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How long does it take for Ongentys to work?

Medically reviewed by Philip Thornton, DipPharm. Last updated on Sep 13, 2023.

Official answer

  • Ongentys starts working within one week of starting treatment
  • The full effects of Ongentys are seen within two to three weeks of starting treatment

Ongentys (opicapone) starts working quickly. Results from two large phase III trials showed that within one week of starting treatment with Ongentys it started working and significantly decreased mean off-time by 61 min for those receiving Ongentys 25 mg daily and 75 min for those receiving Ongentys 50 mg daily, compared with 23 min for those receiving placebo (p=0.0013, P<0.0001, respectively).

Further improvements were observed during the second and third week of treatment, after which the treatment effect stabilized. At the end of the 14-15 week study, a significant decrease in off-time of 93 min for Ongentys 25 mg recipients and 120 min of Ongentys 50 mg recipients was observed, compared with a 55 min decrease for placebo recipients (p=0.0091, p<0.001, respectively).

Ongentys is taken once daily at bedtime and is used to help people with Parkinson’s disease who are experiencing ‘off’ episodes (periods of time when their symptoms recur) while being treated with levodopa/carbidopa. It’s a COMT (catechol-O-methyltransferase) inhibitor, which helps to prevent off episodes by increasing the amount of levodopa that reaches the brain by blocking the COMT enzyme, which breaks down levodopa in the blood.


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