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Human Pharmacology

Nursing

Quiz 12 :

Skeletal Muscle Relaxants

Quiz 12 :

Skeletal Muscle Relaxants

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A 54-year-old man with coronary artery disease is scheduled to undergo surgical excision of a tumor from his sigmoid colon. His cardiologist's recommendations included ensuring that his heart rate stay below 80 beats per minute during the procedure. The following muscle relaxant should be AVOIDED:
Free
Multiple Choice
Answer:

Answer:

A
Pancuronium causes vagal blockade and sympathetic stimulation, thereby placing the patient at risk for tachycardia.

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A 21-year-old man undergoing hernia repair receives succinylcholine before undergoing intubation and being anesthetized with sevoflurane, a halogenated volatile anesthetic agent. He suddenly becomes tachycardic, has an elevated temperature, develops muscle rigidity, his fraction of exhaled oxygen decreases, and his fraction of exhaled carbon dioxide increases. Which of the following skeletal muscle relaxants is most likely to reverse the symptoms he is experiencing?
Free
Multiple Choice
Answer:

Answer:

E
The patient is exhibiting symptoms of malignant hyperthermia (MH). Succinylcholine and halogenated volatile anesthetics are known to trigger MH episodes. MH is characterized by intense muscle contractions and increased metabolic demands. MH is believed to result from an intracellular derangement not involving cell membrane receptors. Dantrolene acts to decrease the intracellular release of calcium from the sarcoplasmic reticulum, thereby relaxing muscle tissue and reversing the symptoms of MH. Because MH is not mediated by cell membrane receptors, the other muscle relaxants listed are ineffective in its treatment.

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A 72-year-old woman in the intensive care unit has end-stage renal disease with a potassium level of 5.3 mEq/L and severely compromised hepatic function. She needs to undergo a debridement of a sacral decubitus ulcer. Which of the following would be the best skeletal muscle relaxant for use on this patient?
Free
Multiple Choice
Answer:

Answer:

C
Cisatracurium breaks down spontaneously in vivo ("Hoffman elimination"). Therefore its elimination is virtually unaffected by the patient's renal and hepatic dysfunction. Succinylcholine would have prolonged effects in this patient because its elimination is dependent on the hepatic production of plasma cholinesterase. Furthermore the increased potassium levels resulting from succinylcholine administration would be of particular concern in this patient with end-stage renal disease.