What drugs are known to cause dystonia?

October 11, 2025 •

4 min read

According to a study reported in Clinical and Experimental Emergency Medicine, gastrointestinal medications were the most common cause of drug-induced dystonia (DID) in children, accounting for 57% of cases. Drug-induced dystonia is a movement disorder caused by certain medications, characterized by involuntary and sustained muscle contractions that lead to twisting and repetitive movements or abnormal postures.

Quick Summary

A variety of medications, most notably antipsychotics and antiemetics, can disrupt the brain's dopamine-acetylcholine balance and trigger dystonia. These drug-induced reactions manifest as either acute or tardive dystonia, with varying onset times and potential for permanence.

Key Points

Dopamine-Blocking Agents: Antipsychotics and antiemetics are the most common classes of drugs known to cause dystonia by blocking dopamine receptors in the brain.
Acute vs. Tardive Dystonia: Drug-induced dystonia can occur acutely (within hours to days) or as a tardive syndrome (after months or years of use), with varying implications for permanence.
Antipsychotics: Older first-generation antipsychotics like haloperidol carry a high risk, while newer atypical agents have a lower, but still present, risk of causing dystonia.
Antiemetics: Nausea medications such as metoclopramide and prochlorperazine are significant causes of acute dystonic reactions.
Management: The primary treatment involves discontinuing the offending drug, with acute cases often responding to anticholinergic medications like benztropine or diphenhydramine.
Risk Factors: Young age, male gender, high-potency drugs, and rapid dose changes increase the risk of acute dystonia, while older age and prolonged use are risk factors for tardive forms.
Other Drug Culprits: Antidepressants (SSRIs), some calcium channel blockers, and certain anticonvulsants have also been linked to drug-induced dystonia.

The role of dopamine imbalance in drug-induced dystonia

Dystonia is a movement disorder that arises when the delicate balance of neurotransmitters, particularly dopamine and acetylcholine, in the basal ganglia of the brain is disturbed. Medications that block dopamine receptors, known as dopamine receptor antagonists, are the most common culprits. This blockage leads to an excess of acetylcholine activity, resulting in the involuntary muscle contractions characteristic of dystonia. The reaction can occur shortly after beginning a medication, known as acute dystonia, or after months or years of use, termed tardive dystonia.

Antipsychotic medications

Antipsychotics, especially older 'first-generation' or 'typical' antipsychotics, are well-established causes of drug-induced dystonia due to their strong dopamine-blocking properties. The risk is generally higher with high-potency agents and in younger patients. While newer 'second-generation' or 'atypical' antipsychotics have a lower risk, they are not without potential.

First-generation antipsychotics

These drugs bind strongly to dopamine D2 receptors, making them more likely to cause extrapyramidal symptoms, including acute and tardive dystonia.

Haloperidol (Haldol): A high-potency antipsychotic with a well-known risk for acute dystonic reactions, particularly in young men.
Fluphenazine: A potent dopamine blocker linked to a higher incidence of extrapyramidal side effects.
Chlorpromazine (Thorazine): An older antipsychotic known to cause both acute and tardive dystonia.
Trifluoperazine: Another first-generation agent implicated in causing both types of drug-induced dystonia.

Second-generation antipsychotics

While considered safer in terms of movement disorders, they still carry a risk, especially with higher doses or prolonged use.

Risperidone (Risperdal): The incidence of dystonia is lower but still a potential side effect, especially at higher doses.
Olanzapine (Zyprexa): This atypical antipsychotic has a lower risk profile for acute dystonia, though cases have been reported.
Quetiapine (Seroquel): This drug has a weak affinity for dopamine receptors, resulting in a low risk of extrapyramidal side effects.

Antiemetic medications

Several anti-nausea medications act by blocking dopamine receptors, making them significant causes of dystonic reactions, especially acutely.

Metoclopramide (Reglan): This is a well-documented cause of both acute and tardive dystonia, and the risk is higher in younger individuals and with increased dosage.
Prochlorperazine (Compazine): Another dopamine-blocking antiemetic that is a common cause of acute dystonic reactions.
Promethazine (Phenergan): An antiemetic with antihistamine properties that is also known to cause dystonia.

Other drug classes that cause dystonia

Beyond antipsychotics and antiemetics, several other types of medications can lead to dystonia.

