Carbidopa, Levodopa, and Entacapone

Dosage and Administration ( 2.1 ) 03/2026 Warnings and Precautions ( 5.10 ) 03/2026

1 INDICATIONS AND USAGE Carbidopa, levodopa and entacapone tablets are indicated for the treatment of Parkinson's disease. Carbidopa, levodopa and entacapone tablets can be used: • To substitute (with equivalent strengths of each of the three components) carbidopa/levodopa and entacapone previously administered as individual products. • To replace carbidopa/levodopa therapy (without entacapone) when patients experience the signs and symptoms of end-of-dose “wearing-off” and when they have been taking a total daily dose of levodopa of 600 mg or less and have not been experiencing dyskinesias. Carbidopa, levodopa and entacapone tablets, a combination drug consisting of levodopa (aromatic amino acid), carbidopa (aromatic amino acid decarboxylation inhibitor), and entacapone (catechol-O-methyltransferase (COMT) inhibitor) is indicated for the treatment of Parkinson's disease. Carbidopa, levodopa and entacapone tablets is to be used: • To substitute (with equivalent strengths of each of the three components) for carbidopa/levodopa and entacapone previously administered as individual products ( 1 ) • To replace carbidopa/levodopa therapy (without entacapone) when patients experience the signs and symptoms of end-of-dose “wearing-off” and when they have been taking a total daily dose of levodopa of 600 mg or less and have not been experiencing dyskinesias ( 1 )

2 DOSAGE AND ADMINISTRATION Carbidopa, levodopa and entacapone tablets should be used as a substitute for patients already stabilized on equivalent doses of carbidopa/levodopa and entacapone. However, some patients who have been stabilized on a given dose of carbidopa/levodopa may be treated with carbidopa, levodopa and entacapone tablets if a decision has been made to add entacapone (see below). Therapy should be individualized and adjusted according to the desired therapeutic response. • Evaluate vitamin B6 levels prior to starting treatment with carbidopa/levodopa therapies. ( 2.1 ) • The optimum daily dosage of carbidopa, levodopa and entacapone tablets must be determined by careful titration in each patient ( 2.2 ) • Individual tablets should not be split or fractionated. Administer only one tablet at each dosing interval ( 2.6 ) 2.1 Management of Vitamin B6 Levels Evaluate vitamin B6 levels prior to initiating carbidopa/levodopa therapies, including carbidopa, levodopa and entacapone tablets, periodically during treatment, and as clinically indicated [see Warnings and Precautions ( 5.10 )] . If vitamin B6 levels are low, supplement to sufficient levels per standard of care. Patients may initiate and continue treatment with carbidopa, levodopa and entacapone tablets while supplementing vitamin B6. 2.2 Dosing Information The optimum daily dosage of carbidopa, levodopa and entacapone tablets must be determined by careful titration in each patient. Clinical experience with daily doses above 1,600 mg of entacapone is limited. The maximum recommended daily dose of carbidopa, levodopa and entacapone tablets depends on the strength used. The maximum number of tablets to be used in a 24-hour period is less with the highest strength of carbidopa, levodopa and entacapone tablets than with lower strengths (see Table 1 ). Studies show that peripheral dopa decarboxylase is saturated by carbidopa at approximately 70 mg per day to 100 mg per day. Patients receiving less than this amount of carbidopa are more likely to experience nausea and vomiting. Table 1: Maximum Recommended Dose of Carbidopa, Levodopa and Entacapone Tablets in a 24-hour Period Carbidopa, Levodopa and Entacapone Tablets Dosage Strength Maximum Number of Tablets in a 24-hour Period 12.5 mg per 50 mg per 200 mg 8 18.75 mg per 75 mg per 200 mg 25 mg per 100 mg per 200 mg 31.25 mg per 125 mg per 200 mg 37.5 mg per 150 mg per 200 mg 50 mg per 200 mg per 200 mg 6 2.3 Converting Patients from Carbidopa, Levodopa, and Entacapone to Carbidopa, Levodopa and Entacapone tablets Patients currently treated with entacapone 200 mg with each dose of non-extended release carbidopa/levodopa tablet, can switch to the corresponding strength of carbidopa, levodopa and entacapone tablets containing the same amounts of levodopa and carbidopa. For example, patients receiving one tablet of carbidopa/levodopa 25 mg/100 mg and one tablet of entacapone 200 mg at each administration can switch to a single carbidopa, levodopa and entacapone tablet containing 25 mg of carbidopa, 100 mg of levodopa and 200 mg of entacapone. 