Home » Drug Information » FDA Approved Drugs » 1999
Medical Areas: Neurology | Family Medicine
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The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Approval Status: October 19, 1999
Treatment Area: For Parkinson's patients being treated with levodopa therapy who experience end-of-dose "wearing off"
This new treatment in the management of idiopathic
Parkinson's Disease helps prolong the effects of the
levodopa/carbidopa preparations, such as improved motor performance
and increased amounts of "on" time (periods of good
function and mobility in which a patient is able to perform common
daily activities such as walking, speaking, and writing).
Comtan belongs to a class of therapeutic treatments called COMT
inhibitors which block the COMT enzyme. When taken with the
prescribed levodopa/carbidopa treatment, the inhibitor reduces the
breakdown of levodopa before it reaches the brain. As a result, the
effects of each levodopa dose are extended and enhanced.
The effects of Comtan were tested on nearly 700 patients in
worldwide, multi-center trials. Compared to a placebo, patients
with Parkinson's who took Comtan demonstrated improved motor
performance and had significantly increased amounts of
"on" time each day. Several important Phase III studies
indicated that the benefits were salient for patients who showed
deteriorating response to levodopa/carbidopa, particularly in
important activities of daily living such as speaking, handwriting,
walking and dressing.
Comtan is generally well-tolerated and doesn't require any
specific safety monitoring. The most commonly reported side-effects
were dyskinesia, nausea, diarrhea, abdominal pain and urine
discoloration. A very small percentage of participants in the
trials also experienced hallucinations. Dopaminergic side effects
like dyskinesia often improved after adjustment of the levodopa
Mechanism of Action
Entacapone inhibits COMT and alters the plasma pharmokinetics of
levodopa. When entacapone is given in conjunction with levodopa and
an aromatic amino acid decarboxylase inhibitor, such as carbidopa,
plasma levels of levodopa are greater and more sustained than after
administration of levodopa and an aromatic amino acid decarboxylase
inhibitor alone. It is believed that at a given frequency of
levodopa administration, these more sustained plasma levels of
levodopa result in more constant dopaminergic stimulation in the
brain, leading to greater effects on the signs and symptoms of
Parkinson's disease. The higher levodopa levels also lead to
increased levodopa adverse effects, sometimes requiring a decrease
in the dose of levodopa. (FDA Label)
For more information about Comtan, call 1-888-669-6682.
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