Medical Pharmacology Clinical Case: Adrenergic, ephedrine, Pharmacology

Anesthesia Pharmacology: Autonomic Adrenergic Practice Clinical Case Questions

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A 35 yr. old, overweight female purchased a weight-reduction product which contained ephedrine.

She is using the product in accordance with directions on the label for one-month, then stopped using it during a vacation week, and then started again upon her return to work. Two days after restarting, she was awakened by anterior chest pain, which radiated to her left shoulder and arm.

She experienced numbness in the left arm,shortness of breath, and sweating (diaphoresis).

At the emergency department, she was treated with morphine and nitroglycerin.

Cardiac catherization revealed 60% narrowing of the left anterior descending coronary vessel and a
50 percent narrowing of the circumflex coronary artery.
There was no evidence of completely occluded coronary vessels.
ECG tracings indicated T-wave changes indicative of an acute myocardial
infarction, later confirmed by elevated cardiac enzymes.

Recovery was uneventful; the patient was discharged with instructions to avoid using the weight loss product or
similar weight loss products in the future.

(adapted from a case used in Medical Pharmacology, UCSF ,courtesy of Dr. Susan Masters, Dept. of Pharmacology, University of California San Francisco, used with permission.)

Primary mechanism of ephedrine (orally administered) cardiovascular action:
1. direct alpha receptor agonist
2. direct beta-1 receptor agonist
3. release of stored catecholamines (indirect action)
4. ephedrine not active following oral administration
5. release of stored histamine (indirect action)
Properties of ephedrine:
1. orally active
2. catecholamine
3. weak base
4. A & C
5. A, B & C
Possible explanations why ephedrine might cause myocardial infarction:
1. ephedrine may increase myocardial oxygen requirements
2. promotes coronary vasospasm
3. both
4. neither
In this patient, if it were concluded that coronary vasospasm was responsible for acute myocardial infarction, what drugs might reduce the likelihood of a recurrence.
1. propranolol
2. metoprolol
3. diltiazem
4. ergonovine
5. all the above
For what reason(s) was/were morphine used in the management of this patient?
1. pain relief
2. bradycardic effects
3. increases cardiac output
What is the major rationale for administration of nitroglycerin to this patient?
1. decrease myocardial oxygen demand
2. increase blood pressure
3. must be administered following morphine
What physiological factors might contraindicate the use of nitroglycerin in a patient with acute myocardial infarction?
1. low systolic arterial pressure (< 100 mm Hg)
2. clinical suspicion of right ventricular infarction
3. both
4. neither
In this patient, if acute myocardial infarction was caused by ephedrine-induced increased myocardial oxygen demand and if nitroglycerin were unable to reverse this effect, what alternative drug(s) might be effective?
1. alpha adrenergic blocker
2. beta-adrenergic blocker
3. both
4. neither