2.4 Converting Patients from Carbidopa and Levodopa Products to Carbidopa, Levodopa and Entacapone tablets There is no experience in transferring patients currently treated with extended release formulations of carbidopa/levodopa, or carbidopa/levodopa products that are not combined in a 1:4 ratio of carbidopa to levodopa. Patients with a history of moderate or severe dyskinesias or taking more than 600 mg of the levodopa component per day are likely to require a reduction in their daily levodopa dose when entacapone is added. Because dose adjustment of the individual carbidopa or levodopa component is not possible with fixed-dose products, initially titrate patients to a dose that is tolerated and that meets their individual therapeutic need using a separate carbidopa/levodopa tablet (1:4 ratio) plus an entacapone tablet. Once the patient's individual dose of carbidopa/levodopa …

3 DOSAGE FORMS AND STRENGTHS Each carbidopa, levodopa and entacapone tablet, provided in 6 single-dose strengths, contains carbidopa and levodopa in a 1:4 ratio and a 200 mg dose of entacapone. Carbidopa, levodopa and entacapone tablets are supplied as film-coated tablets for oral administration in the following 6 strengths: Carbidopa, levodopa and entacapone film-coated tablets containing 12.5 mg of carbidopa, 50 mg of levodopa and 200 mg of entacapone. The round, bi-convex shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 50” on one side. Carbidopa, levodopa and entacapone film-coated tablets containing 18.75 mg of carbidopa, 75 mg of levodopa and 200 mg of entacapone. The oval-shaped tablets are light brownish red, unscored and embossed with code “LCE 75” on one side. Carbidopa, levodopa and entacapone film-coated tablets containing 25 mg of carbidopa, 100 mg of levodopa and 200 mg of entacapone. The oval-shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 100” on one side. Carbidopa, levodopa and entacapone film-coated tablets containing 31.25 mg of carbidopa, 125 mg of levodopa and 200 mg of entacapone. The oval-shaped tablets are light brownish red, unscored and embossed with code “LCE 125” on one side. Carbidopa, levodopa and entacapone film-coated tablets containing 37.5 mg of carbidopa, 150 mg of levodopa and 200 mg of entacapone. The elongated-ellipse shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 150” on one side. Carbidopa, levodopa and entacapone film-coated tablets containing 50 mg of carbidopa, 200 mg of levodopa and 200 mg of entacapone. The oval shaped tablets are dark brownish red, unscored, and embossed “LCE 200” on one side. Each carbidopa, levodopa and entacapone tablet contains a 1:4 ratio of carbidopa to levodopa and 200 mg of entacapone (mg of carbidopa per mg of levodopa per mg of entacapone) • Carbidopa, levodopa and entacapone tablets (12.5 mg per 50 mg per 200 mg) • Carbidopa, levodopa and entacapone tablets (18.75 mg per 75 mg per 200 mg) • Carbidopa, levodopa and entacapone tablets (25 mg per 100 mg per 200 mg) • Carbidopa, levodopa and entacapone tablets (31.25 mg per 125 mg per 200 mg) • Carbidopa, levodopa and entacapone tablets (37.5 mg per 150 mg per 200 mg) • Carbidopa, levodopa and entacapone tablets (50 mg per 200 mg per 200 mg)

4 CONTRAINDICATIONS Carbidopa, levodopa and entacapone tablets are contraindicated in patients: • Taking nonselective monoamine oxidase (MAO) inhibitors (e.g., phenelzine and tranylcypromine). These nonselective MAO inhibitors must be discontinued at least two weeks prior to initiating therapy with carbidopa, levodopa and entacapone tablets. • With narrow-angle glaucoma. • Concomitant use of nonselective monoamine oxidase (MAO) inhibitors ( 4 ) • Narrow-angle glaucoma ( 4 )

