Entacapone

What is Entacapone?

• Entacapone (Comtan), is an inhibitor of catechol-O-methyltransferase (COMT), used in the treatment of Parkinson’s disease as an adjunct to levodopa and carbidopa therapy.

Entacapone

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Entacapone molecule ball

Entacapone

What are the uses of this medicine?

• Entacapone (Comtan), used in combination with levodopa and carbidopa to treat end-of-dose “wearing-off” in patients with Parkinson’s disease.

Limitations of use:

• Entacapone tablet’s effectiveness has not been evaluated in patients with Parkinson’s disease who do not experience end-of-dose “wearing-off”.

How does this medicine work?

• Entacapone is a selective and reversible inhibitor of COMT.
• The mechanism of action of entacapone is believed to be through its ability to inhibit COMT and alter the plasma pharmacokinetics of levodopa.
• When entacapone is given in conjunction with levodopa and an aromatic amino acid decarboxylase inhibitor, such as carbidopa, plasma levels of levodopa are greater and more sustained than after administration of levodopa and an aromatic amino acid decarboxylase inhibitor alone.
• It is believed that at a given frequency of levodopa administration, these more sustained plasma levels of levodopa result in more constant dopaminergic stimulation in the brain, leading to greater effects on the signs and symptoms of Parkinson’s disease.
• The higher levodopa levels also lead to increased levodopa adverse effects, sometimes requiring a decrease in the dose of levodopa.
• In humans, entacapone inhibits the COMT enzyme in peripheral tissues. The effects of entacapone on central COMT activity in humans have not been studied.

Who Should Not Use this medicine ?

This medicine cannot be used in patients who:

• have demonstrated hypersensitivity to the drug or its ingredients.

What drug interactions can this medicine cause?

• Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Be sure to mention any of the following:

• ampicillin, apomorphine (Zydis), bitolterol (Tornalate), chloramphenicol (AK-Chlor, Chloromycetin), cholestyramine (Cholybar, Questran, Questran Light, others), medications that cause drowsiness (including medications for anxiety and sleeping pills), dobutamine (Dobutrex), epinephrine (AsthmaHaler, EpiPen Auto-Injector, Primatene Mist, others), erythromycin (E-Base, E.E.S., E-Mycin, others), isoetharine (Arm-a-Med Isoetharine, Beta-2, Bronkometer, others), isoproterenol (Dispos-a-Med Isoproterenol, Isuprel, Medihaler-Iso, others), methyldopa (Aldomet), phenelzine (Nardil), probenecid (Benemid), rifampin (Rifadin, Rimactane), tranylcypromine (Parnate).

Is this medicine FDA approved?

• Yes, it was FDA approved.

How should this medicine be used?

Recommended dosage:

• The recommended dose of entacapone tablets is one 200 mg tablet administered concomitantly with each levodopa and carbidopa dose to a maximum of 8 times daily (200 mg x 8 = 1,600 mg per day).
• Entacapone tablets should always be administered in association with levodopa and carbidopa. Entacapone has no antiparkinsonian effect of its own.
• Patients With Impaired Hepatic Function: Patients with hepatic impairment should be treated with caution.
• Rapid withdrawal or abrupt reduction in the entacapone tablets dose could lead to emergence of signs and symptoms of Parkinson’s disease.

Administration:

• Entacapone comes as a tablet to take by mouth.
• It is taken with every dose of levodopa and carbidopa, up to 8 times a day.
• Entacapone may be taken with or without food.
• Take entacapone exactly as directed.
• Do not take more or less of it or take it more often than prescribed by your doctor.
• Entacapone helps control the symptoms of Parkinson's disease, but it does not cure it.
• Continue to take entacapone even if you feel well. Do not stop taking entacapone without talking to your doctor.
• Stopping entacapone suddenly may make your Parkinson's disease worse and could have other dangerous effects.
• Your doctor probably will decrease your dose gradually if necessary.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As tablets containing 200 mg entacapone.

This medicine is available in fallowing brand namesː

• Comtan

What side effects can this medication cause?

The most common side effects of this medicine include:

• Sweating increased
• Back pain
• Dyskinesia
• Hyperkinesia
• Hypokinesia
• Dizziness
• Taste perversion
• Anxiety
• Somnolence
• Agitation
• Nausea
• Diarrhea
• Abdominal pain
• Constipation
• Vomiting
• Mouth dry
• Dyspepsia
• Flatulence
• Gastritis
• Gastrointestinal disorders
• Dyspnea
• Purpura
• Urine discoloration
• Fatigue
• Infection bacterial

Less common,but serious side effects may include:

• Hypotension, Orthostatic Hypotension, and Syncope
• Hallucinations and Psychotic-Like Behavior
• Impulse Control and Compulsive Behaviors
• Diarrhea and Colitis
• Dyskinesia
• Renal Toxicity
• Hepatic Impairment

What special precautions should I follow?

