Daily Dosage Guidelines for Entacapone/Codan

Entacapone is a selective and reversible COMT inhibitor. Its core mechanism of action is to inhibit the peripheral metabolism of levodopa by COMT into 3-methoxydopa, thereby increasing the concentration of levodopa entering the central nervous system and prolonging its efficacy. Therefore, entacapone is usually not used alone, but in combination with levodopa/carbidopa or levodopa/benserazide to improve fluctuations in motor symptoms in patients with Parkinson's disease.

This product is an oral preparation. Each tablet contains 200 mg of entacapone. It should be taken at the same time as levodopa/carbidopa or levodopa/benserazide, 1 tablet each time. The maximum recommended dose is 200 mg each time, up to 10 times a day, that is, the total daily dose is 2000 mg. It is not recommended to exceed this range. Exceeding the dose may increase the risk of adverse reactions, such as hypotension, diarrhea, drowsiness, or worsening of movement disorders. For patients who have just started taking combined medication, the original levodopa regimen can be maintained first, followed by observation for 1 to 2 weeks after adding entacapone, and the levodopa dose can be gradually fine-tuned based on the motor control effect.

In terms of administration method, entacapone can be taken with or after meals to reduce gastrointestinal discomfort; however, the time intervals must be kept even to avoid prolonged "off period" or symptom fluctuations due to missed doses. Some patients have a slow "onset" after getting up in the morning. Entacapone can be used simultaneously with the first dose of levodopa to shorten the start-up time and improve morning stiffness.

For elderly patients or those with mildly impaired liver function, there is generally no need to adjust the dose, but clinical monitoring should be strengthened; in the case of obvious liver dysfunction, use should be avoided. Renal insufficiency generally has a minor effect on the metabolism of entacapone, but caution is warranted. Drug metabolism is mainly carried out through the liver pathway, and the half-life is short, so regular administration is the key to ensuring efficacy.

Reference materials:https://www.drugs.com/mtm/comtan.html