Which drug causes neck turning to one side or cervical dystonia (torticollis)?

NORCET 2 - 2021 (shift-1)

Pharmacology

Easy

Appeared in: NORCET 2 - 2021 (shift-1)

Explanation

Risperidone is an atypical antipsychotic medication.
Antipsychotics, both typical and atypical, are known to cause extrapyramidal symptoms (EPS) by blocking dopamine receptors in the brain.
Acute dystonia, which includes torticollis (involuntary neck twisting), is a type of EPS that can occur shortly after initiating or increasing the dose of an antipsychotic like risperidone.
This reaction is due to an imbalance created between dopamine and acetylcholine in the motor pathways of the brain.

Option A: Escitalopram is a Selective Serotonin Reuptake Inhibitor (SSRI). While it can have neurological side effects like tremors, it is not characteristically associated with causing acute dystonia or torticollis.
Option B: Phenytoin is an anticonvulsant. Its classic dose-related toxicities involve the central nervous system, but manifest as nystagmus (involuntary eye movements), ataxia (unsteady gait), and confusion. Gingival hyperplasia is a long-term side effect. Dystonia is a very rare side effect.
Option C: Valproate is an anticonvulsant and mood stabilizer. Common neurological side effects include tremor. While rare cases of dystonia have been reported, it is not a characteristic or common side effect compared to its other known effects like hepatotoxicity, thrombocytopenia, and weight gain.

Clinical Relevance

Nursing practice connection: Knowing Pharmacology: Side Effects of Psychotropic Medications helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Early recognition of acute dystonia is a critical nursing responsibility. It is a frightening and painful experience for the patient and can be life-threatening if it progresses to laryngospasm (spasm of the larynx), compromising the airway.
The standard emergency treatment for acute dystonia is the administration of an anticholinergic agent (like benztropine) or an antihistamine with anticholinergic properties (like diphenhydramine), usually given intramuscularly (IM) or intravenously (IV) for rapid effect.
What if? If a patient on risperidone develops torticollis and also has difficulty breathing or a high-pitched sound on inspiration (stridor), the nurse must immediately call for emergency assistance, as this suggests laryngospasm. Airway management becomes the top priority over administering the antidote.

How to Approach the Question

First, identify the core of the question: it's asking for a specific, dramatic side effect (torticollis/cervical dystonia).
Next, classify each of the drug options by its primary class: Escitalopram (SSRI), Phenytoin (anticonvulsant), Valproate (anticonvulsant), and Risperidone (antipsychotic).
Recall the major, characteristic side effect profiles for each drug class. Think about 'classic' associations taught in pharmacology.
Associate antipsychotics with Extrapyramidal Symptoms (EPS). Remember that acute dystonia (including torticollis) is a key type of EPS.
Compare this with the side effect profiles of the other classes. SSRIs are known for GI/sexual side effects, and anticonvulsants like phenytoin are known for nystagmus/ataxia. This makes the antipsychotic the most likely cause of the symptom described.
Select Risperidone as the answer based on the strong and well-known link between antipsychotics and acute dystonia.

Concept Tested & Keywords

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