A patient on haloperidol develops sustained muscle spasm of the neck, oculogyric crisis, and arching of the back three days after starting the drug. This is best classified as:

• A Tardive dyskinesia
• B Akathisia
• C Pseudo-parkinsonism
• D Acute dystonia ✓

Explanation

Acute dystonia characteristically appears within hours to days of starting a dopamine antagonist (like haloperidol) and manifests as involuntary sustained muscle contractions — torticollis, oculogyric crisis, opisthotonos, and trismus. Tardive dyskinesia develops after months to years of treatment. Akathisia is motor restlessness without sustained muscle spasm. Pseudo-parkinsonism (bradykinesia, rigidity, tremor) develops after weeks.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.