6 ADVERSE REACTIONS The following adverse reactions are discussed in more detail in the Warnings and Precautions sections of labeling: • Falling Asleep During Activities of Daily Living and Somnolence [see Warnings and Precautions (5.1) ] • Hypotension/Orthostatic Hypotension and Syncope [see Warnings and Precautions (5.2) ] • Dyskinesia [see Warnings and Precautions (5.3) ] • Depression and suicidality [see Warnings and Precautions (5.4) ] • Hallucinations/Psychotic-Like Behavior [see Warnings and Precautions (5.5) ] • Impulse Control and/or Compulsive Behaviors [see Warnings and Precautions (5.6) ] • Withdrawal-Emergent Hyperpyrexia and Confusion [see Warnings and Precautions (5.7) ] • Diarrhea and Colitis [see Warnings and Precautions (5.8) ] • Rhabdomyolysis [see Warnings and Precautions (5.9) ] • Vitamin B6 Deficiency and Seizures [see Warnings and Precautions (5.10) ] • Peptic Ulcer Disease [see Warnings and Precautions (5.13) ] The most common adverse reactions (incidence 3% higher than placebo incidence) are dyskinesias, hyperkinesia, diarrhea, nausea, abdominal pain, vomiting, dry mouth and urine discoloration ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Sandoz Inc. at 1-800-525-8747 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the incidence of adverse reactions (number of unique patients experiencing an adverse reaction associated with treatment/total number of patients treated) observed in the clinical trials of a drug cannot be directly compared to the incidence of adverse reactions in the clinical trials of another drug and may not reflect the incidence of adverse reactions observed in clinical practice. Entacapone The most commonly observed adverse reactions (incidence at least 3% greater than placebo incidence) in the double-blind, carbidopa-levodopa-placebo-controlled trials of entacapone (N=1,003 patients) associated with the use of carbidopa-levodopa-entacapone alone and not seen at an equivalent frequency among the placebo-treated patients were: dyskinesia, diarrhea, nausea, hyperkinesia, abdominal pain, vomiting, dry mouth, and urine discoloration. The treatment difference incidence for premature study discontinuation for entacapone with levodopa and dopa decarboxylase inhibitor in the double-blind, placebo-controlled trials was 5%. The treatment difference incidence for the most frequent causes of study discontinuation was 2% for diarrhea, and 1% for other specific adverse reactions including psychiatric reasons, dyskinesia/ hyperkinesia, nausea, or abdominal pain. Adverse Reaction Incidence in Controlled Clinical Studies of Entacapone Table 2 lists treatment emergent adverse reactions that occurred in at least 1% of patients treated with carbidopa/levodopa and 200 mg of entacapone who participated in the double-blind, placebo-controlled studies, and that were numerically more common in this group than in the carbidopa/levodopa plus placebo group. In these studies, either entacapone or placebo was added to carbidopa/levodopa (or benserazide/levodopa). Table 2: Summary of Patients With Adverse Reactions After Start of Trial Drug Administration At Least 1% in Entacapone Group and Greater Than Placebo SYSTEM ORGAN CLASS Carbidopa/levodopa plus Entacapone Carbidopa/levodopa plus Placebo Adverse Reaction (n=603) % of patients (n=400) % of patients SKIN AND APPENDAGES DISORDERS Sweating Increased 2 1 MUSCULOSKELETAL SYSTEM DISORDERS Back Pain 5 3 CENTRAL AND PERIPHERAL NERVOUS SYSTEM DISORDERS Dyskinesia 25 15 Hyperkinesia 10 5 Hypokinesia 9 8 Dizziness 8 6 SPECIAL SENSES, OTHER DISORDERS Taste Perversion 1 0 PSYCHIATRIC DISORDERS Anxiety 2 1 Somnolence 2 0 Agitation 1 0 GASTROINTESTINAL SYSTEM DISORDERS Nausea 14 8 Diarrhea 10 4 Abdominal Pain 8 4 Constipation 6 4 Vomiting 4 1 Mouth Dry 3 0 Dyspepsia 2 1 Flatulence 2 0 Gastritis 1 0 Gastrointestinal Disorders NOS 1 0 RESPIRATORY SYSTEM DISORDERS …

