Note: This document contains side effect information about entacapone. Some of the dosage forms listed on this page may not apply to the brand name Comtan.
Common side effects of Comtan include: urine discoloration. See below for a comprehensive list of adverse effects.
Applies to entacapone: oral tablet
Along with its needed effects, entacapone (the active ingredient contained in Comtan) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking entacapone:
Some side effects of entacapone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Applies to entacapone: oral tablet
Very common (10% or more): Dyskinesia (up to 27%), hyperkinesia (10%)
Common (1% to 10%): Hypokinesia, dizziness, somnolence, taste perversion, aggravated parkinsonism, dystonia, headache, tremor
Frequency not reported: Falling asleep during activities of daily living
Postmarketing reports: Neuroleptic malignant syndrome
There were no cases of neuroleptic malignant syndrome during clinical trials. Since market introduction, there have been isolated cases, especially following abrupt reduction or discontinuation of this drug and other concomitant dopaminergic drugs.
Very common (10% or more): Nausea (up to 14%), diarrhea (up to 11%)
Common (1% to 10%): Abdominal pain, constipation, vomiting, dry mouth, dyspepsia, flatulence, gastritis, gastrointestinal disorders
Very rare (less than 0.01%): Anorexia
Postmarketing reports: Colitis
In clinical trials, diarrhea occurred in approximately 10% of patients. It was generally mild to moderate, but in 1.3% of people it was severe. Upon discontinuation, diarrhea generally resolved. There have been postmarketing reports of drug-induced microscopic colitis, primarily lymphocytic colitis.
Very common (10% or more): Urine discoloration (10%)
The most commonly reported adverse reactions included dyskinesia, urine discoloration, diarrhea, nausea, hyperkinesia, abdominal pain, vomiting, and dry mouth.
Common (1% to 10%): Dyspnea
Frequency not reported: Pulmonary fibrosis
Common (1% to 10%): Increased sweating
Rare (less than 0.1%): Erythematous, maculopapular rash
Very rare (less than 0.01%): Urticaria
Frequency not reported: Skin hair, beard, and nail discolorations
Common (1% to 10%): Back pain, falls, leg cramps
Postmarketing reports: Rhabdomyolysis
Isolated cases of rhabdomyolysis have occurred in patients treated with this drug. The complicated nature of these cases makes it difficult to determine the role this drug may have had. Rhabdomyolysis has been reported secondary to severe dyskinesias or neuroleptic malignant syndrome (NMS) in patients with Parkinson's disease.
Common (1% to 10%): Anxiety, insomnia, hallucinations, confusion, paranoia
Uncommon (0.1% to 1%): Agitation
Frequency not reported: Impulse control disorders including pathological gambling, increased libido, hypersexuality, compulsive spending or buying, binge eating and compulsive eating
Common (1% to 10%): Purpura, decreased hemoglobin
A clinically significant decrease in hemoglobin has been observed in 1.8% of patients. The underlying mechanism may involve decreased absorption of iron from the gastrointestinal tract.
Common (1% to 10%): Fatigue, asthenia, pain, vertigo
The incidence of myocardial infarction and other ischemic heart disease events was 0.43% and 1.54%, respectively, in an analysis of 13 double-blind studies involving 2082 patients.
Common (1% to 10%): Ischemic heart disease events other than myocardial infarction (e.g., angina pectoris, postural hypotension
Uncommon (0.1% to 1%): Myocardial infarction
Rare (less than 0.1%): Abnormal liver function tests
Postmarketing reports: Hepatitis with mainly cholestatic features
Medically reviewed by BestRx Medical Team Last updated on 1/1/2020.
Source: Drugs.com Comtan