General: When levodopa + carbidopa is to be given to patients who are being treated with levodopa, levodopa must be discontinued at least 12 hours before therapy with levodopa + carbidopa is started. In order to reduce adverse reactions, it is necessary to individualize therapy.
As with levodopa, periodic evaluations of hepatic, hematopoietic, cardiovascular, and renal function are recommended during extended therapy.
Levodopa + carbidopa is not recommended for the treatment of medicine-induced extrapyramidal reactions.
Patients who improve while on therapy with levodopa + carbidopa should increase physical activities gradually, with caution, consistent with other medical considerations such as the presence of osteoporosis or phlebothrombosis.
Cardiovascular: Care should be exercised when giving levodopa + carbidopa to patients with a history of myocardial infarction who have residual atrial, nodal or ventricular arrhythmia. Monitoring of cardiac function should be done with particular care during the initial dosage administration and titration period.
Nervous System: Dyskinesia: Certain adverse CNS effects such as dyskinesia may occur at lower dosages sooner with levodopa + carbidopa than with levodopa alone. Dosage reduction may be necessary when dyskinesia develops.
Mental Disturbance: Patients, particularly those who have psychological problems or a medical history of such disorders, should be monitored for the development of depression and suicidal tendencies, and other serious antisocial behavior. Patients with past or current psychoses should be treated with caution.
Somnolence: Levodopa + carbidopa may cause somnolence and rare episodes of sudden onset of sleep (sleep episodes occurring without awareness or warning during daily activities). Patients should be advised to avoid performing tasks which require complete mental alertness such as driving or operating machines.
Neuroleptic Malignant Syndrome (NMS): NMS or a symptom complex resembling NMS may occur in association with dosage reductions or withdrawal of therapy with levodopa + carbidopa. Patients should be observed carefully when the dosage of levodopa + carbidopa is reduced abruptly or discontinued, particularly if the patient is receiving neuroleptics.
Although uncommon, NMS may be a life-threatening syndrome characterized by fever or hyperthermia. Neurological findings, including muscle rigidity, involuntary movements, altered consciousness, mental status changes; other disturbances, such as autonomic dysfunction, tachycardia, tachypnea, sweating, hyper- or hypotension; laboratory findings, such as creatine phosphokinase elevation, leukocytosis, myoglobinuria, and increased serum myoglobin have been reported.
Early diagnosis is important for appropriate management of NMS which should include: 1) intensive symptomatic treatment and medical monitoring, and 2) treatment of any concomitant serious medical problems for which specific treatments are available.
Behavioral Disturbances: Long-term use of levodopa and dopamine agonists has been associated with hypersexuality, punding (purposeless repetitive acts), excessive gambling or shopping, and other obsessive behavior such as compulsive eating. Healthcare professionals should inform patients to seek help from their doctor if they, their family or their caregiver notice that their behavior is unusual.
Hallucinations: Patients should be aware that hallucinations (mostly visual) can occur when undergoing treatment with dopaminergic agents, including levodopa.
Ophthalmologic: Glaucoma: Pupillary dilatation and activation of latent Horner's syndrome have been reported during levodopa treatment. Levodopa + carbidopa should be given with caution to patients with chronic wide-angle glaucoma. It is important that intraocular pressure is well-controlled and periodically monitored in these patients.
Dermatologic: Melanoma: Patients with Parkinson's disease have a higher risk (2- to approximately 6-fold higher) of developing melanoma than the general population. Periodic skin examinations should be done frequently and on a regular basis by appropriately qualified individuals(e.g., dermatologist).
Peri-Operative Considerations: In cases when general anesthesia is required, levodopa + carbidopa may be continued as long as patients are allowed to take fluids and medication orally. If treatment is interrupted temporarily, the usual daily dose may be given as soon as the patient is able to take oral medication.
Use in Patients with Concomitant Illness: Exercise caution when giving levodopa + carbidopa to patients with severe cardiovascular or pulmonary disease; bronchial asthma; renal, hepatic or
endocrine disease; history of peptic ulcer disease (because of the possibility of upper gastrointestinal hemorrhage); history of seizures, conditions associated with seizure, or have a lowered seizure threshold.
Advice for Patients: Levodopa + carbidopa should be taken at regular intervals according to the schedule outlined by the physician. Sometimes a "wearing off" effect may occur at the end of the dosing interval. The physician should be notified if such a response poses a problem to lifestyle.
Patients should be advised that occasionally, dark color (red, brown, or black) may appear in saliva, urine or sweat after taking levodopa + carbidopa. Although it appears to be clinically insignificant, garments may become discolored.
Use in Children (< 18 years old): The use of levodopa + carbidopa in patients below 18 years old is not recommended.