Inbrija (levodopa inhalation powder) for Parkinson’s disease
Fact-checked by What is Inbrija for Parkinson’s disease?
Inbrija (levodopa inhalation powder) is an approved add-on therapy used to help manage off episodes — periods when symptoms fluctuate between regular doses of levodopa-based regimens — in people with Parkinson’s disease.
Parkinson’s is characterized by low levels of the signaling molecule dopamine due to the progressive death of the nerve cells that produce it, leading to various motor and nonmotor symptoms.
The mainstay of Parkinson’s treatment is oral levodopa, a precursor molecule that can be converted into dopamine to replenish low levels in the brain. It is often combined with carbidopa, a dopa-decarboxylase (DDC) inhibitor that helps more levodopa reach the brain. However, as the disease progresses, it can be more difficult to control symptoms with levodopa/carbidopa, leading to off episodes.
Inbrija is an inhaled formulation of levodopa that’s designed to quickly increase brain dopamine levels for rapid symptom control during an off episode. Because it bypasses the digestive tract, Inbrija works faster than oral forms of the medication, helping ease symptoms as early as 10 minutes after administration.
Merz Therapeutics, which acquired Inbrija’s original developer, Acorda Therapeutics, markets the therapy in the U.S.
Therapy snapshot
| Brand name | Inbrija |
| Chemical name | Levodopa |
| Usage | Used to treat off episodes in Parkinson’s patients on levodopa/carbidopa |
| Administration | Oral inhalation |
Who can take Inbrija?
In the U.S., Inbrija is approved for the treatment of off episodes in people with Parkinson’s disease who are using levodopa and carbidopa. It is also approved in the European Union for patients who are taking levodopa in combination with a DDC inhibitor.
The prescribing information for Inbrija notes that the medication is contraindicated, or should not be used, by people who are currently taking a nonspecific monoamine oxidase (MAO) inhibitor, a type of antidepressant medication, or who have used one in the last two weeks.
Inbrija is usually not recommended for people with major psychotic disorders or underlying chronic lung diseases.
How is Inbrija administered?
Inbrija is inhaled directly into the lungs using a handheld inhaler device. The medication comes as a dry powder in capsules that are inserted into the inhaler.
The standard Inbrija dosage is two 42 mg capsules (total of 84 mg), taken as needed for off episodes, up to five times daily. Patients should not administer more than one dose of Inbrija for a single off episode.
Inbrija capsules should only be used with the provided inhaler — they should never be swallowed. A healthcare professional can provide detailed Inbrija inhaler instructions. It’s important to understand how to use the Inbrija inhaler properly for the medication to be effective.
Inbrija in clinical trials
Inbrija’s U.S. approval was supported by two Phase 3 trials, which collectively involved more than 750 people with Parkinson’s who were experiencing at least two hours of daily off time despite ongoing carbidopa-levodopa therapy.
- SPAN-PD (NCT02240030) tested two doses of Inbrija against a placebo, used as needed to control off episodes over 12 weeks (about three months). At week 12, participants underwent an in-clinic assessment during an off episode and again 30 minutes after taking their assigned dose of Inbrija or a placebo. Inbrija at its now-approved dose significantly reduced motor symptom severity compared with the placebo, and more people on Inbrija achieved sustained symptom control for at least an hour (58% vs. 36%).
- CT-301-005 (NCT02352363) was an open-label study in which participants either continued on their standard oral therapy regimen or added Inbrija at its approved dose as needed for off episodes. Most measures of respiratory function were similar between the groups, suggesting the inhaled medication was safe for the respiratory system. Within an hour of inhaling the therapy, 80% to 85% of Inbrija participants experienced a resolution of their off episodes, and daily off time decreased, on average, by more than an hour.
A one-year extension (NCT02242487) that included some participants from previous clinical trials showed that the average daily off time decreased with Inbrija and the treatment was overall well tolerated.
Inbrija side effects
The most common side effects associated with Inbrija are:
- cough
- nausea
- upper respiratory tract infection
- discoloration in secretions coughed up from the lungs
Less common, but potentially serious safety concerns that may arise when using Inbrija include:
- excessive drowsiness or falling asleep during everyday activities
- new or worsening hallucinations and psychotic-like behavior
- problems with impulse control or strong compulsions while using Inbrija
- new or worsening dyskinesia, or sudden, involuntary movements
- increased pressure in the eye for people with glaucoma, a type of eye disease
- airway tightening for people with underlying chronic lung diseases
- abnormal lab test results, including markers of liver, kidney, and red blood cell health
Individuals will be monitored for these side effects and may need to lower their Inbrija dose or discontinue treatment entirely if they occur. Patients should never suddenly stop using Inbrija without consulting their doctor, as this can trigger potentially serious withdrawal symptoms, including high fever and confusion.
Patients should tell their doctors about all medications they are using. People taking Inbrija with MAO-B inhibitors, which are sometimes prescribed for Parkinson’s, may need to be monitored for blood pressure changes.
Parkinson's News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
