Inbrija (Levodopa)

Inbrija, containing levodopa, acts on the dopaminergic pathway to manage Parkinson’s disease motor fluctuations.

• Parkinson’s disease (off episodes): provides rapid relief of motor symptoms during off periods.
• Parkinson’s disease (motor fluctuations): improves motor control when oral therapy is insufficient.
• Patients with oral levodopa intolerance: offers an inhaled alternative to achieve therapeutic plasma levels.

• Levodopa is absorbed through the pulmonary epithelium after inhalation and crosses the blood‑brain barrier, where aromatic L‑amino‑acid decarboxylase converts it to dopamine. The increased central dopamine compensates for the deficient endogenous production in Parkinson’s disease, thereby enhancing motor function and reducing off‑episode severity.

Inbrija may cause a range of adverse reactions, which are categorized by frequency.

Common Side Effects

• Cough: mild irritation of the throat after inhalation.
• Throat irritation: discomfort or soreness in the throat.
• Nausea: feeling of queasiness following dosing.
• Headache: mild to moderate head pain.
• Dizziness: transient light‑headedness.

Serious or Rare Side Effects

• Dyskinesia: involuntary, erratic movements.
• Orthostatic hypotension: sudden drop in blood pressure upon standing.
• Hallucinations: visual or auditory perceptual disturbances.
• Pulmonary edema: rare accumulation of fluid in the lungs.
• Severe allergic reaction: rash, swelling, or breathing difficulty.

Before prescribing Inbrija, clinicians should consider several safety measures.

• Assess motor fluctuations: confirm that off episodes are present and require rapid relief.
• Monitor for dyskinesia: watch for involuntary movements after initiation.
• Avoid in severe respiratory disease: patients with COPD or asthma may have increased risk.
• Use with caution alongside MAO‑B inhibitors: may potentiate dopaminergic effects.
• Store at room temperature: keep device in original packaging, protect from moisture and heat.

Levodopa inhalation can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Carbidopa: may increase levodopa availability and risk of dyskinesia; avoid concurrent high doses.
• MAO‑B inhibitors: risk of hypertensive crisis when combined with levodopa.
• Non‑selective MAO inhibitors: contraindicated due to severe pressor responses.

Moderate Interactions (Monitor Closely)

• Antipsychotics (dopamine antagonists): may reduce therapeutic effect of levodopa.
• Antiemetics such as metoclopramide: can diminish levodopa efficacy.
• Iron supplements: may decrease levodopa absorption; separate administration times.