Ongentys: Side effects, dosage, uses, and more

What is Ongentys (opicapone)?

Ongentys is a prescription medication used with carbidopa/levodopa in adults with Parkinson’s disease who
experience OFF episodes. It belongs to a drug class called COMT inhibitors
(catechol-O-methyltransferase inhibitors).

COMT is an enzyme that helps break down levodopa in the body. By inhibiting COMT, opicapone can increase and extend levodopa’s availability,
which may reduce daily OFF time and help smooth out end-of-dose wearing off. Think of it as “protecting” levodopa on its way to do its job.

What Ongentys is (and isn’t)

• It is an add-on therapy for people already taking carbidopa/levodopa who still have OFF time.
• It is not a rescue medication for sudden OFF episodes in the moment.
• It is not a replacement for levodopalevodopa still does the heavy lifting.

Uses: what Ongentys treats

Ongentys is indicated as an adjunctive treatment to carbidopa/levodopa for adults with Parkinson’s disease experiencing OFF episodes.
In everyday language: it’s used to help with end-of-dose wearing offwhen stiffness, slowness, tremor, or walking issues reappear
as a levodopa dose fades.

A practical example

Imagine someone takes carbidopa/levodopa at 8 a.m., noon, and 4 p.m. For the first few hours after each dose, symptoms improve (“ON” time).
But around 11 a.m. and 3 p.m., symptoms start returning early. Ongentys is taken once daily (usually at bedtime) to help reduce those gaps.

How well does Ongentys work?

Clinical studies in people with Parkinson’s disease taking stable carbidopa/levodopa used patient diaries to measure OFF time.
In two key trials, adding Ongentys 50 mg reduced average daily OFF time more than placebo.

What the numbers mean (in plain English)

• In one study, OFF time decreased by about 1.95 hours with Ongentys versus 0.93 hours with placebo,
  for a placebo-subtracted difference of ~1.01 hours (about 60 minutes).
• In another study, OFF time decreased by about 1.98 hours with Ongentys versus 1.07 hours with placebo,
  for a difference of ~0.91 hours (about 55 minutes).

Translation: many people get roughly an extra hour a day of reduced OFF time on average, though individual results vary.
Some may notice more benefit, some lessParkinson’s has never been big on uniformity.

Dosage and how to take Ongentys

Ongentys is taken by mouth once daily at bedtime. The typical adult dose is 50 mg.
There is also a 25 mg capsule strength used in certain situations (more below).

Timing matters: take it without food around the dose

Food can reduce absorption. The prescribing instructions generally advise:
do not eat for 1 hour before and for at least 1 hour after taking Ongentys. If this sounds like a small
scheduling puzzle, you’re not alonemany people build it into their bedtime routine.

Missed dose

If you miss a dose, skip it and take your next dose at the usual time the next day. Don’t double up to “catch up.”

Dosage adjustments in liver or kidney problems

• Moderate hepatic impairment (Child-Pugh B): a reduced dose of 25 mg once daily may be recommended.
• Severe hepatic impairment (Child-Pugh C): avoid use.
• End-stage renal disease (very low kidney function): avoid use.
• Severe renal impairment: no routine dose change, but closer monitoring may be recommended.

Do not stop suddenly without guidance

If Ongentys is discontinued, clinicians may monitor closely and adjust other Parkinson’s medications as needed.
Sudden medication changes in dopaminergic therapy can be associated with serious withdrawal-type symptoms such as fever, confusion, and severe muscle stiffness.

Side effects

Because Ongentys increases levodopa exposure, many side effects look like “more dopamine effects.”
The most common issues are often manageable, but some can be serious and should be addressed quickly.

Most common side effects (seen more than placebo)

In pooled clinical trials, the most common adverse reactions (roughly 4% or more and greater than placebo) included:
dyskinesia (uncontrolled movements), constipation, increased blood creatine kinase,
hypotension/syncope (low blood pressure or fainting), and weight loss.

Common side effects with approximate rates

• Dyskinesia: about 20% (vs ~6% with placebo)
• Constipation: about 6% (vs ~2%)
• Blood creatine kinase increased: about 5% (vs ~2%)
• Hypotension/syncope: about 5% (vs ~1%)
• Weight decreased: about 4% (vs ~0%)
• Dizziness: about 3% (vs ~1%)
• Dry mouth: about 3% (vs ~1%)
• Hallucinations: about 3% (vs ~1%)
• Insomnia: about 3% (vs ~2%)

Side effects that can lead to stopping the medication

The most common reason people stopped Ongentys in trials was dyskinesia. If new or worsening dyskinesia happens,
clinicians may adjust the levodopa dose (or other dopaminergic medications) rather than automatically abandoning the plan.

Serious side effects and warnings

Contact a healthcare professional promptly if any of these occur:

• Sudden sleepiness or “sleep attacks”: People taking dopaminergic therapies have reported falling asleep during activities
  like talking, eating, or even driving. Until you know how Ongentys affects you, be careful with activities requiring full alertness.
• Low blood pressure, dizziness, or fainting: Especially when standing up. This can raise fall risk.
• Hallucinations or psychosis-like symptoms: Seeing/hearing things that aren’t there, delusions, agitation, or aggressive behavior.
• Impulse control or compulsive behaviors: Unusual urges to gamble, spend money, binge eat, or increased sexual urges.
• Withdrawal-emergent symptoms when stopping: Fever, confusion, and severe muscle stiffnessseek urgent medical advice.

Drug interactions: what to watch for

Medication interactions matter in Parkinson’s disease because many drugs influence dopamine pathways, blood pressure, alertness, or heart rhythm.
Always share a complete medication list (including OTC meds and supplements) with your prescriber.