• Advise patients that they may develop postural (orthostatic) hypotension with or without symptoms such as dizziness, nausea, syncope, and sweating. Hypotension may occur more frequently during initial therapy. Accordingly, patients should be cautioned against rising rapidly after sitting or lying down, especially if they have been doing so for prolonged periods, and especially at the initiation of treatment with entacapone tablets.
• Dopaminergic therapy in patients with Parkinson’s disease has been associated with hallucinations. Patients with a major psychotic disorder should ordinarily not be treated with entacapone tablets because of the risk of exacerbating psychosis. In addition, certain medications used to treat psychosis may exacerbate the symptoms of Parkinson's disease and may decrease the effectiveness of entacapone tablets.
• Postmarketing reports suggest that patients treated with anti-Parkinson medications can experience intense urges to gamble, increased sexual urges, intense urges to spend money uncontrollably, and other intense urges. Physicians should consider dose reduction or stopping entacapone tablets if a patient develops such urges while taking entacapone tablets.
• Inform patients that diarrhea may occur with entacapone tablets and it may have a delayed onset. Sometimes prolonged diarrhea may be caused by colitis (inflammation of the large intestine). Patients with diarrhea should drink fluids to maintain adequate hydration and monitor for weight loss. If diarrhea associated with entacapone tablets is prolonged, discontinuing the drug is expected to lead to resolution, if diarrhea continues after stopping entacapone, further diagnostic investigations may be needed.
• Entacapone tablets may potentiate the dopaminergic side effects of levodopa and may cause or exacerbate preexisting dyskinesia.
• Cases of severe rhabdomyolysis have been reported following the approval of entacapone tablets. Signs and symptoms include fever, alteration of consciousness, myalgia, increased values of creatine phosphokinase (CPK) and myoglobin.
• Cases of a symptom complex resembling neuroleptic malignant syndrome (NMS) characterized by elevated temperature, muscular rigidity, altered consciousness, and elevated CPK have been reported in association with the rapid dose reduction or withdrawal of other dopaminergic drugs. Prescribers should exercise caution when discontinuing entacapone treatment. When considered necessary, withdrawal should proceed slowly.
• Cases of retroperitoneal fibrosis, pulmonary infiltrates, pleural effusion, and pleural thickening have been reported in some patients treated with ergot derived dopaminergic agents.
• Patients with hepatic impairment should be treated with caution.
• Advise patients that they should neither drive a car nor operate other complex machinery until they have gained sufficient experience on entacapone tablets to gauge whether or not it affects their mental and/or motor performance adversely. Warn patients about the possibility of sudden onset of sleep during daily activities, in some cases without awareness or warning signs, when they are taking dopaminergic agents, including entacapone tablets.
• Because of the possible additive sedative effects, caution should be used when patients are taking other CNS depressants in combination with entacapone tablets.
• Inform patients that nausea may occur, especially at the initiation of treatment with entacapone tablets.
• Tell patients that treatment with entacapone may cause a change in the color of their urine (a brownish orange discoloration) that is not clinically relevant.
• Entacapone is excreted into maternal milk in rats. Because of the possibility that entacapone may be excreted into human maternal milk, advise patients to notify their physicians if they intend to breastfeed or are breastfeeding an infant.

What to do in case of emergency/overdose?

Symptoms of overdose may include:

• somnolence and decreased activity, states related to depressed level of consciousness (e.g., coma, confusion and disorientation) and discolorations of skin, tongue, and urine, as well as restlessness, agitation, and aggression.

Management of overdosage:

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.
• Management of entacapone tablets overdose is symptomatic; there is no known antidote to entacapone tablets.
• Hospitalization is advised, and general supportive care is indicated.
• There is no experience with hemodialysis or hemoperfusion, but these procedures are unlikely to be of benefit, because entacapone is highly bound to plasma proteins.
• An immediate gastric lavage and repeated doses of charcoal over time may hasten the elimination of entacapone tablets by decreasing its absorption and reabsorption from the gastrointestinal (GI) tract.
• The adequacy of the respiratory and circulatory systems should be carefully monitored and appropriate supportive measures employed.
• The possibility of drug interactions, especially with catechol-structured drugs, should be borne in mind.

Can this medicine be used in pregnancy?

• Pregnancy Category C.
• There is no experience from clinical studies regarding the use of entacapone tablets in pregnant women.
• Therefore, entacapone tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Can this medicine be used in children?

• Safety and effectiveness in pediatric patients have not been established.

What are the active and inactive ingredients in this medicine?

• Entacapone is available as tablets containing 200 mg entacapone.
• The inactive ingredients of the entacapone tablet are microcrystalline cellulose, sodium starch glycolate, hypromelloses, polyoxyl 40 hydrogenated castor oil, purified water, magnesium stearate, polyethylene glycols, ferric oxide red, ferric oxide yellow, titanium dioxide, polyvinyl alcohol and talc.

Who manufactures and distributes this medicine?

Entacapone tablets are Marketed by:

• Ajanta Pharma USA Inc.
• Bridgewater, NJ
• Made in India.

What should I know about storage and disposal of this medication?

• Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

• Dailymed label info on Entacapone
• FDA Entacapone

Entacapone Resources
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