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How long does it take for Inbrija to work?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on April 21, 2023.

Official answer


Key Points

  • Inbrija can start to relieve your OFF symptoms from Parkinson’s disease (such as tremor, slowed movement and difficulty walking) as soon as 10 minutes after you inhale your dose.
  • In clinical studies, a significant effect on OFF symptoms was seen at 30 minutes when compared to an inactive placebo.
  • The action of Inbrija in helping to control symptoms was also continued for one hour after the dose.

Inbrija SPAN-PD Study

In the 12-week, Phase 3 pivotal SPAN-PD trial, patients with Parkinson’s disease (PD) saw the onset of action of Inbrija as early as 10 minutes after receiving their dose (the earliest time point measured).

A total of 114 patients received Inbrija (levodopa inhalation) 84 mg (2 capsules for inhalation), and 112 patients received placebo. This study was conducted in several countries.

Doctors measured this outcome in SPAN-PD using a standard study tool known as the Unified Parkinson's Disease Rating Scale (UPDRS) Part III. UPDRS Part III is used to assess the severity of primary motor symptoms in patients with PD.

The clinical endpoint investigators were looking for was a “significant improvement in motor function at 30 minutes postdose” compared to an inactive placebo. This endpoint was reached and was statistically significant (P=0.009), meaning it did not happen just by chance.

This clinical effect was also continued for 60 minutes after the dose. A significantly greater proportion of patients with PD using Inbrija (58%) as compared to the group receiving the inactive placebo (36%) returned to an ON state and remained in the ON state for an hour after they took their dose (P=0.003).

Inbrija is absorbed into your bloodstream through the lungs and does not rely on absorption through the stomach.

When did the FDA approve Inbrija?

In December 2016, the FDA cleared Acorda Therapeutics’ Inbrija (levodopa), an oral, dry powder inhalation for the treatment of OFF episodes in people with Parkinson’s disease already taking a carbidopa/levodopa (common brand: Sinemet) regimen.

During OFF episodes, Parkinson’s disease symptoms such as tremor, slowed movement and difficulty walking return due to low dopamine levels that occur between the standard carbidopa/levodopa doses. OFF periods in Parkinson’s disease result from low levels of dopamine between doses of carbidopa/levodopa, are often unpredictable and appear more frequently over time.

Inbrija capsules contain a dry powder for inhalation only and are not to be swallowed or opened. Inbrija is used with a supplied inhaler. No more than 5 doses (10 capsules) of Inbrija should be used per day.

What common side effects can I expect with Inbrija?

Common side effects are:

  • cough (15% vs. 2% placebo)
  • upper respiratory tract infection (6% vs. 3% placebo)
  • nausea (5% vs. 3% placebo)
  • discolored sputum (5% vs. 0% placebo).
  • LeWitt PA, Hauser RA, Pahwa R, et al. Safety and efficacy of CVT-301 (levodopa inhalation powder) on motor function during off periods in patients with Parkinson's disease: a randomised, double-blind, placebo-controlled phase 3 trial. Lancet Neurol. 2019;18(2):145‐154. doi:10.1016/S1474-4422(18)30405-8

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