7 DRUG INTERACTIONS • Drugs metabolized by COMT: use with caution ( 5.11 , 7.2 ) • Anti-hypertensive agents: dose adjustment may be required ( 7.3 ) • Tricyclic antidepressants: risk of hypertension and dyskinesia reported during concomitant use with carbidopa/levodopa ( 7.4 ) • Dopamine D2 receptor antagonists, isoniazid, phenytoin, papaverine and iron salts: may reduce efficacy of carbidopa, levodopa and entacapone tablets ( 7.5 , 7.6 , 7.7 , 7.8 , 7.9 ) • Drugs that interfere with biliary excretion, glucuronidation and intestinal beta-glucuronidase: dose adjustment of carbidopa, levodopa and entacapone tablets may be required ( 7.10 ) • Drugs metabolized by CYP2C9 (e.g., coumadin): dose adjustment of carbidopa, levodopa and entacapone tablets may be required; monitor INR when initiating carbidopa, levodopa and entacapone tablets in patients on coumadin ( 7.11 ) 7.1 MAO Inhibitors Patients receiving nonselective MAO inhibitors and carbidopa, levodopa and entacapone may be at risk of increased adrenergic tone. Therefore, the use of carbidopa, levodopa and entacapone tablets is contraindicated in patients receiving nonselective MAO inhibitors [see Contraindications (4) ]. 7.2 Drugs Metabolized by Catechol-O-Methyltransferase (COMT) Drugs known to be metabolized by COMT, such as isoproterenol, epinephrine, norepinephrine, dopamine, dobutamine, alpha-methyldopa, apomorphine, isoetherine, and bitolterol should be administered with caution in patients receiving entacapone regardless of the route of administration (including inhalation), as their interaction may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure [see Warnings and Precautions (5.11) ]. 7.3 Antihypertensive Agents Symptomatic postural hypotension has occurred when carbidopa/levodopa was added to the treatment of patients receiving antihypertensive drugs. When starting therapy with carbidopa, levodopa and entacapone tablets, dosage adjustment of antihypertensive drug may be required. 7.4 Tricyclic Antidepressants There have been reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use of tricyclic antidepressants and carbidopa/levodopa. 7.5 Dopamine D2 Receptor Antagonists Dopamine D2 receptor antagonists (e.g., metoclopramide, phenothiazines, butyrophenones, risperidone) may reduce the therapeutic effects of levodopa. 7.6 Isoniazid Isoniazid may reduce the therapeutic effects of levodopa, a dose increase may be necessary. 7.7 Phenytoin The beneficial effects of levodopa in Parkinson's disease have been reported to be reversed by phenytoin. Patients taking phenytoin with carbidopa/levodopa should be carefully observed for loss of therapeutic response. Carbidopa, levodopa and entacapone tablets dosage should be increased as clinically needed in patients receiving phenytoin. 7.8 Papaverine The beneficial effects of levodopa in Parkinson's disease have been reported to be reversed by papaverine. Patients taking papaverine with carbidopa/levodopa should be carefully observed for loss of therapeutic response. Carbidopa, levodopa and entacapone tablets dosage should be increased as clinically needed in patients receiving papaverine. 7.9 Iron Salts Iron salts or multi vitamins containing iron salts should be coadministered with caution. Iron salts can form chelates with levodopa, carbidopa and entacapone and consequently reduce bioavailability of levodopa, carbidopa and entacapone. 7.10 Drugs Known to Interfere with Biliary Excretion, Glucuronidation, and Intestinal Beta-glucuronidase As most entacapone excretion is via the bile, caution should be exercised when drugs known to interfere with biliary excretion, glucuronidation, and intestinal beta-glucuronidase are given concurrently with entacapone. These include probenecid, cholestyramine, and some antibiotics (e.g., erythromycin, rifampicin, ampicillin and chloramphenicol). 7.11 Drugs Metabolized via CYP2C9 (e.g., coumadin) The dosag …

8 USE IN SPECIFIC POPULATIONS • Pregnancy: based on animal data, may cause fetal harm ( 8.1 ) 8.1 Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of carbidopa, levodopa and entacapone tablets in pregnant women. In animals, administration of carbidopa-levodopa or entacapone during pregnancy was associated with developmental toxicity, including increased incidences of fetal malformations ( see Data ). The estimated background risk of major birth defects and miscarriage in the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2 to 4% and 15 to 20%, respectively. Data Animal data In nonclinical studies in which carbidopa-levodopa was administered to pregnant animals, increased incidences of visceral and skeletal malformations were observed in rabbits at all doses and ratios of carbidopa-levodopa tested, which ranged from 10 times (carbidopa)-5 times (levodopa) to 20 times (carbidopa)-10 times (levodopa) the maximum recommended human dose (MRHD) of 1,600 mg/day. In rats, there was a decrease in the number of live pups delivered by dams receiving approximately two times (carbidopa)-five times (levodopa) the MRHD throughout organogenesis. No effects on malformation frequencies were observed in mice receiving up to 20 times the MRHD of carbidopa-levodopa. In embryo-fetal development studies of entacapone, pregnant animals received doses of up to 1,000 mg/kg/day (rats) or 300 mg/kg/day (rabbits) throughout organogenesis. Increased incidences of fetal variations were evident in litters from rats treated with the highest dose, in the absence of overt signs of maternal toxicity. The maternal plasma entacapone exposure (AUC) associated with this dose was approximately 34 times that in humans at the MRHD. Increased frequencies of abortions and late/total resorptions and decreased fetal weights were observed in the litters of rabbits treated with maternally toxic doses of 100 mg/kg/day (plasma AUCs less than that in humans at the MRHD) or greater. There were no increases in malformation rates in these studies. When entacapone was administered to female rats prior to mating and during early gestation, an increased incidence of fetal eye anomalies (macrophthalmia, microphthalmia, anophthalmia) was observed in the litters of dams treated with doses of 160 mg/kg/day (plasma AUCs seven times that in humans at the MRHD) or greater, in the absence of maternal toxicity. Administration of up to 700 mg/kg/day (plasma AUCs 28 times that in humans at the MRHD) to rats during the latter part of gestation and throughout lactation produced no evidence of developmental impairment in the offspring. 8.2 Lactation Risk Summary Levodopa has been detected in human milk after administration of carbidopa-levodopa. There are no data on the presence of entacapone or carbidopa in human milk, the effects of levodopa, carbidopa, or entacapone on the breastfed infant, or the effects on milk production. However, inhibition of lactation may occur because levodopa decreases secretion of prolactin [see Clinical Pharmacology ( 12.6 )]. Carbidopa and entacapone are excreted in rat milk. In lactating rat, oral administration of radiolabeled entacapone resulted in levels of entacapone and/or metabolites in milk up to 2 to 3 times that in plasma. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for carbidopa, levodopa and entacapone tablets and any potential adverse effects on the breastfed infant from carbidopa, levodopa and entacapone tablets or from the underlying maternal condition. 8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established. 8.5 Geriatric Use Of the total number of subjects in clinical studies of carbidopa, levodopa and entacapone tablets, 43.8% were 65 years old and over, while 7.2% were …

12.1 Mechanism of Action Levodopa Current evidence indicates that symptoms of Parkinson's disease are related to depletion of dopamine in the corpus striatum. Administration of dopamine is ineffective in the treatment of Parkinson's disease because it does not cross the blood-brain barrier. However, levodopa the metabolic precursor of dopamine, does cross the blood-brain barrier, and is presumably converted to dopamine in the brain. This is thought to be the mechanism whereby levodopa relieves the symptoms of Parkinson's disease. Carbidopa When levodopa is administered orally, it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. Carbidopa inhibits the decarboxylation of peripheral levodopa, making more levodopa available for delivery to the brain. Entacapone Entacapone is a selective and reversible inhibitor of catechol-O-methyltransferase (COMT). COMT catalyzes the transfer of the methyl group of S-adenosyl-L-methionine to the phenolic group of substrates that contain a catechol structure. Physiological substrates of COMT include DOPA, catecholamines (dopamine, norepinephrine, and epinephrine) and their hydroxylated metabolites. When decarboxylation of levodopa is prevented by carbidopa, COMT becomes the major metabolizing enzyme for levodopa, catalyzing its metabolism to 3‐methoxy‐4‐hydroxy‐L‐phenylalanine (3‐OMD).

