Final answer:
Carbidopa levodopa is a key medication used to manage symptoms of Parkinson's disease by increasing dopamine in the brain and compensating for neuronal loss. It works more effectively when combined with an enzyme inhibitor to prevent peripheral degradation. While helpful, its effectiveness can diminish over time and it may cause serious side effects.
Step-by-step explanation:
Carbidopa levodopa (also known as Sinemet) is a medication commonly prescribed for the management of Parkinson's disease, a neurodegenerative disorder. Since there is no cure for Parkinson's treatments such as L-DOPA aim to increase dopamine neurotransmission in the brain, and help compensate for the loss of dopaminergic neurons in the substantia nigra. When L-DOPA is administered it must cross the blood-brain barrier to be converted to dopamine by the remaining neural cells.
However this conversion can also occur outside the brain, causing unwanted side effects and reducing the efficacy of the treatment. Carbidopa is included with levodopa to inhibit the enzyme that breaks down dopamine outside the brain, thereby increasing the content loaded with levodopa available to cross the blood-brain barrier. While effective patients may become less responsive to levodopa treatment over time and elevated levels of dopamine in other brain areas can result in side effects such as psychosis or schizophrenia. Other classes of drugs, like monoamine oxidase inhibitors are also used to prevent the degradation of neurotransmitters but can have toxic effects and dangerous interactions, making them less commonly prescribed.