Instructions for Use/Handling Carbidopa and Levodopa Orally Disintegrating Tablets, USP

Just prior to administration, GENTLY remove the tablet from the bottle with dry hands. IMMEDIATELY place the carbidopa and levodopa orally disintegrating tablet on top of the tongue where it will dissolve in seconds, then swallow with saliva. Administration with liquid is not necessary.

The optimum daily dosage of carbidopa and levodopa orally disintegrating tablets must be determined by careful titration in each patient. Carbidopa and levodopa orally disintegrating tablets are available in a 1:4 ratio of carbidopa to levodopa (carbidopa and levodopa orally disintegrating tablets 25 mg/100 mg) as well as 1:10 ratio (carbidopa and levodopa orally disintegrating tablets 25 mg/250 mg and carbidopa and levodopa orally disintegrating tablets 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 orally disintegrating tablets 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 orally disintegrating tablets 25 mg/100 mg a day is reached.

If carbidopa and levodopa orally disintegrating tablet 10 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 orally disintegrating tablets. A daily dosage of carbidopa and levodopa orally disintegrating 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 orally disintegrating tablets 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 orally disintegrating tablets 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 orally disintegrating tablets 25 mg/100 mg may be substituted for each tablet of carbidopa and levodopa orally disintegrating tablets 10 mg/100 mg. When more levodopa is required, carbidopa and levodopa orally disintegrating tablets 25 mg/250 mg should be substituted for carbidopa and levodopa orally disintegrating tablets 25 mg/100 mg or carbidopa and levodopa orally disintegrating tablets 10 mg/100 mg. If necessary, the dosage of carbidopa and levodopa orally disintegrating tablets 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 orally disintegrating 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 orally disintegrating 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 orally disintegrating tablet is 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. Patients should be observed carefully if abrupt reduction or discontinuation of carbidopa and levodopa orally disintegrating tablets is required, especially if the patient is receiving neuroleptics. (See WARNINGS.)

If general anesthesia is required, carbidopa and levodopa orally disintegrating 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.