ICD-10 Code G71.14 – Drug induced myotonia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G71.14 – Drug induced myotonia
What it is
Use this code for myotonia caused by a medication or other drug exposure. It describes delayed muscle relaxation that is attributed to a drug effect, not a primary inherited muscle disorder.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include stiffness, delayed release after contraction, and difficulty relaxing hand or facial muscles after use.
When to use this code
Use G71.14 when the provider documents myotonia as drug induced or medication related. It may apply when symptoms begin after starting a medication, or when the record clearly links the muscle stiffness to a drug exposure.
Do not infer causation from symptoms alone. If the chart does not identify the drug as the cause, check documentation before assigning this code.
Do not use for
Do not use this code for congenital or inherited myotonia, or for muscle stiffness with no documented drug cause. Check documentation.
Coding tip
Link the diagnosis to the offending drug only when the provider explicitly states the relationship.