Carbidopa and Levodopa

Carbidopa and Levodopa
Adult Indications & Dosage
Pediatric Indications & Dosage
Contraindications
Warnings & Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Administration & Monitoring
Overdosage
Pharmacology
Clinical Studies
How Supplied
Images
Patient Counseling Information
Precautions with Alcohol
Brand Names
Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Deepika Beereddy, MBBS [2]

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Overview

Carbidopa and Levodopa is an immunologic adjuvant that is FDA approved for the treatment of parkinson's disease, post-encephalitic parkinsonism, and symptomatic parkinsonism. Common adverse reactions include nausea, confusion, dizziness, headache.

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

Parkinson's disease

• Carbidopa and levodopa tablets, USP are indicated in the treatment of Parkinson's disease, post-encephalitic parkinsonism, and symptomatic parkinsonism that may follow carbon monoxide intoxication or manganese intoxication.

• Carbidopa allows patients treated for Parkinson's disease to use much lower doses of levodopa. Some patients who responded poorly to levodopa have improved on carbidopa and levodopa tablets.. This is most likely due to decreased peripheral decarboxylation of levodopa caused by administration of carbidopa rather than by a primary effect of carbidopa on the nervous system. Carbidopa has not been shown to enhance the intrinsic efficacy of levodopa.

• Carbidopa may also reduce nausea and vomiting and permit more rapid titration of levodopa.

• Dosing information:

• The optimum daily dosage of carbidopa and levodopa tablets must be determined by careful titration in each patient. Carbidopa and levodopa tablets are available in a 1:4 ratio of carbidopa to levodopa (carbidopa and levodopa tablets, USP 25 mg/100 mg) as well as 1:10 ratio (carbidopa and levodopa tablets, USP 25 mg/250 mg and carbidopa and levodopa tablets, USP 10 mg/100 mg). Tablets of the two ratios may be given separately or combined as needed to provide the optimum dosage.

• Studies show that peripheral dopa decarboxylase is saturated by carbidopa at approximately 70 to 100 mg a day. Patients receiving less than this amount of carbidopa are more likely to experience nausea and vomiting.

• Usual Initial Dosage

• Dosage is best initiated with one tablet of carbidopa and levodopa 25 mg/100 mg three times a day. This dosage schedule provides 75 mg of carbidopa per day. Dosage may be increased by one tablet every day or every other day, as necessary, until a dosage of eight tablets of carbidopa and levodopa 25 mg/100 mg a day is reached.

• If carbidopa and levodopa tablets10 mg/100 mg is used, dosage may be initiated with one tablet three or four times a day. However, this will not provide an adequate amount of carbidopa for many patients. Dosage may be increased by one tablet every day or every other day until a total of eight tablets (2 tablets q.i.d.) is reached.

• How to Transfer Patients from Levodopa

• Levodopa must be discontinued at least twelve hours before starting carbidopa and levodopa tablets. A daily dosage of carbidopa and levodopa tablets should be chosen that will provide approximately 25% of the previous levodopa dosage. Patients who are taking less than 1500 mg of levodopa a day should be started on one tablet of carbidopa and levodopa 25 mg/100 mg three or four times a day. The suggested starting dosage for most patients taking more than 1500 mg of levodopa is one tablet of carbidopa and levodopa 25 mg/250 mg three or four times a day.

• Maintenance

• Therapy should be individualized and adjusted according to the desired therapeutic response. At least 70 to 100 mg of carbidopa per day should be provided. When a greater proportion of carbidopa is required, one tablet of carbidopa and levodopa 25 mg/100 mg may be substituted for each tablet of carbidopa and levodopa 10 mg/100 mg. When more levodopa is required, carbidopa and levodopa 25 mg/250 mg should be substituted for carbidopa and levodopa 25 mg/100 mg or carbidopa and levodopa 10 mg/100 mg. If necessary, the dosage of carbidopa and levodopa 25 mg/250 mg may be increased by one-half or one tablet every day or every other day to a maximum of eight tablets a day. Experience with total daily dosages of carbidopa greater than 200 mg is limited.

• Because both therapeutic and adverse responses occur more rapidly with carbidopa and levodopa tablets than with levodopa alone, patients should be monitored closely during the dose adjustment period. Specifically, involuntary movements will occur more rapidly with carbidopa and levodopa tablets than with levodopa. The occurrence of involuntary movements may require dosage reduction. Blepharospasm may be a useful early sign of excess dosage in some patients.

• Addition of Other Antiparkinsonian Medications

• Standard drugs for Parkinson's disease, other than levodopa without a decarboxylase inhibitor, may be used concomitantly while carbidopa and levodopa tablets are being administered, although dosage adjustments may be required.

