Entacapone: What It Does and How to Use It

Entacapone is a COMT inhibitor used with levodopa/carbidopa to help control Parkinson’s symptoms longer. You don’t take it alone — it’s added when levodopa wearing-off becomes a problem. The goal is simple: extend levodopa’s benefit so you get fewer off periods during the day.

How entacapone works and dosing

Entacapone blocks an enzyme (COMT) that breaks down levodopa outside the brain. That means more levodopa reaches your brain and works for longer. Typical dosing is 200 mg of entacapone with each levodopa/carbidopa dose — usually every time you take levodopa. Don’t skip or double doses without checking with your doctor. If you miss a dose, take the next scheduled dose at the usual time; avoid taking two at once.

Many people notice smoother control of movement and fewer fluctuations within a few days, but it can take a couple of weeks to find the best regimen. Your neurologist may adjust your levodopa dose after starting entacapone because increased levodopa effect can cause too much movement (dyskinesia).

Side effects, interactions and practical tips

Common side effects are increased dyskinesia, nausea, diarrhea, and urine that turns a harmless brownish-orange color. If diarrhea is severe or persistent, call your doctor — don’t ignore it. Serious signs that need immediate care include fainting, severe confusion, hallucinations, or signs of liver problems (though entacapone is less likely to hurt the liver than tolcapone).

Watch drug interactions: combining entacapone with MAO inhibitors, certain antidepressants, or other medicines that affect dopamine can change effects or side effects. Tell your pharmacist about all meds and supplements you take. High-protein meals can reduce levodopa absorption, so try spreading protein evenly through the day instead of eating a big protein-heavy meal before a dose.

Store entacapone at room temperature and keep it out of reach of children. If you’re pregnant, breastfeeding, or planning pregnancy, talk to your doctor — data are limited, so decisions are made case by case. For older adults, doctors usually start low and watch closely for confusion or falls.

Practical tips: take entacapone with each levodopa dose for consistent effect; carry a medication list and wear a medical ID if you have advanced Parkinson’s; report new mental changes quickly. If you buy medicine online, use accredited pharmacies and keep prescriptions and records. Small changes in dosing or timing often make a big difference, so work closely with your care team to get steady symptom control.

Questions for your next visit: Is my levodopa dose still right after adding entacapone? What side effects should prompt a call? Are there specific meds I must avoid? These three quick questions help keep treatment safe and useful.