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Pronunciation |
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(kar
bi DOE
pa) |
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U.S. Brand
Names |
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Lodosyn® |
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Generic
Available |
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No |
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Pharmacological Index |
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Anti-Parkinson's Agent (Dopamine Agonist) |
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Use |
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Given with levodopa in the treatment of parkinsonism to enable a lower dosage
of levodopa to be used and a more rapid response to be obtained and to decrease
side-effects; for details of administration and dosage, see Levodopa; has no
effect without levodopa |
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Pregnancy Risk
Factor |
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C |
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Contraindications |
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Hypersensitivity to carbidopa or levodopa |
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Adverse
Reactions |
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Adverse reactions are associated with concomitant administration with
levodopa
1% to 10%:
Cardiovascular: Orthostatic hypotension, palpitations, cardiac arrhythmias
Central nervous system: Memory loss, nervousness, insomnia, fatigue,
hallucinations, ataxia, dystonic movements
Gastrointestinal: Nausea, vomiting, GI bleeding
Ocular: Blurred vision
<1%: Hypertension, duodenal ulcer, hemolytic anemia |
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Drug
Interactions |
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Increased toxicity: Tricyclic antidepressant
hypertensive reactions and dyskinesia |
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Mechanism of
Action |
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Carbidopa is a peripheral decarboxylase inhibitor with little or no
pharmacological activity when given alone in usual doses. It inhibits the
peripheral decarboxylation of levodopa to dopamine; and as it does not cross the
blood-brain barrier, unlike levodopa, effective brain concentrations of dopamine
are produced with lower doses of levodopa. At the same time, reduced peripheral
formation of dopamine reduces peripheral side-effects, notably nausea and
vomiting, and cardiac arrhythmias, although the dyskinesias and adverse mental
effects associated with levodopa therapy tend to develop
earlier. |
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Pharmacodynamics/Kinetics |
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Absorption: Rapid but incomplete from GI tract
Distribution: Does not cross the blood-brain barrier; in rats, it has been
reported to cross the placenta and to be excreted in milk
Elimination: Rapidly excreted in urine both unchanged and in the form of
metabolites |
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Usual Dosage |
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Adults: Oral: 70-100 mg/day; maximum daily dose: 200 mg |
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Dietary
Considerations |
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May be administered with meals to decrease GI upset |
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Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
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No information available to require special precautions |
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Dental Health:
Effects on Dental Treatment |
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Dopaminergic therapy in Parkinson's disease includes the use of carbidopa in
combination with levodopa. Carbidopa/levodopa combination is associated with
orthostatic hypotension. Patients medicated with this drug combination should be
carefully assisted from the chair and observed for signs of orthostatic
hypotension. |
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Patient
Information |
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Can take with food to prevent GI upset, do not stop taking this drug even if
you do not think it is working; dizziness, lightheadedness, fainting may occur
when getting up from a sitting or lying position |
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Dosage Forms |
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Tablet: 25 mg |
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