Caution is advised when using succinylcholine in patients with Huntington's chorea because

Caution is advised when using succinylcholine in patients with Huntington's chorea because

• A. They are at increased risk for MH
• B. Potassium release may be excessive
• C. They may have a decreased concentration of pseudocholinesterase
• D. There may be adverse interactions between succinylcholine and phenothiazine

Answer: (C)

Succinylcholine is rapidly inactivated in the plasma by the enzyme pseudocholinesterase. If this enzyme’s activity is reduced, the drug isn’t broken down as quickly, so the depolarizing block lasts longer and recovery of muscle function is delayed, leading to prolonged apnea and ventilation needs. In Huntington’s chorea, there can be decreased pseudocholinesterase activity, making this particular drug riskier because the duration of its effect is extended. The other concerns—malignant hyperthermia risk, excessive potassium release from upregulation of acetylcholine receptors, or adverse interactions with phenothiazines—are not as directly tied to Huntington’s chorea or to the primary reason to approach succinylcholine with caution in this context.

Succinylcholine is rapidly inactivated in the plasma by the enzyme pseudocholinesterase. If this enzyme’s activity is reduced, the drug isn’t broken down as quickly, so the depolarizing block lasts longer and recovery of muscle function is delayed, leading to prolonged apnea and ventilation needs. In Huntington’s chorea, there can be decreased pseudocholinesterase activity, making this particular drug riskier because the duration of its effect is extended.

The other concerns—malignant hyperthermia risk, excessive potassium release from upregulation of acetylcholine receptors, or adverse interactions with phenothiazines—are not as directly tied to Huntington’s chorea or to the primary reason to approach succinylcholine with caution in this context.