Dystonic reaction


  • Adverse extrapyramidal effect shortly after initiation of new drugs
    • intermittent spasmodic or sustained involuntary contractions of muscles
  • Rarely life threatening but patient is in distress from pain and discomfort
  • Men > Women
  • Dystonia is idiosyncratic (not dose-related)

Predisposing Factors

  • Young age
  • Family history of dystonic reaction
  • History of EtOH or drug use
  • Associated with administration of antiemetics or antipsychotic medications (in 10-60% of treated patients)
  • 25% of patients treated with haloperidol have been known to develop this reaction
  • Reaction usually occurs within 48 hrs of drug treatment but can occur up to 5 days after starting therapy
  • Severity and onset of reaction depends on an individual, no association with dose, drug type, potency of drug, or duration of treatment

Medications Associated with Dystonic Reaction

Clinical Features

Medication-induced dystonia.
  • History of recent drug exposure or increase in drug dosage (e.g. prescription, over the counter, herbals, illegal)
  • Dystonia of any striated muscle group:
    • Torticollar reaction -> twisted neck or facial muscle spasm
    • Buccolingual reaction -> protruding or pulling sensation of the tongue
    • Oculogyric crisis -> roving or deviated gaze
    • Promandibular dystonia
    • Lingual dystonia
    • Opisthotonic -> severe hyperextension of entire spinal column
    • Kyphosis/lordosis/scoliosis
    • Trismus
    • Facial grimacing
    • Tortipelvic crisis -> abdominal rigidity and pain

Differential Diagnosis

Movement Disorders and Other Abnormal Contractions

Jaw Spasms

Neck pain


  • Normally a clinical diagnosis
  • Consider urine toxicology if no offending agent given by history
  • More chronic neurologic side effects of phenothiazines (akathisia, tardive dyskinesia, parkinsonism) don't usually respond as dramatically to treatment as does acute dystonia


  • Anticholinergic medication:
    • Benztropine: 1-2mg in adults over 2 minutes
    • Diphenhydramine: 25-50mg over 2 minutes
    • Biperiden
    • Trihexyphenidyl 2mg PO BID
    • IV > IM > PO
    • Symptoms will typically begin resolving in 2-15 minutes but may take up to 90 minutes to completely abate (depends on route in which medication was given)
    • Patients may require more than one dose of IV medication before symptoms resolve completely
  • Benzodiazepines
  • Airway Management
    • Rare, but may be indicated in patients with severe respiratory distress from laryngeal or pharyngeal dystonia


  • Stop the offending agent (if antipsychotic, speak with patients psychiatrist before just stopping the medication)
  • Continue to treat with PO anticholinergic to prevent relapse of symptoms (if the culprit is long acting)

See Also


  • Hockberger RS, Richards JR: Thought Disorders; in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2014, (Ch) 110: p 1460-1466.