• Interruption of Therapy

• Sporadic cases of hyperpyrexia and confusion have been associated with dose reductions and withdrawal of carbidopa and levodopa tablets. Patients should be observed carefully if abrupt reduction or discontinuation of carbidopa and levodopa tablets is required, especially if the patient is receiving neuroleptics.

• If general anesthesia is required, carbidopa and levodopa tablets may be continued as long as the patient is permitted to take fluids and medication by mouth. If therapy is interrupted temporarily, the patient should be observed for symptoms resembling NMS, and the usual daily dosage may be administered as soon as the patient is able to take oral medication.

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Carbidopa and Levodopa in adult patients.

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Carbidopa and Levodopa in adult patients.

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

There is limited information regarding Carbidopa and Levodopa FDA-Labeled Indications and Dosage (Pediatric) in the drug label.

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Carbidopa and Levodopa in pediatric patients.

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Carbidopa and Levodopa in pediatric patients.

Contraindications

There is limited information regarding Carbidopa and Levodopa Contraindications in the drug label.

Warnings

There is limited information regarding Carbidopa and Levodopa Warnings' in the drug label.

Adverse Reactions

Clinical Trials Experience

There is limited information regarding Carbidopa and Levodopa Clinical Trials Experience in the drug label.

Postmarketing Experience

There is limited information regarding Carbidopa and Levodopa Postmarketing Experience in the drug label.

Drug Interactions

There is limited information regarding Carbidopa and Levodopa Drug Interactions in the drug label.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): There is no FDA guidance on usage of Carbidopa and Levodopa in women who are pregnant.
Pregnancy Category (AUS): There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Carbidopa and Levodopa in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Carbidopa and Levodopa during labor and delivery.

Nursing Mothers

There is no FDA guidance on the use of Carbidopa and Levodopa in women who are nursing.

Pediatric Use

There is no FDA guidance on the use of Carbidopa and Levodopa in pediatric settings.

Geriatic Use

There is no FDA guidance on the use of Carbidopa and Levodopa in geriatric settings.

Gender

There is no FDA guidance on the use of Carbidopa and Levodopa with respect to specific gender populations.

Race

There is no FDA guidance on the use of Carbidopa and Levodopa with respect to specific racial populations.

Renal Impairment

There is no FDA guidance on the use of Carbidopa and Levodopa in patients with renal impairment.

Hepatic Impairment

There is no FDA guidance on the use of Carbidopa and Levodopa in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Carbidopa and Levodopa in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Carbidopa and Levodopa in patients who are immunocompromised.

Administration and Monitoring

Administration

There is limited information regarding Carbidopa and Levodopa Administration in the drug label.

Monitoring

There is limited information regarding Carbidopa and Levodopa Monitoring in the drug label.

IV Compatibility

There is limited information regarding the compatibility of Carbidopa and Levodopa and IV administrations.

Overdosage

There is limited information regarding Carbidopa and Levodopa overdosage. If you suspect drug poisoning or overdose, please contact the National Poison Help hotline (1-800-222-1222) immediately.

Pharmacology

There is limited information regarding Carbidopa and Levodopa Pharmacology in the drug label.

Mechanism of Action

There is limited information regarding Carbidopa and Levodopa Mechanism of Action in the drug label.

Structure

• Carbidopa and levodopa tablets, USP are a combination of carbidopa and levodopa for the treatment of Parkinson's disease and syndrome.

• Carbidopa, an inhibitor of aromatic amino acid decarboxylation, is a white to yellowish white, crystalline compound or creamy white powder, slightly soluble in water, with a molecular weight of 244.24. It is designated chemically as (-)-L-α-hydrazino-α-methyl-β-(3,4-dihydroxybenzene) propanoic acid monohydrate. Its molecular formula is C10H14N2O4•H20, and its structural formula is:

Pharmacodynamics

There is limited information regarding Carbidopa and Levodopa Pharmacodynamics in the drug label.

Pharmacokinetics

There is limited information regarding Carbidopa and Levodopa Pharmacokinetics in the drug label.

Nonclinical Toxicology

There is limited information regarding Carbidopa and Levodopa Nonclinical Toxicology in the drug label.

Clinical Studies

There is limited information regarding Carbidopa and Levodopa Clinical Studies in the drug label.

How Supplied

There is limited information regarding Carbidopa and Levodopa How Supplied in the drug label.

Storage

There is limited information regarding Carbidopa and Levodopa Storage in the drug label.

Images

Drug Images

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Package and Label Display Panel

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Patient Counseling Information

There is limited information regarding Carbidopa and Levodopa Patient Counseling Information in the drug label.

Precautions with Alcohol

Alcohol-Carbidopa and Levodopa interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

There is limited information regarding Carbidopa and Levodopa Brand Names in the drug label.

Look-Alike Drug Names

There is limited information regarding Carbidopa and Levodopa Look-Alike Drug Names in the drug label.

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.