Antidepressants: Selective serotonin reuptake inhibitors (SSRIs) have been associated with dystonia, particularly in older patients. Examples include sertraline (Zoloft) and fluoxetine (Prozac).
Calcium channel blockers: Certain calcium channel blockers, such as flunarizine and cinnarizine (not available in the US), have been linked to extrapyramidal symptoms, including tardive dystonia.
Anticonvulsants: Some anticonvulsant medications, like phenytoin, can be a cause of drug-induced dystonia.
Illicit drugs: Cocaine and other stimulants can increase the risk of dystonic reactions, especially in individuals taking other neuroleptic agents.

Comparison of acute vs. tardive dystonia


Feature	Acute Dystonia	Tardive Dystonia
Onset	Occurs within hours to days of starting a new medication or increasing a dose.	Occurs after prolonged exposure (months to years) to dopamine-blocking drugs.
Mechanism	Caused by an immediate, strong blockade of dopamine D2 receptors.	Believed to be caused by dopamine receptor hypersensitivity after long-term receptor blockade.
Risk Factors	Younger age, male gender, high-potency drugs, rapid dose changes, and previous dystonic episodes increase risk.	Older age, female gender, higher doses, and longer duration of treatment are risk factors.
Reversibility	Often reversible with discontinuation of the offending drug and administration of anticholinergic medication.	Potentially irreversible and may persist even after the causative drug is stopped.
Presentation	Often presents as an oculogyric crisis (upward eye deviation), torticollis (neck twisting), or laryngeal spasm.	Symptoms are often more localized and may be accompanied by other tardive syndromes.

Clinical approach and management

When a patient experiences dystonia, a detailed medication history is crucial for diagnosis. The first and most critical step is to discontinue the suspected causative drug, if medically appropriate. For acute dystonic reactions, immediate treatment with an anticholinergic medication, such as diphenhydramine or benztropine, is often effective. These medications help restore the dopamine-acetylcholine balance in the brain.

For chronic or tardive dystonia, management is more complex. Simply discontinuing the drug might not fully resolve symptoms, which can sometimes worsen during withdrawal. Treatment strategies may include switching to an atypical antipsychotic with a lower risk profile or using medications specifically approved to treat tardive dyskinesia, such as valbenazine. In severe, persistent cases, advanced treatments like botulinum toxin injections or deep brain stimulation (DBS) might be considered.

Conclusion

While a wide range of medications can cause dystonia, antipsychotics and antiemetics are the most frequent culprits due to their dopamine-blocking effects. The specific type of dystonia, whether acute or tardive, depends on the duration of drug exposure. Acute reactions are often reversible, especially with prompt treatment, while tardive forms can be more persistent and challenging to manage. Knowledge of which drugs are known to cause dystonia is essential for clinicians to ensure timely diagnosis and appropriate treatment, ultimately improving patient outcomes and quality of life. For more in-depth information, the Dystonia Medical Research Foundation offers comprehensive resources on drug-induced movement disorders.

Frequently Asked Questions

The primary cause is the disruption of the neurotransmitter balance in the brain, particularly involving dopamine and acetylcholine. Many medications, especially antipsychotics and antiemetics, block dopamine receptors, leading to an excess of acetylcholine and resulting in involuntary muscle contractions.

Older, first-generation (typical) antipsychotics, such as haloperidol and fluphenazine, are most likely to cause dystonia due to their strong dopamine-blocking effects. Newer, atypical antipsychotics have a lower risk, but it is still a potential side effect.

Yes, several anti-nausea (antiemetic) medications, including metoclopramide and prochlorperazine, are common causes of acute dystonic reactions because they also block dopamine receptors in the brain.

Acute dystonia occurs within hours or days of starting a drug, while tardive dystonia develops after prolonged exposure (months to years). Acute dystonia is often reversible, but tardive dystonia may be permanent.

Yes, other drug classes include certain antidepressants (SSRIs), specific calcium channel blockers, and some anticonvulsants. Illicit drugs like cocaine can also increase the risk.

For acute dystonia, treatment involves discontinuing the causative drug and administering anticholinergic agents like diphenhydramine or benztropine. For tardive dystonia, treatment is more complex and may involve switching medications or advanced therapies.

Risk factors for acute dystonia include young age, male gender, and high-potency drugs. For tardive dystonia, older age, female gender, and prolonged drug exposure are risk factors.