Products
Levodopa for inhalation was approved in the United States in 2018 and in the EU in 2019 (Inbrija, capsules containing a powder for inhalation).
Structure and properties
Levodopa (C9H11NO4, Mr = 197.2 g/mol) exists as a white crystalline powder that is sparingly soluble in water. It is a derivative of the amino acid tyrosine.
Effects
Levodopa is a prodrug of the neurotransmitter dopamine and is activated in the central nervous system by decarboxylation. Inhaled administration has the advantage over peroral administration in that the drug enters the bloodstream rapidly and bypasses first-pass metabolism.
Indications
For intermittent treatment of OFF episodes in patients with Parkinson’s disease who are pretreated with levodopa and a decarboxylase inhibitor.
Dosage
According to the SmPC. The capsules are inhaled as needed. They must not be ingested.
Contraindications
- Hypersensitivity
- Treatment with an MAO inhibitor
For complete precautions, see the drug label.
Interactions
Drug-drug interactions have been described with MAO inhibitors, dopamine antagonists, and iron salts.
Adverse effects
The most common possible adverse effects include cough, nausea, upper respiratory tract infection, and discolored sputum.