ICD-10 Code G21.1 – Other drug-induced secondary parkinsonism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G21.1 – Other drug-induced secondary parkinsonism
What it is
This code identifies parkinsonism caused by medication or other drugs, rather than idiopathic Parkinson disease. It covers secondary movement symptoms that begin after exposure to a causative drug.
Clinical signs
Common findings include bradykinesia, rigidity, tremor, and slowed movements. Clinical features vary; refer to documentation for the suspected drug relationship and whether symptoms are symmetric or persistent.
When to use this code
Use G21.1 when the record clearly links parkinsonian symptoms to a medication or other drug exposure. It is appropriate when the provider documents drug-induced parkinsonism, secondary parkinsonism, or a similar causal statement. Check documentation if the specific agent is not named.
Do not use for
Do not use this code for idiopathic Parkinson disease or for parkinsonism without a documented drug cause. If the chart describes another specified secondary parkinsonism, use the more specific code instead.
Coding tip
Code the causal drug exposure when documented, and verify that the provider explicitly connects it to the parkinsonism.