Dosage of Carbidopa/levodopa in details
Dosage in Patients Naïve to Levodopa Therapy
The recommended starting dosage of Carbidopa/levodopa in levodopa-naïve patients is 23.75 mg / 95 mg taken orally three times a day for the first 3 days. On the fourth day of treatment, the dosage of Carbidopa/levodopa may be increased to 36.25 mg / 145 mg taken three times a day.
Based upon individual patient clinical response and tolerability, the Carbidopa/levodopa dose may be increased up to a maximum recommended dose of 97.5 mg / 390 mg taken three times a day. The dosing frequency may be changed from three times a day to a maximum of five times a day if more frequent dosing is needed and if tolerated. The maximum recommended daily dose of Carbidopa/levodopa is 612.5 mg / 2450 mg.
Maintain patients on the lowest dosage required to achieve symptomatic control and to minimize adverse reactions such as dyskinesia and nausea.
Converting from Immediate-Release Carbidopa-Levodopa to Carbidopa/levodopa
To convert patients from immediate-release carbidopa-levodopa to Carbidopa/levodopa, determine the recommended starting dosage of Carbidopa/levodopa using Table 1.
The dosages of other carbidopa and levodopa products are not interchangeable with the dosages of Carbidopa/levodopa.
Adjust the dose to maintain patient tolerance and sufficient symptomatic control. The dosing frequency may be changed from three times a day to a maximum of five times a day if more frequent dosing is needed and if tolerated. The maximum recommended daily dose of Carbidopa/levodopa is 612.5 mg / 2450 mg.
For patients currently treated with carbidopa and levodopa plus catechol-O-methyl transferase (COMT) inhibitors (such as entacapone), the initial total daily dose of levodopa in Carbidopa/levodopa described in Table 1 may need to be increased.
Use of Carbidopa/levodopa in combination with other levodopa products has not been studied.
| Total Daily Dose of Levodopa in Immediate-Release Carbidopa-Levodopa | Recommended Starting Dosage of Carbidopa/levodopa | |
|---|---|---|
| Total Daily Dose of Levodopa in Carbidopa/levodopa | Carbidopa/levodopa Dosing Regimen | |
| ||
| 400 mg to 549 mg | 855 mg | 3 capsules Carbidopa/levodopa 23.75 mg / 95 mg taken TID* |
| 550 mg to 749 mg | 1140 mg | 4 capsules Carbidopa/levodopa 23.75 mg / 95 mg taken TID |
| 750 mg to 949 mg | 1305 mg | 3 capsules Carbidopa/levodopa 36.25 mg / 145 mg taken TID |
| 950 mg to 1249 mg | 1755 mg | 3 capsules Carbidopa/levodopa 48.75 mg / 195 mg taken TID |
| Equal to or greater than 1250 mg | 2340 mg or | 4 capsules Carbidopa/levodopa 48.75 mg / 195 mg taken TID or |
| 2205 mg | 3 capsules Carbidopa/levodopa 61.25 mg / 245 mg taken TID | |
Discontinuation of Carbidopa/levodopa
Avoid sudden discontinuation or rapid dose reduction of Carbidopa/levodopa. The daily dose of Carbidopa/levodopa should be tapered at the time of treatment discontinuation.
Administration Information
Swallow Carbidopa/levodopa whole with or without food. A high-fat, high-calorie meal may delay the absorption of levodopa by about 2 hours.
Do not chew, divide or crush Carbidopa/levodopa capsules. For patients who have difficulty swallowing intact capsules, administer Carbidopa/levodopa by carefully opening the capsule, sprinkling the entire contents on a small amount of applesauce (1 to 2 tablespoons), and consuming immediately. Do not store the drug/food mixture for future use.
What other drugs will affect Carbidopa/levodopa?
Taking Carbidopa/levodopa with other drugs that make you sleepy can worsen this effect. Ask your doctor before taking Carbidopa/levodopa with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.
Tell your doctor about all your current medicines and any you start or stop using, especially:
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isoniazid;
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metoclopramide;
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blood pressure medication;
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medicines, vitamins, or mineral supplements that contain iron; or
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medicine to treat a psychiatric disorder (such as Abilify, Geodon, Risperdal, Seroquel, Symbyax, or Zyprexa).
This list is not complete. Other drugs may interact with carbidopa and levodopa, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.
Carbidopa/levodopa drug interactions (more detail)
Carbidopa/levodopa interactions
Caution should be exercised when the following drugs are administered concomitantly with Carbidopa/levodopa.
Symptomatic postural hypotension occurred when Carbidopa/levodopa was added to the treatment of a patient receiving antihypertensive drugs. Therefore, when therapy with Carbidopa/levodopa is started, dosage adjustment of the antihypertensive drug may be required.
For patients receiving MAO inhibitors (Type A or B), see CONTRAINDICATIONS. Concomitant therapy with selegiline and carbidopa levodopa may be associated with severe orthostatic hypotension not attributable to carbidopa levodopa alone.
There have been rare reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use of tricyclic antidepressants and Carbidopa/levodopa.
Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) and isoniazid may reduce the therapeutic effects of levodopa. In addition, the beneficial effects of levodopa in Parkinson's disease have been reported to be reversed by phenytoin and papaverine. Patients taking these drugs with Carbidopa/levodopa should be carefully observed for loss of therapeutic response.
Use of Carbidopa/levodopa with dopamine-depleting agents (e.g., reserpine and tetrabenazine) or other drugs known to deplete monoamine stores is not recommended.
Carbidopa/levodopa and iron salts or multivitamins containing iron salts should be coadministered with caution. Iron salts can form chelates with levodopa and carbidopa and consequently reduce the bioavailability of carbidopa and levodopa.
Although metoclopramide may increase the bioavailability of levodopa by increasing gastric emptying, metoclopramide may also adversely affect disease control by its dopamine receptor antagonistic properties.
References
- DailyMed. "CARBIDOPA; ENTACAPONE; LEVODOPA: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- FDA/SPL Indexing Data. "KR87B45RGH: The UNique Ingredient Identifier (UNII) is an alphanumeric substance identifier from the joint FDA/USP Substance Registration System (SRS).". https://www.fda.gov/ForIndustry/Data... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Carbidopa/levodopa are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Carbidopa/levodopa. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
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Information checked by Dr. Sachin Kumar, MD Pharmacology
