Entacapone

Antiparkinsonian Drug

Drug class: Dopaminergic Antiparkinsonian Agent belongs to the Catechol-O-methyltransferase Inhibitor, COMT Inhibitor.

Entacapone (COMTAN)（中文：恩他卡朋） is a medication primarily used in the treatment of Parkinson's disease, specifically to manage "wearing-off" sympotms associated with levodopa therapy. Below is detailed information regarding its drug class, strengths, usage, mechanism of action, and other relevant aspects.

Common Strengths of Entacapone

• 200 mg oral tablets are the standard strength available for entacapone

Drug Trade Names

COMTAN

• It is also available in fixed-dose combinations with levodopa and carbidopa under the brand name Stalevo.

Drug Usage

Entacapone is indicated for:

• Treating "wearing-off" symptoms in patients with Parkinson's disease when used in conjunction with levodopa and carbidopa.

Mechanism of Action

Entacapone works by inhibiting the enzyme COMT, which metabolizes levodopa. This inhibition increases the bioavailability of levodopa, allowing it to remain active longer in the body and enhancing its therapeutic effects.

Route of Administration

Orally, and can be taken with or without food.

Dosages

• 200 mg with each dose of levodopa/carbidopa, up to 8 times daily.

Side Effects

Frequency	Adverse reactions
Common Side Effects	Diarrhea
	Dizziness
	Nausea
	Drowsiness
Serious Side Effects	Hallucinations
	Severe diarrhea
	Uncontrolled movements (dyskinesia)
	Sudden sleep episodes during daily activities

Pharmacokinetics

• Onset Time: Peak plasma concentrations occur approximately 1 hour after oral administration.
• Duration: The half-life of entacapone is about 0.3 to 0.7 hours.

Drug Precautions

Pregnancy

• Safety during pregnancy is not established; consult a healthcare provider if or plan to become pregnant.

Breastfeeding

• It is unknown if entacapone passes into breast milkl nursing mothers should consult their doctor before use.

Drug Monitoring Items

Monitoring should include:

• Liver function tests (due to potential liver enzyme elevations)
• Renal function assessments

Drug Interactions

Entacpone has major interactions with the following medications:

• MAO inhibitors (e.g. phenelzine, tranylcypromine): Combining these can potentially lead to severe hypertensive reactions. Entacapone should not be used with non-selective MAO inhibitors.
• Warfarin: Entacapone may increase INR levels in patinets on warfarin therapy. Close monitoring is recommended.

Some moderately significant interactions include:

• Anti depressants (e.g. venlafaxine, desipramine)
• Antidiabetic medications (e.g. hlipizide, rosiglitazone)
• Certain antihypertensives (e.g. irbesartan, losartan)
• Metoclopramide
• Isoproterenol
• Methyldopa

FAQ

How Should I Take the Tablet?

Take entacapone with each dose of levodopa/carbidopa as prescribed. It can be taken with or without food.

What Should I Avoid While Taking?

Avoid alcohol and other sedatives that may increase drowsiness.

What Happens if I Miss a Dose?

Take the missed dose as soon as you remember unless it is close to your next scheduled dose. Do not double up on doses.