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Toxicity, Medication-Induced Dystonic Reactions: Treatment & Medication
Updated: Sep 30, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Emergency Department Care
- Emergency interventions other than pharmacologic treatment rarely are required.
- Securing the airway is necessary only rarely, when laryngeal and pharyngeal dystonic reactions place the patient at risk of imminent respiratory arrest.
- Pharmacologic treatment resolves the reaction.
Medication
The goals of pharmacotherapy are to reduce morbidity and prevent complications.
Anticholinergic agents
Intravenous anticholinergic agents are the treatment of choice. IV is the route of choice, with signs and symptoms often resolving within 10 minutes. The medication can be delivered IM if an IV line cannot be established, but medications will take 30 min to be absorbed. More than 1 dose may be necessary for complete resolution of dystonia.
Benztropine (Cogentin)
By blocking striatal cholinergic receptors, may help in balancing cholinergic and dopaminergic activity.
Adult
1-2 mg PO/IV/IM qd or bid; IV has most rapid onset
Pediatric
<3 years: Not established
>3 years: 0.02-0.05 mg/kg PO/IV/IM; not to exceed 2 mg/d
Decreases effects of levodopa; increases effects of narcotic analgesics, phenothiazines, quinidine, tricyclic antidepressants, and anticholinergics
Documented hypersensitivity; angle-closure glaucoma; stenosing peptic ulcers; prostatic hypertrophy or bladder neck obstructions; myasthenia gravis; pyloric or duodenal obstruction; achalasia (megaesophagus); megacolon
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May exacerbate hypertension, tachycardia, cardiac arrhythmias, liver or kidney disorders, hypotension, prostatic hypertrophy, urinary retention, and obstructive disease of GI/GU tracts; may cause toxic psychosis in psychiatric patients with extrapyramidal reactions resulting from phenothiazine
Diphenhydramine (Benadryl)
Although an antihistamine, also possesses significant anticholinergic properties. Mechanism of action is identical to that of benztropine.
Adult
50-100 mg IV/IM repeat prn
Pediatric
1-2 mg/kg IV/IM repeat prn
Potentiates effect of CNS depressants; alcohol content of syrup dosage form may cause disulfiramlike reaction in patients taking medications that can cause these reactions
Documented hypersensitivity; MAOIs; angle-closure glaucoma
Pregnancy
A - Fetal risk not revealed in controlled studies in humans
Precautions
May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction
Benzodiazepines
Normal balance between dopamine and acetylcholine in the basal ganglia involves modulation from GABA-containing striatonigral neurons. GABA-ergic neurons are inhibitory and antagonize excitatory dopaminergic neurons. GABA agonists (eg, benzodiazepines) may be helpful for acute dystonic reactions.
Diazepam (Valium)
Some recommend using for patients with dystonic reactions refractory to anticholinergic therapy or when such therapy is contraindicated.
Adult
2.5-10 mg IV slow push
Pediatric
0.1 mg/kg IV slow push repeat prn
Phenothiazines, barbiturates, alcohols, and MAOIs may increase CNS toxicity
Documented hypersensitivity; narrow-angle glaucoma
Pregnancy
X - Contraindicated; benefit does not outweigh risk
Precautions
Caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)
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| Overview: Toxicity, Medication-Induced Dystonic Reactions |
| Differential Diagnoses & Workup: Toxicity, Medication-Induced Dystonic Reactions |
 Treatment & Medication: Toxicity, Medication-Induced Dystonic Reactions |
| Follow-up: Toxicity, Medication-Induced Dystonic Reactions |
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References
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Piecuch S, Thomas U, Shah BR. Acute dystonic reactions that fail to respond to diphenhydramine: think of PCP. J Emerg Med. May-Jun 1999;17(3):527. [Medline].
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Further Reading
Keywords
medication-induced dystonic reactions, dystonic reaction, neuroleptic drug therapy, drug treatment, neuroleptics, neuroleptic agents, dyskinesia, acute dystonic reaction, neuroleptic drugs, involuntary muscle contractions
