What is the most common side effect of levodopa? Understanding Nausea, Dizziness, and Dyskinesia

October 10, 2025 •

3 min read

Over one million people in the U.S. have Parkinson's disease, many of whom rely on levodopa to manage their symptoms. For those starting treatment, a key question arises: what is the most common side effect of levodopa? The answer depends on the phase of treatment, but it frequently involves short-term issues like nausea and dizziness or long-term motor complications such as dyskinesia.

Quick Summary

The most common side effects of levodopa are initial nausea and dizziness, often managed by combining it with carbidopa, and later-stage involuntary movements known as dyskinesia, which are associated with long-term use.

Key Points

Initial Nausea and Dizziness: In the early stages of levodopa treatment, nausea and dizziness (orthostatic hypotension) are very common side effects.
Role of Carbidopa: Carbidopa is combined with levodopa to reduce the nausea and vomiting caused by levodopa alone by preventing its peripheral breakdown.
Long-term Dyskinesia: Dyskinesia, or involuntary movements, is the most common and disabling long-term motor complication associated with extended levodopa use.
Managing Initial Side Effects: Eating a low-protein snack with medication and rising slowly from seated or lying positions can help alleviate nausea and dizziness.
Managing Long-term Dyskinesia: Strategies for dyskinesia include adjusting the dose, using extended-release formulations, or adding other medications like amantadine.
Importance of Medical Supervision: Dosage adjustments and managing side effects require close supervision by a healthcare professional to balance symptom control with adverse effects.
Orthostatic Hypotension Management: In addition to rising slowly, staying well-hydrated can reduce the incidence of dizziness caused by low blood pressure.

Levodopa is the most effective medication for managing the motor symptoms of Parkinson's disease (PD). It is converted to dopamine in the brain, helping to alleviate the dopamine deficiency in PD patients. To enhance its effectiveness and reduce certain side effects, levodopa is almost always prescribed with carbidopa. Being aware of potential side effects is important for managing treatment and maintaining quality of life.

The Most Common Early-Stage Side Effects

In the initial stages of treatment, patients often experience non-motor side effects that typically improve over time. The most frequent include nausea, dizziness, and fatigue.

Nausea and Vomiting

Nausea and vomiting are common, particularly when levodopa is taken without carbidopa. Carbidopa helps reduce these issues by preventing levodopa from converting to dopamine outside the brain. To manage nausea, even with carbidopa:

Take the medication with a low-protein snack or juice.
Drink plenty of water.
Start with a low dose and increase gradually under medical supervision.

Dizziness and Orthostatic Hypotension

Another common early side effect is dizziness or lightheadedness, often due to orthostatic hypotension (a drop in blood pressure when standing). To minimize this:

Rise slowly from sitting or lying down.
Stay well-hydrated.
Avoid hot baths or showers.

The Most Common Long-Term Side Effect: Dyskinesia

While initial side effects are often temporary, long-term levodopa use is frequently linked to motor complications, most notably dyskinesia.

What is Dyskinesia?

Dyskinesia involves involuntary, unpredictable movements of the trunk, limbs, or face, such as writhing or fidgeting. This differs from Parkinson's tremor and usually occurs when dopamine levels are highest after a dose.

Risk Factors and Development

Factors increasing the risk of dyskinesia include the duration and dosage of levodopa therapy, and the age at PD onset. It's thought to be related to the brain's fluctuating response to dopamine as the disease progresses.

Managing Levodopa Side Effects

Managing side effects requires working closely with a healthcare provider. Strategies include:

Dose Adjustment: Doctors may adjust the dose or frequency to balance symptom control and side effects.
Modified Formulations: Extended-release versions, like Rytary, provide more stable dopamine levels, potentially reducing dyskinesia.
Dietary Adjustments: Taking medication 30-60 minutes before or after high-protein meals can improve absorption.
Addressing Nausea: Supplemental carbidopa (Lodosyn) or anti-nausea medications may be prescribed for persistent nausea. Ginger tea can also help.
Managing Dyskinesia: Amantadine may be prescribed for bothersome dyskinesia. Deep brain stimulation (DBS) is a surgical option for advanced cases.

Comparison of Levodopa Side Effects


Side Effect Category	Common Early-Stage Effects	Common Long-Term Effects
Common Symptoms	Nausea, vomiting, dizziness, loss of appetite, somnolence, confusion	Involuntary movements (dyskinesia), motor fluctuations (wearing off), hallucinations, impulse control issues
Cause	Primarily due to levodopa being converted to dopamine peripherally before reaching the brain.	Fluctuations in dopamine levels caused by the long-term, non-continuous stimulation of brain receptors.
Onset	Occurs when initiating or increasing dosage.	Develops after years of treatment, especially with high doses or in younger-onset patients.
Management	Taking medication with food, rising slowly, dose titration, or supplemental carbidopa.	Dose adjustment, extended-release formulations, amantadine, or DBS.

Conclusion

Levodopa is vital for managing Parkinson's symptoms, but its side effects change over time. Early on, nausea and dizziness are common but often managed with carbidopa and proper administration. Dyskinesia is the main long-term complication, linked to fluctuating dopamine levels. Managing these effects is a personalized process involving dose adjustments, dietary considerations, and exploring different formulations or therapies with a healthcare provider. The goal is to balance improved mobility with potential side effects. For further support, the Parkinson's Foundation offers valuable resources.

Frequently Asked Questions

Nausea from levodopa is often managed by taking the medication in a combination with carbidopa. For persistent nausea, taking the medication with a low-protein snack, using supplemental carbidopa, or taking anti-nausea medication as directed by a doctor may be necessary.

Dyskinesia refers to involuntary, uncontrolled, and rapid movements of the face, trunk, and limbs that can occur with long-term levodopa therapy. It is thought to be caused by the fluctuations in dopamine levels that happen over the course of the day, particularly as Parkinson's disease progresses.

Yes, dyskinesia can be managed through several strategies, including adjusting the levodopa dosage, changing to an extended-release formulation for more stable dopamine levels, or adding other medications like amantadine.

Orthostatic hypotension is a sudden drop in blood pressure that occurs when a person stands up, leading to dizziness or lightheadedness. It is a common cardiovascular side effect of levodopa, especially when treatment begins.

Yes, older adults can be more sensitive to the central nervous system effects of levodopa, which may increase the risk of side effects like confusion, hallucinations, and dyskinesia. Dosages are often adjusted carefully for this population.

Yes, diet can affect levodopa absorption and, therefore, its side effects. High-protein foods can interfere with the drug's absorption, and some patients find that taking levodopa apart from high-protein meals can reduce motor fluctuations and improve effectiveness.

Less common side effects can include insomnia, vivid dreams or nightmares, changes in mood or behavior, and impulse control issues. In rare cases, more serious side effects like stomach bleeding or irregular heartbeat can occur.