11 DESCRIPTION Carbidopa, levodopa and entacapone tablets is a combination of carbidopa, levodopa, and entacapone for the treatment of Parkinson's disease. Carbidopa, an inhibitor of aromatic amino acid decarboxylation, is a white, crystalline compound, slightly soluble in water, with a molecular weight of 244.3. It is designated chemically as (-)-L-(α-hydrazino-(α-methyl-β-(3,4-dihydroxybenzene) propanoic acid monohydrate. Its empirical formula is C 10 H 14 N 2 O 4 •H 2 O, and its structural formula is: Tablet content is expressed in terms of anhydrous carbidopa, which has a molecular weight of 226.3. Levodopa, an aromatic amino acid, is a white, crystalline compound, slightly soluble in water, with a molecular weight of 197.2. It is designated chemically as (-)-L-α-amino-β-(3,4-dihydroxybenzene) propanoic acid. Its empirical formula is C 9 H 11 NO 4 , and its structural formula is: Entacapone, a COMT inhibitor, is a nitro-catechol-structured compound with a molecular weight of 305.3. The chemical name of entacapone is (E)-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)-N,N-diethyl-2-propenamide. Its empirical formula is C 14 H 15 N 3 O 5 and its structural formula is: Carbidopa, levodopa and entacapone tablets are supplied as tablets in 6 strengths: Carbidopa, levodopa and entacapone tablets: 12.5 mg of carbidopa, 50 mg of levodopa and 200 mg of entacapone Carbidopa, levodopa and entacapone tablets: 18.75 mg of carbidopa, 75 mg of levodopa and 200 mg of entacapone Carbidopa, levodopa and entacapone tablets: 25 mg of carbidopa, 100 mg of levodopa and 200 mg of entacapone Carbidopa, levodopa and entacapone tablets: 31.25 mg of carbidopa, 125 mg of levodopa and 200 mg of entacapone Carbidopa, levodopa and entacapone tablets: 37.5 mg of carbidopa, 150 mg of levodopa and 200 mg of entacapone Carbidopa, levodopa and entacapone tablets: 50 mg of carbidopa, 200 mg of levodopa and 200 mg of entacapone Inactive Ingredients: corn starch, croscarmellose sodium, glycerol 85%, hypromellose, magnesium stearate, mannitol, polysorbate 80, povidone, sucrose, red iron oxide, and titanium dioxide. Tablets containing 12.5 mg of carbidopa, 50 mg of levodopa and 200 mg of entacapone, tablets containing 25 mg of carbidopa, 100 mg of levodopa and 200 mg of entacapone, and tablets containing 37.5 mg of carbidopa, 150 mg of levodopa and 200 mg of entacapone also contain yellow iron oxide. carbidopa_chemstructure levodopa_chemstructure entacapone_chemstructure

10 OVERDOSAGE 10.1 Signs and Symptoms of Overdosage There are very few cases of overdose with levodopa reported in the published literature. Based on the available information, the acute symptoms of levodopa and dopa decarboxylase inhibitor overdose can be expected to arise from dopaminergic overstimulation. Doses of a few grams may result in CNS disturbances, with an increasing likelihood of cardiovascular disturbance (e.g., hypotension, tachycardia) and more severe psychiatric problems at higher doses. An isolated report of rhabdomyolysis and another of transient renal insufficiency suggest that levodopa overdose may give rise to systemic complications, secondary to dopaminergic overstimulation. COMT inhibition by entacapone treatment is dose-dependent. A massive overdose of entacapone may theoretically produce a 100% inhibition of the COMT enzyme in people, thereby preventing the O-methylation of endogenous and exogenous catechols. In clinical trials, the highest single dose of entacapone administered to humans was 800 mg, resulting in a plasma concentration of 14.1 mcg per mL. The highest daily dose given to humans was 2,400 mg, administered in one study as 400 mg six times daily with carbidopa/levodopa for 14 days in 15 Parkinson's disease patients, and in another study as 800 mg three times daily for 7 