has had an upper respiratory illness for the last 2 days but has no previous history of seizures.  Today, he suddenly became unresponsive and his arms and legs started shaking for approximately 40 seconds.  The patient was alert when the paramedics arrived at his house.  In the emergency department, temperature is 40 C (104 F) and pulse is 110/min.  The patient appears tired but is alert and cooperative.  Physical examination shows clear nasal discharge and mild pharyngeal erythema but no nuchal rigidity or other neurologic deficits.  Which of the following is the most likely underlying cause of this patient’s seizure?

An 8-year-old boy is brought to the office by his mother for a routine checkup.  He was diagnosed with absence seizures a year ago and has been undergoing treatment with an appropriate antiepileptic agent.  The mother says that the patient is doing well and has not had any seizures since starting the medication.  His school performance has improved significantly, and he no longer gets in trouble for “staring off” in class.  He eats a well-balanced diet and is at the 50th percentile for height and weight.  Which of the following is the most likely mechanism of action of the medication used in this patient?

A 28-year-old man is undergoing a laparoscopic appendectomy for acute appendicitis.  Shortly after induction of anesthesia, the surgeon reports difficulty maintaining abdominal insufflation due to severe muscle rigidity.  Pulse is 130/min and the ECG tracing shows sinus tachycardia.  Physical examination reveals diffuse muscle stiffness.  Inhibition of which of the following is most likely to improve this patient’s condition?

A new inhaled agent (drug A) is tested in an experiment designed to characterize its properties as a general anesthetic.  Drug A’s partial pressure in arterial blood is shown on the graph below as a function of time after beginning inhalation.  A similar curve for nitrous oxide is also shown.  Both drugs are administered at the same partial pressure in the inspired gas.

Which of the following best describes the properties of the new anesthetic as compared to nitrous oxide?

A newly developed inhaled anesthetic has an improved safety profile compared to traditional fluorinated anesthetics.  Preliminary pharmacodynamic properties of the agent are determined through a series of experiments on human volunteers.  The tests show that the agent demonstrates relatively high potency.  Which of the following parameters best correlates with the potency of an inhaled anesthetic?

A 65-year-old woman comes to the office due to progressive difficulty with walking for the past year.  In addition, the patient has difficulty lifting her right leg to get into and out of a car, getting dressed using the right arm, turning over in bed, and peeling vegetables, especially with the right hand.  Examination shows lack of facial expression, cogwheel rigidity in all extremities, a shuffling gait, and a fine resting tremor of the right hand.  In addition to levodopa, carbidopa is also started, mainly to reduce the severity of the adverse effects of levodopa.  Which of the following adverse effects is most likely to persist despite adding carbidopa to the patient’s treatment regimen?

A 25-year-old woman with newly diagnosed seizures comes to the emergency department with fever and skin rash.  She had her first seizure 6 weeks ago, and an MRI of the brain revealed no structural lesions.  She was started on phenytoin 4 weeks ago.  Her temperature is 38.9 C (102 F).  There is a diffuse confluent erythema involving 60% of the body, palpable generalized lymphadenopathy, and symmetrical facial swelling.  Which of the following laboratory findings is most likely to be present in this patient?

A 38-year-old woman presents to your office because of sudden episodes of severe, right-sided facial pain.  She describes the pain as “a knife stabbing my face.”  The pain lasts several seconds and is usually instigated by a meal or teeth brushing.  There is no nausea or vomiting.  She denies any visual changes.  Her past medical history is significant for hyperlipidemia.  She drinks alcohol socially and does not use tobacco.  She has no family history of facial pain.  Her vital signs are within normal limits, and physical examination shows no rash.  Which of the following is the best initial treatment for this patient?

A 24-year-old man comes to the emergency department after injuring his shoulder.  He was standing on a ladder hanging pictures in his living room when he lost his balance and fell, impacting his left shoulder on the hardwood floor.  Radiographs show an anterior dislocation of the humerus.  Reduction of the patient’s dislocated joint is performed under procedural sedation with intravenous propofol.  A single bolus of propofol provides adequate sedation for the procedure, and he becomes clinically alert several minutes after administration.  Which of the following mechanisms most likely explains this patient’s rapid recovery from anesthesia?

A 44-year-old woman with a history of breast cancer comes to the office due to persistent back pain.  The patient was recently started on radiation treatment for several vertebral metastases.  She has taken acetaminophen and nonsteroidal anti-inflammatory drugs but continues to have severe pain.  On physical examination, she has tenderness over several lumbar vertebrae.  Neurologic examination is unremarkable.  The patient is started on oral morphine therapy.  Which of the following is the most likely direct effect of this medication on the spinal cord neurons of this patient?

A 30-year-old man comes to the emergency department with sudden onset of severe headache and confusion.  He has a history of autosomal dominant polycystic kidney disease.  Neurological examination shows no meningeal signs or focal neurological deficits.  CT scan of the head reveals blood in the subarachnoid space.  The patient is admitted to the critical care unit for further management.  On the fifth day after admission, he experiences new-onset weakness in the right arm and leg.  Which of the following medications could have most likely prevented the neurological complications this patient developed in the hospital?

A 14-year-old boy is brought to the physician by his mother for seizures.  His seizures are usually characterized as a blank stare and lip smacking, followed by generalized shaking.  The patient occasionally bites his tongue during the episodes and feels confused afterwards.  His seizures have been refractory to various antiepileptic medications, and he is started on lamotrigine.  The patient should be instructed to see his physician immediately if which of the following symptoms occurs?