Do not use with non-selective MAO inhibitors

Ongentys is contraindicated with non-selective monoamine oxidase (MAO) inhibitors (for example: phenelzine, isocarboxazid, tranylcypromine).
This combination can raise catecholamine levels and increase the risk of excessive blood pressure changes, fast heart rate, or arrhythmias.

Some Parkinson’s medications are selective MAO-B inhibitors (such as rasagiline or selegiline). These are commonly used in PD and may be used
with Ongentys under clinician guidanceyour care team will decide what’s appropriate for your situation.

Caution with certain “catecholamine” drugs

Ongentys may affect drugs metabolized by COMT. Examples include certain medications used in emergency or critical care settings, like
epinephrine, norepinephrine, dopamine, dobutamine, and isoproterenol
(even when given by routes like inhalation). Clinicians may monitor blood pressure and heart rate more closely if these drugs are required.

Alcohol and other sedating medications

If Ongentys contributes to drowsiness, combining it with other sedatives can amplify that effect. A pharmacist can help review your regimen for
“stacked sleepiness.”

Who should not take Ongentys?

Ongentys is not appropriate for everyone. It is contraindicated in people who:

• Take non-selective MAO inhibitors.
• Have pheochromocytoma, paraganglioma, or other catecholamine-secreting tumors.

It may also be avoided or used with extra caution in certain liver or kidney conditions, as discussed above.

Tips for managing common side effects

Side effects don’t automatically mean “this medication failed.” Often, the fix is a targeted adjustmentsometimes to levodopa timing/doseor practical
symptom management. Here are clinician-style conversation starters you can bring to appointments.

If dyskinesia shows up

• Ask whether your levodopa dose should be adjusted now that levodopa may last longer.
• Track when extra movements happen: after levodopa? later in the day? This pattern helps guide dose tweaks.

If constipation becomes the headline

• Hydration, fiber, and movement matter (even a little walking can help).
• Ask about stool softeners or gentle laxatives if lifestyle steps aren’t enough.

If dizziness or faint feelings happen

• Stand up slowly; consider sitting at the edge of the bed for a moment before walking.
• Tell your care teamblood pressure checks (including standing) can be important.

If sleepiness or hallucinations appear

• Report it promptly. These symptoms can be medication-related and may improve with dose adjustments.
• Avoid driving or risky activities until you’re sure you’re alert and stable.

Frequently asked questions

How fast does Ongentys start working?

Some people notice changes within days to a couple of weeks, while for others it takes longer and requires fine-tuning of the overall regimen.
Because it’s affecting levodopa exposure, improvements often show up as less OFF time or smoother transitions rather than a dramatic “wow” moment.

Can Ongentys replace entacapone?

Both are COMT inhibitors used to reduce wearing off. Ongentys is once daily, while entacapone is typically taken with each levodopa dose.
Whether one is better for you depends on symptom patterns, side effects, convenience, and clinician preference.

Can I take Ongentys with my other Parkinson’s meds?

Many people take multiple PD meds together (levodopa plus a dopamine agonist, MAO-B inhibitor, amantadine, etc.).
The key is careful interaction screening and monitoringespecially for low blood pressure, sleepiness, hallucinations, and dyskinesia.

Real-World Experiences: what people commonly notice (about )

People who start Ongentys often describe the experience less like flipping a light switch and more like smoothing out a bumpy road. The goal isn’t
to create “super ON time,” but to reduce the frustrating gaps when levodopa starts to fade early. A common theme is that the day can feel
more predictableand predictability is underrated when Parkinson’s is involved.

One of the first “aha” moments some patients report is realizing how much their routine depends on timing. Ongentys is taken at bedtime and must be
separated from food for a window around the dose. That sounds simple until you remember that humans are snack-oriented creatures. Some people solve
this by setting a “kitchen closed” rule an hour before bed, while others shift their evening snack earlier. A few treat it like a friendly habit tracker:
“If I can remember to charge my phone, I can remember to schedule my capsule.”

The most talked-about tradeoff is dyskinesia. Because Ongentys can boost levodopa’s effect, some people notice extra involuntary movements
after they start itespecially if their levodopa dose was already close to the “too much dopamine” line. This can be alarming at first, but many clinicians
treat it as a signal that the medication is doing what it’s designed to do: increasing levodopa exposure. In practice, the next step is often a careful
levodopa adjustment rather than abandoning Ongentys immediately. Patients and care partners who keep a brief diarywhat time symptoms improved, what time
extra movements appearedoften find those notes make clinic visits more productive.

Another common experience is noticing changes in standing balance or lightheadedness. Some people feel fine sitting or lying down,
but woozy when standing up quickly. Care partners sometimes notice it before the patient does (“You looked pale when you got up”). In real life, “stand up slowly”
is surprisingly powerful advice. People also talk to their clinicians about hydration, compression socks, or medication adjustments if orthostatic symptoms persist.

Constipation comes up a lot, partly because Parkinson’s itself can slow the gut and many PD meds don’t help. When Ongentys adds a nudge in that
direction, people often respond with practical strategies: more water, fiber, prunes (the unofficial fruit of pharmacy), gentle activity, and a plan with their clinician
for occasional medications if needed. The best approach is the boring one: consistent habits.

Finally, patients and caregivers frequently emphasize behavior and sleep monitoring. If someone becomes unusually sleepy during the day, has vivid dreams, develops
hallucinations, or shows impulse-control behaviors (like sudden gambling or compulsive shopping), families often say the key was mentioning it earlywithout shame.
These are known medication-related possibilities, and care teams can adjust therapy. The overall “real world” takeaway: Ongentys tends to work best when it’s part of
a bigger strategytracking OFF time, adjusting levodopa thoughtfully, and treating side effects like solvable problems rather than personal failures.