Vexdopa Dosage/Direction for Use

The optimum daily dosage Carbidopa-Levodopa must be determined by careful titration in each patient. Levodopa-carbidopa tablets are available in a 1:10. 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.
How to Transfer Patients from Levodopa: Levodopa must be discontinued at least twelve hours before starting Carbidopa-Levodopa. A daily dosage of Carbidopa-Levodopa 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-Levodopa 25-100 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-Levodopa 25mg + 100mg 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-Levodopa 25mg + 100mg may be substituted for each tablet of Carbidopa-Levodopa 1 0mg+ 100mg. If necessary, the dosage of Carbidopa-Levodopa 25mg + 100mg 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-Levodopa than with levodopa alone, patients should be monitored closely during the dose adjustment period. Specifically, involuntary movements will occur more rapidly with Carbidopa-Levodopa 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.
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-Levodopa 25mg + 100mg may be substituted for each tablet of Carbidopa-Levodopa 10mg+100mg. When more levodopa is required, Levodopa 25mg + 100mg should be substituted for Carbidopa-Levodopa 25mg + 100mg or Levodopa 100mg+100mg. If necessary, the dosage of Carbidopa-Levodopa 25mg + 100mg 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-Levodopa 25mg + 100mg than with levodopa alone, patients should be monitored closely during the dose adjustment period. Specifically, involuntary movements will occur more rapidly with Carbidopa-Levodopa 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-Levodopa is being administered, although dosage adjustments may be required.
Interruption of Therapy: Sporadic cases of a symptom complex resembling Neuroleptic Malignant Syndrome (NMS) have been associated with dose reductions and withdrawal of Carbidopa-Levodopa. Patients should be observed carefully if abrupt reduction or discontinuation of Carbidopa-Levodopa is required, especially if the patient is receiving neuroleptics. (See Warnings.)