days in 8 healthy volunteers. At this daily dose, the peak plasma concentrations of entacapone averaged 2.0 mcg per mL (at 45 min, compared to 1.0 mcg per mL and 1.2 mcg per mL with 200 mg entacapone at 45 min.). Abdominal pain and loose stools were the most commonly observed adverse events during this study. Daily doses as high as 2,000 mg entacapone have been administered as 200 mg 10 times daily with carbidopa/levodopa or benserazide/levodopa for at least 1 year in 10 patients, for at least 2 years in 8 patients and for at least 3 years in 7 patients. Overall, however, clinical experience with daily doses above 1,600 mg is limited. 10.2 Management of Overdosage Hospitalization is advised, and general supportive measures should be employed, along with immediate gastric lavage and repeated doses of charcoal over time. This may hasten the elimination of entacapone in particular, by decreasing its absorption and reabsorption from the GI tract. Intravenous fluids should be administered judiciously and an adequate airway maintained. Respiratory, circulatory and renal function should be monitored and appropriate supportive measures employed. Electrocardiographic monitoring should be instituted and the patient carefully observed for the development of arrhythmias; if required, appropriate antiarrhythmic therapy should be given. The possibility that the patient may have taken other drugs, increasing the risk of drug interactions (especially catechol-structured drugs) should be taken into consideration. To date, no experience has been reported with dialysis; hence, its value in overdosage is not known. Hemodialysis or hemoperfusion is unlikely to reduce entacapone levels due to its high binding to plasma proteins. Pyridoxine is not effective in reversing the actions of carbidopa, levodopa and entacapone tablets.

16 HOW SUPPLIED/STORAGE AND HANDLING Carbidopa, levodopa and entacapone tablets are supplied as film-coated tablets for oral administration in the following six strengths: Carbidopa, levodopa and entacapone film-coated tablets containing 12.5 mg of carbidopa, 50 mg of levodopa, and 200 mg of entacapone. The round, bi-convex shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 50” on one side. NDC 0781-5613-01 HDPE bottle of 100 tablets Carbidopa, levodopa and entacapone film-coated tablets containing 18.75 mg of carbidopa, 75 mg of levodopa, and 200 mg of entacapone. The oval-shaped tablets are light brownish red, unscored and embossed with code “LCE 75” on one side. NDC 0781-5625-01 HDPE bottle of 100 tablets Carbidopa, levodopa and entacapone film-coated tablets containing 25 mg of carbidopa, 100 mg of levodopa, and 200 mg of entacapone. The oval-shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 100” on one side. NDC 0781-5637-01 HDPE bottle of 100 tablets Carbidopa, levodopa and entacapone film-coated tablets containing 31.25 mg of carbidopa, 125 mg of levodopa, and 200 mg of entacapone. The oval-shaped tablets are light brownish red, unscored and embossed with code “LCE 125” on one side. NDC 0781-5641-01 HDPE bottle of 100 tablets Carbidopa, levodopa and entacapone film-coated tablets containing 37.5 mg of carbidopa, 150 mg of levodopa, and 200 mg of entacapone. The elongated-ellipse shaped tablets are brownish- or greyish-red, unscored, and embossed “LCE 150” on one side. NDC 0781-5654-01 HDPE bottle of 100 tablets Carbidopa, levodopa and entacapone film-coated tablets containing 50 mg of carbidopa, 200 mg of levodopa, and 200 mg of entacapone. The oval shaped tablets are dark brownish red, unscored, and embossed “LCE 200” on one side. NDC 0781-5669-01 HDPE bottle of 100 tablets Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Dispense contents in a tight, light-resistant container as defined in the USP with a child-resistant closure.