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Entacapone

COMT Inhibitor · Antiparkinsonian

COMT InhibitorAntiparkinsonian
CDSCO approved
EXCRETION
not curated
INTERACTIONS
8 major
SEVERE in our sources
PREGNANCY
Avoid (no information available)
FDA category + note
Top interactionssee all 9
  • DextropropoxypheneSevereDatabaseDDInter
  • IsocarboxazidSevereDatabaseDDInter
  • LinezolidSevereDatabaseDDInter
  • Methylene BlueSevereDatabaseDDInter

Mechanism

Entacapone prevents the peripheral breakdown of levodopa by inhibiting catechol-O-methyltransferase. This action allows more levodopa to reach the brain, thereby increasing its therapeutic effect.

Indications

Adjunct to co-beneldopa or co-careldopa in Parkinson’s disease with ‘end-of-dose’ motor fluctuations (under expert supervision)Parkinson's disease (adjunct to L-DOPA)Adjunctive PD therapy given with each dose of levodopa, for "wearing-off"Used as an adjuvant to levodopa-carbidopa for advanced and fluctuating Parkinson's disease

Dosing

Adult
200 mg by mouth, given with each dose of levodopa with dopa-decarboxylase inhibitor
Hepatic adjustment
Manufacturer advises avoid
Max dose
2 g per day

Pharmacokinetics

Duration
2 h

Contraindications

  • History of neuroleptic malignant syndrome
  • History of non-traumatic rhabdomyolysis
  • Phaeochromocytoma

Side effects

Common
Abdominal painConfusionConstipationDiarrhoeaDizzinessDry mouthFallFatigueHallucinationHyperhidrosisIschaemic heart diseaseMovement disordersNauseaSleep disordersUrine discolourationVomitingorthostatic hypotensionvivid dreamshallucinationsyellow-orange discolouration of urinedyskinesiapostural hypotension
Serious
  • Myocardial infarction
  • Colitis
  • Hepatic disorders
  • Impulse-control disorder
  • Neuroleptic malignant syndrome
  • Rhabdomyolysis
  • Agitation

Pregnancy & lactation

Pregnancy

Avoid (no information available)

Lactation

Avoid (present in milk in animal studies)

Drug interactions

Dextropropoxyphene
Severe
Database

Clinical effect not specified

Source: DDInter

Isocarboxazid
Severe
Database

Clinical effect not specified

Source: DDInter

Linezolid
Severe
Database

Clinical effect not specified

Source: DDInter

Methylene Blue
Severe
Database

Clinical effect not specified

Source: DDInter

Phenelzine
Severe
Database

Clinical effect not specified

Source: DDInter

Procarbazine
Severe
Database

Clinical effect not specified

Source: DDInter

Sodium Oxybate
Severe
Database

Clinical effect not specified

Source: DDInter

Tranylcypromine
Severe
Database

Clinical effect not specified

Source: DDInter

Norepinephrine
Moderate
Database

Effectively increases transmitter supply of norepinephrine.

Source: DDInter

3 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.

Related guidelines

Other COMT Inhibitor drugs

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Continue into a citation-backed clinical answer with the drug context already attached.

Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-10 · House clinical team