Levodopa: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on June 20, 2023.

1. How it works

• Levodopa is available as an inhalation that may be used to treat intermittent OFF episodes in people with Parkinson's disease (PD). An OFF period describes a return of PD symptoms between regular doses of levodopa/carbidopa.
• Research has shown that symptoms of Parkinson's disease are associated with the depletion of dopamine in the brain. Administering dopamine to treat Parkinson's disease is ineffective because it does not cross the blood-brain barrier. But levodopa, a precursor of dopamine, does cross the blood-brain barrier and appears to be converted to dopamine in the brain. Administering levodopa inhalation increases levels of dopamine in the brain which helps to relieve the symptoms of Parkinson's disease.
• Levodopa inhalation belongs to the class of medicines known as dopaminergic antiparkinsonian agents. It may also be called a dopamine antiparkinsonian agent or a dopamine agonist.

2. Upsides

• May be used to treat intermittent OFF episodes in people with Parkinson's disease who are already being treated with carbidopa/levodopa.
• Because levodopa is an inhalation, it is rapidly absorbed and has a quick onset of effect.
• One of the few formulations that only contains levodopa. Oral formulations of levodopa are almost always combined with carbidopa, because carbidopa prevents levodopa from being broken down in the body, which allows more to reach the brain, reducing side effects such as nausea and vomiting.
• Effective at relieving symptoms such as slowness, stiffness, or rigidity due to declining plasma levodopa levels in patients with PD. In some cases levodopa may treat PD tremors as well.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Cough, upper respiratory tract infection, nausea, and discolored sputum are the most common side effects reported.
• Hallucinations have been reported in less than 2% of people prescribed levodopa inhalation. These may be accompanied by confusion, insomnia, and excessive dreaming. Intense urges such as an urge to gamble, have sex, spend money, or binge eat have also been reported by people taking levodopa inhalation. Dyskinesias (involuntary movements) may be exacerbated.
• Levodopa inhalation is expensive and costs around $1,000 for a supply of 60 capsules. However, most people do not pay this price. Private or government insurance, online discount coupons, manufacturer copay assistance, and patient assistance programs can all lower the price.
• May only be available from a Specialty Pharmacy.
• Not suitable for patients with asthma, COPD, or other chronic underlying lung diseases because of the risk of bronchospasm. There is a risk of exacerbating psychosis in people with psychotic disorder and levodopa inhalation may increase intraocular pressure in those with glaucoma.
• Abnormalities in laboratory tests, such as alkaline phosphatase, AST, ALT, lactic dehydrogenase, bilirubin, blood urea nitrogen, and a positive direct antibody test have been reported. May cause hemolytic anemia. Levodopa preparations increase levels of catecholamines and their metabolites in the plasma and urine and false-positive results suggesting pheochromocytoma have been reported.
• May cause drowsiness in some people and affect their ability to drive or operate machinery. Other medications that cause drowsiness (for example, sleep medicines, antidepressants, or antipsychotics) may worsen this effect.
• Do not use it within 2 weeks of a nonselective monoamine oxidase inhibitor such as phenelzine or tranylcypromine because it may cause extremely high blood pressure.
• Discontinuation or dose reduction of levodopa has been associated with a symptom complex that resembles neuroleptic malignant syndrome. Symptoms include fever, hyperthermia, muscle rigidity, involuntary movements, altered consciousness, confusion, fast heartbeat, or sweating.
• There is a lack of data regarding the effects of levodopa inhalation during pregnancy or while breastfeeding.
• Not available as a generic. Available under the brand name Inbrija.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Levodopa inhalation is an inhaled levodopa preparation that may be used to decrease symptoms of slowness, stiffness, or rigidity due to declining plasma levodopa levels in patients with Parkinson's Disease (also known as OFF symptoms). Cough and upper respiratory tract infections are the main side effects reported and it may interact with supplements such as iron salts, vitamin B6 (pyridoxine), and multivitamins.

