American Board of Internal Medicine (ABIM) Certification Practice Exam

Which agent can help alleviate muscle breakdown in neuroleptic malignant syndrome?

1. Haloperidol

2. Dantrolene

3. Aspirin

4. Clonidine

The correct answer is: Dantrolene

Dantrolene is the agent that can help alleviate muscle breakdown in neuroleptic malignant syndrome (NMS). NMS is a serious and potentially life-threatening condition that can occur in response to antipsychotic medications, leading to severe muscle rigidity, hyperthermia, autonomic instability, and altered mental status. One of the key features of NMS is muscle breakdown, also known as rhabdomyolysis, which occurs due to prolonged muscle contraction and rigidity. Dantrolene acts by directly inhibiting calcium release from the sarcoplasmic reticulum in skeletal muscle, which helps to reduce muscle contraction and rigidity. This mechanism of action is critical in managing the symptoms of NMS and preventing further complications associated with muscle breakdown, including kidney injury due to elevated levels of myoglobin in the urine. While other options may play a role in the management of symptoms related to NMS, such as controlling fever or sedation, they do not specifically target muscle rigidity or mitigate the muscle breakdown associated with the syndrome comprehensively.