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Carbidopa / Levodopa Dosage

Medically reviewed by Last updated on Jun 7, 2021.

Applies to the following strengths: 10 mg-100 mg; 25 mg-100 mg; 25 mg-250 mg; 50 mg-200 mg; 4.63 mg-20 mg/mL; 23.75 mg-95 mg; 36.25 mg-145 mg; 48.75 mg-195 mg; 61.25 mg-245 mg

Usual Adult Dose for Parkinson's Disease

Optimum dosage is determined by careful individual titration: All doses expressed as CARBIDOPA-LEVODOPA

Immediate-release including Oral disintegrating tablets:
Initial dose: 25 mg-100 mg orally three times a day or 10 mg-100 mg orally 3 or 4 times a day

  • Increase by 1 tablet every day or every other day as needed until a dose of 8 tablets is reached; may use a combination of tablets from both ratios (1:4 or 1:10) to provide the optimum dose.
Conversion from LEVODOPA:
  • Levodopa should be discontinued at least 12 hours before starting carbidopa-levodopa; initiate with approximately 25% of the previous levodopa dose.
  • Suggested dose for patients receiving less than levodopa 1500 mg per day: 25 mg-100 mg orally 3 or 4 times a day.
  • Suggested dose for patients receiving more than levodopa 1500 mg per day: 25 mg-250 mg orally 3 or 4 times a day.

Sustained-Release Tablets (SINEMET CR):
  • Initial dose (levodopa-naive): 50 mg-200 mg orally twice a day; initial dosage should be given at intervals of more than 6 hours
  • Dose and dosing interval may be increased or decreased at intervals of at least 3 days based on therapeutic response
  • Dose range: Most patients will require levodopa 400 to 1600 mg/day in divided doses every 4 to 8 hours during waking hours; doses of 2400 mg/day at intervals of less than 4 hours have been used, but are generally not recommended.
Conversion from IMMEDIATE-RELEASE levodopa with or without a decarboxylase inhibitor:
  • For patients receiving levodopa with a decarboxylase inhibitor: Dosage with Sinemet CR should be approximately 10% higher than previous levodopa dosage; this may need to be increased to up to 30% higher depending on clinical response.
  • For patients receiving levodopa without a decarboxylase inhibitor: Dosage with sustained release should be approximately 25% of previous levodopa dosage; levodopa should be discontinued at least 12 hours before starting carbidopa-levodopa

Extended-Release Capsules (RYTARY):
  • Initial dose (levodopa-naive): 23.75 mg-95 mg orally 3 times a day for 3 days; on the fourth day, may increase to 36.25 mg-145 mg 3 times a day
  • Dosing interval may be increased up to a maximum of 5 times a day, if tolerated
  • Maximum daily dose: 612.5 mg-2450 mg
Conversion from IMMEDIATE-RELEASE carbidopa-levodopa to RYTARY: These recommended starting doses should be divided and given 3 times a day:
  • For patients receiving levodopa 400 to 549 mg/day: RYTARY levodopa dose should be 855 mg/day
  • For patients receiving levodopa 550 to 749 mg/day: RYTARY levodopa dose should be 1140 mg/day
  • For patients receiving levodopa 750 to 949 mg/day: RYTARY levodopa dose should be 1305 mg/day
  • For patients receiving levodopa 950 to 1249 mg/day: RYTARY levodopa dose should be 1755 mg/day
  • For patients receiving levodopa equal or greater than 1250 mg/day: RYTARY levodopa dose should be 2205 or 2340 mg/day

  • Peripheral dopa decarboxylase is saturated by carbidopa at approximately 70 to 100 mg/day; patient's receiving less than this amount of carbidopa are more likely to experience nausea and vomiting; experience with carbidopa doses greater than 200 mg/day is limited.
  • RYTARY products are not interchangeable with other carbidopa-levodopa products; for patients receiving carbidopa-levodopa plus catechol-O-methyl transferase (COMT) inhibitors, the initial recommended total daily dose of levodopa may need to be increased.

Use: For the treatment of the symptoms of idiopathic Parkinson's disease, postencephalitic parkinsonism, and symptomatic parkinsonism which may follow injury to the nervous system by carbon monoxide intoxication and/or manganese intoxication.

DUOPA Enteral Suspension (carbidopa 4.63 mg-levodopa 20 mg per mL) is indicated for the treatment of motor fluctuations in patients with advanced Parkinson's disease.
  • Administered into the jejunum through a PEG-J tube using a CADD-Legacy 1400 portable infusion pump; for short term administration, a naso-jejunal tube may be used.
  • Total dose is composed of 3 individually adjusted doses: the MORNING bolus dose, the CONTINUOUS maintenance dose, and EXTRA BOLUS doses.