5. Tips

• Use levodopa inhalation when your Parkinson's symptoms start to return (this is often called the OFF period and it tends to happen before your next regular dose of levodopa/carbidopa).
• Levodopa inhalation is available as capsules that are inserted into the inhalation device. DO NOT swallow levodopa inhalation capsules. Only use levodopa inhalation capsules with the levodopa inhalation inhaler. The recommended dose of levodopa inhalation is two 42 mg capsules (84 mg), administered separately, as needed via the inhaler, up to 5 times a day. Ask your doctor, pharmacist, or nurse to show you how to use the levodopa inhaler if you are not sure.
• When you inhale levodopa inhalation, it may cause a sensation of coughing or choking at the time of administration. Drinking a glass of water may help with this.
• DO NOT swallow or open the levodopa inhalation capsules. Keep them in their sealed blister package and remove each one just before you use it. Do not use any capsule that looks crushed, damaged, or wet.
• Remove the blue cap from the inhaler. Twist off the white mouthpiece. Load 1 capsule into the capsule chamber of the inhaler. Do not load 2 capsules at the same time. You will do 2 separate inhalations (with one capsule per inhalation) to get your full dose. Attach the mouthpiece until you hear a click. The inhaler is breath-actuated so it does not need to be pressed to activate the inhalation.
• Breathe out fully to get as much air out of your lungs as possible. Put the mouthpiece just in front of your mouth and breathe in (inhale) deeply. If you did not hear or feel the capsule “whirl” (spin) while inhaling, you may need to take a deeper breath. If you cough or stop your dose, repeat this step using the same capsule. Hold your breath for about 5 to 10 seconds, then slowly breathe out.
• Twist and pull off the mouthpiece. Remove the used capsule, then load a second capsule into the inhaler. Repeat the same steps. You may use a dry cotton swab or tissue to clean the mouthpiece. Put the cap back on after you are done with your dose.
• Levodopa inhalation may cause drowsiness and there have been reports of people falling asleep while engaged in activities of daily living, including driving a car. Some people reported drowsiness, and others reported no warning signs and believed they were alert immediately before the event. Some of these events were reported more than 1 year after the initiation of treatment. Other medications that cause drowsiness (for example, sleep medicines, antidepressants, or antipsychotics) may worsen this effect. Talk to your doctor if you experience drowsiness that may affect your ability to drive or episodes of falling asleep during activities.
• Tell your doctor if you experience abnormal involuntary movements or have movements that become worse while taking levodopa inhalation.
• Be careful when going from sitting or lying down to standing because levodopa inhalation may cause your blood pressure to drop and you may develop symptoms such as dizziness, nausea, or sweating. Rise slowly.
• Levodopa inhalation may affect your impulse control and you may experience intense urges to gamble, spend money, eat, or have sex. Tell your doctor if this happens to you because a dosage reduction may decrease these urges.
• Store the inhaler and capsules in a dry place at room temperature (68°F to 77°F [20°C to 25°C]). Do not freeze or refrigerate levodopa inhalation. Do not store capsules in the inhaler for a future dose. Throw out the inhaler after all capsules in the carton have been used. Use the new inhaler that comes with your prescription refill. Keep out of reach of children.
• If you are experiencing a lot of OFF symptoms, you may benefit from a protein redistribution diet. Before changing to a protein redistribution diet should be discussed with your doctor. Studies have also shown that a good diet containing a high amount of fruit, vegetables, and fish reduces the risk of PD and may slow its progression.
• Talk to your doctor or pharmacist before taking any other medications or supplements with levodopa inhalation because they may not be compatible. This includes multivitamins, iron, and vitamin B6 supplements.
• Levodopa inhalation may turn your body fluids (your urine, sputum, saliva, or sweat) a dark color.
• If you have any questions about levodopa inhalation, brand name Inbrija, you can call Acorda’s Prescription Support Services at 1-888-887-3447, 8 am to 8 pm Eastern time, Monday through Friday.
• Tell your doctor if you are pregnant or intend to become pregnant before starting levodopa inhalation because it may not be compatible with pregnancy or breastfeeding.

6. Response and effectiveness

• Starts to work within 10 minutes of inhaling a dose. Research has shown levodopa inhalation is significantly more effective than a placebo at relieving OFF symptoms at 30 minutes. This effect continued for one hour after the dose.
• Absorbed into the bloodstream through the lungs and does not rely on absorption through the stomach.
• Levodopa inhalation does not slow or reduce the progression of Parkinson’s disease.

7. Interactions

Medicines that interact with levodopa inhalation may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with levodopa inhalation. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with levodopa inhalation include:

• 5-hydroxytryptophan
• amisulpride
• antidepressants, such as tricyclic antidepressants (eg, amitriptyline) or monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine)
• any medication that lowers blood pressure, such as beta-blockers (eg, atenolol or sotalol), ACE inhibitors (such as captopril or enalapril), or diuretics (such as bendrofluazide or furosemide
• any medication that may cause drowsiness, such as benzodiazepines (eg, diazepam, lorazepam), first-generation antihistamines (such as doxylamine or promethazine), or opioids (such as codeine, morphine)
• cholesterol-lowering agents such as atorvastatin or simvastatin
• dopamine D2 receptor antagonists such as butyrophenones, phenothiazines, or thioxanthenes and atypical antipsychotics (eg, olanzapine, quetiapine, risperidone, ziprasidone)
• dopamine-depleting agents, such as reserpine or tetrabenazine
• iron salts or multivitamins that contain iron (can chelate with levodopa reducing its absorption)
• metoclopramide (has dopamine antagonistic properties)
• pyridoxine (vitamin B6) (may decrease effectiveness)
• selegiline
• sodium oxybate
• vincristine.

Avoid drinking alcohol or taking illegal or recreational drugs while taking levodopa inhalation.

Some foods have high levels of vitamin B6, such as fish, avocados, bananas, beef, cabbage, carrots, cauliflower, chicken, hazelnuts, peanuts, pork, sweetcorn, and walnuts. Ask your doctor if you need to limit your intake of these foods.

Do not take levodopa inhalation within 2 weeks of a nonselective monoamine oxidase inhibitor such as phenelzine or tranylcypromine because it may cause extremely high blood pressure.

Note that this list is not all-inclusive and includes only common medications that may interact with levodopa inhalation. You should refer to the prescribing information for levodopa inhalation for a complete list of interactions.

References

• Levodopa (Inhalation) Updated 01/2023. Drugs.com. https://www.drugs.com/cons/levodopa-inhalation.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use levodopa only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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