Sinemet 25/100/Sinemet 25/250 Special Precautions

Sinemet may be given to patients already receiving levodopa alone; however, the levodopa alone must be discontinued at least 12 hrs before Sinemet is started. Sinemet should be substituted at a dosage that will provide approximately 20% of the previous levodopa dosage (see Dosage & Administration).
Sinemet is not recommended for the treatment of drug-induced extrapyramidal reactions.
Sinemet should be administered cautiously to patients with severe cardiovascular or pulmonary disease, bronchial asthma, renal, hepatic or endocrine disease.
As with levodopa, care should be exercised in administering Sinemet to patients with a history of myocardial infarction who have atrial, nodal or ventricular arrhythmia. In such patients, cardiac function should be monitored with particular care during the period of initial dosage adjustment.
All patients should be monitored carefully for the development of mental changes, depression with suicidal tendencies, or other serious antisocial behavior.
As with levodopa, Sinemet may cause involuntary movements and mental disturbances. Patients with current or a history of severe involuntary movements or psychotic episodes should be monitored carefully. These reactions are thought to be due to increased brain dopamine.
A symptom complex resembling the neuroleptic malignant syndrome including muscular rigidity, elevated body temperature, mental changes and increased serum creatine phosphokinase has been reported when antiparkinsonian agents were withdrawn abruptly. Therefore, patients should be observed carefully when the dosage of Sinemet is reduced abruptly or discontinued, especially if the patient is receiving neuroleptics.
Caution should be exercised with concomitant administration of psychoactive drugs and Sinemet (see Interactions). Patients with a history of convulsion should be treated with caution.
Patients with chronic wide-angle glaucoma may be treated cautiously with Sinemet, provided the intraocular pressure is well controlled and the patient monitored carefully for changes in intraocular pressure during therapy.
As with levodopa, there is a possibility of upper gastrointestinal hemorrhage in patients with a history of peptic ulcer.
If general anesthesia is required, Sinemet should be discontinued for at least 6-8 hrs prior to anesthetic procedure. Sinemet may be continued as long as the patient is permitted to take fluids and medication by mouth. If therapy is interrupted temporarily, the usual daily dosage may be administered as soon as the patient is able to take oral medication.
Use in pregnancy & lactation: The effects of Sinemet on human pregnancy and lactation are unknown. Both levodopa and combination of levodopa and carbidopa have caused visceral and skeletal malformation in experimental animals. Therefore, use of Sinemet during pregnancy requires that the anticipated benefits of the drug be weighed against possible hazards.
Sinemet should not be given to nursing mothers.
Use in children: The safety of Sinemet in patients <18 years has not been established.