Initiation: Convert all forms of levodopa to oral immediate-release carbidopa-levodopa tablets using 1:4 ratio tablets.
  • Day 1 morning dose: Provide a dose of levodopa equivalent to previous day's first levodopa dose; calculate by converting levodopa dose from mg to milliliters and add 3 milliliters of volume to prime the intestinal tube; administer over 10 to 30 minutes.
  • Day 1 continuous dose: Provide levodopa dose necessary for 16 waking hours; calculate by determining the amount of levodopa received the previous day, omitting the morning and night dose.
  • Extra bolus dose function is available to manage acute "off" symptoms; initially it should be set to 20 mg (1 mL), may titrate in 0.2 mL increments; extra doses should be limited to once every 2 hours.
Adjust doses based on clinical response:
MORNING DOSE is administered rapidly (over 10 to 30 minutes) to achieve a therapeutic dose level; this dose should be adjusted if there is an inadequate clinical response within 1 hour of the morning dose on the preceding day:
  • For doses less than or equal to 6 mL (excluding the 3 mL to prime the tube): increase by 1 mL.
  • For doses greater than 6 mL (excluding the 3 mL to prime the tube): increase by 2 mL.
  • If dyskinesia or levodopa-related adverse reactions occur within 1 hour of the morning dose on the preceding day, decrease morning dose by 1 mL.
  • Consider increasing the dose based on the number and volume of extra doses provided on the previous day and the patient's clinical response.
  • Consider decreasing the dose for troublesome dyskinesia or other adverse reactions; for reactions lasting for a period of 1 hour or more decrease by 0.3 mL/hr; for reactions lasting for periods of 2 hours or more decrease by 0.6 mL/hr.
MAXIMUM DOSE: 1 cassette (levodopa 2000 mg) over 16 hours; patient will take their night-time dose of oral immediate-release carbidopa-levodopa.

Renal Dose Adjustments

Use with caution.

Liver Dose Adjustments

Use with caution.

Dose Adjustments

When initiating this drug, administration of other standard antiparkinsonian drugs may continue; however, dose adjustments of these drugs may be needed.

RYTARY (carbidopa-levodopa extended-release capsule) is not interchangeable with other carbidopa-levodopa products.


Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.


Data not available.

Other Comments

Administration advice:
Oral Disintegrating Tablets:

  • Remove tablet from bottle with dry hands just prior to administration
  • Place on tongue, then swallow with saliva; administration of liquid is not necessary

Sinemet CR(R) Tablets:
  • Swallow whole; do not crush or chew

Rytary(R) Extended-Release Capsules:
  • Swallow whole; may also sprinkle the contents of the capsule onto 1 to 2 tablespoons of applesauce and take immediately.
  • Consider taking the first dose of the day 1 to 2 hours prior to eating; high-fat, high calorie meals may delay absorption of levodopa up to 2 to 3 hours.

Intestinal Suspension (DUOPA):
  • Cassettes should be brought to room temperature prior to use; see product information for complete administration instructions.
  • Cassettes are specifically designed to be connected to the CADD(R) Legacy 1400 pump.
  • Cassettes are for single-use only, do not use for longer than 16 hours

Storage requirements: DUOPA Cassettes:
  • Store in freezer at -20C (-4F) prior to dispensing
  • Upon dispensing, cassettes should be fully thawed in refrigerator at 2C to 8C (36F to 46F); take cartons out of transport box and separate from each other to allow even thawing (thawing may take up to 96 hours); once thawed, cartons may be repacked in a closer configuration.
  • Assign a 12-week use by date once placed in refrigerator to thaw.
  • Cassettes should be protected from light and kept in carton prior to use.

  • Stable for 24 months at -20C and 15 weeks at 5C; 16 hours once outside the refrigerator.

  • This drug is indicated for the treatment of idiopathic parkinsonism, it is useful in relieving many of the symptoms particularly rigidity and bradykinesia; it is frequently helpful in the management of tremor, dysphagia, sialorrhea, and postural instability.
  • The addition of carbidopa to levodopa will reduce the peripheral effects of levodopa; however, since carbidopa does not cross the blood brain barrier, the adverse reactions due to the central effects may occur sooner and at lower doses than levodopa alone.
  • Avoid sudden discontinuation or rapid dose reduction of this drug.
  • Because levodopa competes with certain amino acids for gut wall transport, the absorption of levodopa may be decreased in patients on high-protein diets.

  • Cardiovascular: Monitor for signs and symptoms of orthostatic hypotension, particularly during dose escalation; for patients with a history of myocardial infarction with residual atrial, nodal, or ventricular arrhythmias, cardiac function should be monitored in an intensive cardiac care facility during drug initiation.
  • Nervous System: Monitor for dyskinesias, somnolence and drowsiness
  • Dermatologic: Monitor for melanomas; consider periodic skin examinations by dermatologists.
  • Ocular: Monitor intraocular pressure in patients with chronic wide-angle glaucoma closely during therapy; blepharospasm is a useful early sign of excess dose in some patients.
  • Psychiatric: Question patients about new or increased gambling urges, sexual urges, uncontrolled spending, binge or compulsive eating, or other urges; monitor for new or worsening mental status and behavioral changes.
  • Laboratory: During chronic therapy, periodic evaluations of hepatic, hematopoietic, and renal function are recommended.

Patient advice:
  • Tell patients that this drug may cause a brownish orange discoloration in saliva, urine, or sweat; may discolor their garments.
  • This drug frequently causes drowsiness; patients should not drive a car or operate machinery or other potentially dangerous activities until it is determined how this drug affects their mental and/or motor performance; for patients who experience continued drowsiness, they should discuss with their physician the safety of driving.
  • Patients or caregivers should be instructed to report episodes of sudden onset of sleep, new or worsening dyskinesia, new or worsening compulsive behaviors and/or unusual urges, suicide attempts or suicidal ideation.
  • Patients should be instructed to report changes in the size, shape, or color of moles on their skin and should have their skin checked on a regular basis for melanomas.
  • Patients should be aware that this drug may cause orthostatic blood pressure changes including fainting and dizziness and patients are advised to avoid standing rapidly after sitting or lying down.
  • Patients should speak to their physician or health care provider if they become pregnant, intend to become pregnant, or are breastfeeding.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.