Drugs That Can Cause Parkinsonism

Parkinsonism is not a diagnosis, but rather a term used to describe a set of symptoms.[1] These include stiffness (rigidity), slowness of movement (bradykinesia) and shaking body parts (also referred to as resting tremor). These difficulties can result in problems with fine and gross motor skills, including getting dressed, writing by hand, trouble turning over in bed, difficulty with balance, and shuffling gait.

These symptoms are most commonly associated with Parkinson’s disease, a movement disorder that worsens over time and that is caused by the breakdown of neurons in the brain that produce the neurotransmitter dopamine.[2],[3]

The second most common reason for these symptoms is drug-induced parkinsonism, a movement disorder that mimics Parkinson’s disease but is caused by prescription-drug use that interferes with the transmission of dopamine in the brain.[4]

Other causes of parkinsonism, including dementia with Lewy bodies, cerebrovascular disease, head trauma and infections, are not discussed in this article.

About drug-induced parkinsonism

Drugs that commonly induce parkinsonism are first- and second-generation antipsychotics, prokinetics (gut motility agents), antinausea agents and, less commonly, selective serotonin reuptake inhibitor antidepressants and calcium channel blockers for high blood pressure.[5] Table 1 (below) shows examples of antipsychotics that may cause drug-induced parkinsonism. Table 2 (below) shows examples from other drug classes.

Drug-induced parkinsonism can be difficult to diagnose because the symptoms are almost indistinguishable from those of Parkinson’s disease.[6],[7] There can be slight differences, however. For instance, Parkinson’s disease often only affects one side of the body, whereas symptoms tend to be more symmetric in drug-induced parkinsonism. Moreover, patients with Parkinson’s disease, but not those with drug-induced parkinsonism, also typically have non-movement-related symptoms such as loss of smell, constipation, difficulty sleeping or depression.

Symptoms of drug-induced parkinsonism usually develop a few weeks or months after a person starts taking a new drug.[8] However, in some cases symptoms first develop a few years later. Generally, patients first notice body rigidity, slowed movements and resting tremors.

Drug-induced parkinsonism has been insufficiently studied, and there are no commonly accepted diagnostic criteria.[9] For this reason, drug-induced parkinsonism is frequently missed or misdiagnosed, and its symptoms are often attributed to Parkinson’s disease.[10] It also is not clear how many patients are affected, as studies show a wide range for the number of patients with parkinsonism symptoms who have drug-induced parkinsonism.[11] For at least 8% to 12% of patients with parkinsonism, symptoms may be caused by drug use.[12]

Older adults are at a higher risk of drug-induced parkinsonism, possibly because dopamine transport in the body decreases with age. Although the mechanism is not entirely understood, medications that block dopamine receptors in the brain or otherwise interfere with the transmission of dopamine may cause the symptoms.[13],[14]

Treatment

Although there is no effective treatment for drug-induced parkinsonism, decreasing the dose, switching to a different drug that is less likely to cause symptoms, or stopping the offending drug usually resolves the symptoms within a few days.[15] In some cases, however, symptoms only resolve several months after drug discontinuation.[16]

Especially for patients who may not be able to easily stop the drug that is likely responsible, additional diagnostics, such as targeted brain imaging, may help distinguish between drug-induced parkinsonism and Parkinson’s disease.[17] Table 1. Oral Antipsychotics That May Cause Drug-Induced Parkinsonism[18]

*Designated as Limited Use by Public Citizen’s Health Research Group
**Designated as Limited Use as an adjunctive treatment to antidepressants for major depressive disorder and Do Not Use for the treatment of Alzheimer’s disease-associated dementia by Public Citizen’s Health Research Group
***Combination with samidorphan; Do No Use because of concerns about opioid overdose

Table 2. Other Drug Classes That May Cause Drug-Induced Parkinsonism[19]

†Brand-name combination products that contain other active ingredients are not included.
*Designated as Limited Use by Public Citizen’s Health Research Group
**Nasal spray
***Rectal suppository

What You Can Do

If you or a loved one has recently been diagnosed with Parkinson’s disease or is experiencing symptoms of parkinsonism (such as rigidity, resting tremors or slowed movements) within a few weeks or months of starting a new drug or a dose increase, speak to your clinician to make sure they have considered drug-induced parkinsonism and that this is not the cause of your symptoms. Do not stop taking any drug without speaking to your clinician first.
 

References

[1] American Parkinson Disease Association. What is drug-induced parkinsonism. September 29, 2023. https://www.apdaparkinson.org/article/drug-induced-parkinsonism/. Accessed December 4, 2025.

[2] Mayo Clinic. Parkinson’s disease. https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055. Accessed December 4, 2025.

[3] Conn H, Jankovic J. Drug-induced parkinsonism: diagnosis and treatment. Expert Opin Drug Saf. 2024 Dec;23(12):1503-1513.

[4] Wyant KJ, Chou KL. Drug-induced parkinsonism. UpToDate. Updated May 21, 2025.

[5] Oh YS, Yoo SW, Lyoo CH, et al. Decreased thalamic monoamine availability in drug-induced parkinsonism. Sci Rep. 2022 Mar 8;12(1):3749.

[6] American Parkinson Disease Association. What is drug-induced parkinsonism? September 29, 2023. https://www.apdaparkinson.org/article/drug-induced-parkinsonism/. Accessed December 5, 2025.

[7] Wyant KJ, Chou KL. Drug-induced parkinsonism. UpToDate. Updated May 21, 2025.

[8] Ibid.

[9] Brigo F, Erro R, Marangi A, et al. Differentiating drug-induced parkinsonism from Parkinson's disease: an update on non-motor symptoms and investigations. Parkinsonism Relat Disord. 2014 Aug;20(8):808-814.

[10] Wyant KJ, Chou KL. Drug-induced parkinsonism. UpToDate. Updated May 21, 2025.

[11] de Germay S, Montastruc F, Carvajal A, et al. Drug-induced parkinsonism: Revisiting the epidemiology using the WHO pharmacovigilance database. Parkinsonism Relat Disord. 2020 Jan;70:55-59.

[12] Conn H, Jankovic J. Drug-induced parkinsonism: diagnosis and treatment. Expert Opin Drug Saf. 2024 Dec;23(12):1503-1513.

[13] Ibid.

[14] Wyant KJ, Chou KL. Drug-induced parkinsonism. UpToDate. Updated May 21, 2025.

[15] Ibid.

[16] Brigo F, Erro R, Marangi A, et al. Differentiating drug-induced parkinsonism from Parkinson's disease: an update on non-motor symptoms and investigations. Parkinsonism Relat Disord. 2014 Aug;20(8):808-814.

[17] Conn H, Jankovic J. Drug-induced parkinsonism: diagnosis and treatment. Expert Opin Drug Saf. 2024 Dec;23(12):1503-1513.

[18] Wyant KJ, Chou KL. Drug-induced parkinsonism. UpToDate. Updated May 21, 2025.

[19] Ibid.