Parkinsonism and Parkinson's Disease Overview

A medication used to treat Parkinson's disease by increasing dopamine levels in the brain.

A medication used to treat Parkinson's disease that prevents the breakdown of levodopa, increasing its effectiveness.

A combination of levodopa and carbidopa, often used to treat Parkinson's disease.

Involuntary movements, especially in the limbs, that can occur as a side effect of levodopa treatment.

A dopamine agonist medication used to treat Parkinson's disease.

Dopamine receptor agonists that are not based on the ergot molecule.

A non-ergot dopamine agonist used to treat Parkinson's disease.

A non-ergot dopamine agonist used to treat Parkinson's disease.

Levodopa is ineffective in healthy individuals or patients with other neurological conditions, but provides significant improvement in symptoms of Parkinson's disease.

Symptoms like hypokinesia and rigidity improve first, followed by tremor, indicating a gradual restoration of movement control.

Levodopa's positive effects on posture, gait, handwriting, speech, facial expressions, mood, and overall well-being gradually normalize as the treatment progresses.

Levodopa's therapeutic benefits are most pronounced in the early stages of Parkinson's disease but gradually diminish as the disease advances.

Levodopa's overall effect can be described as a ‘general alerting response’, improving alertness and overall cognitive function.

Levodopa's conversion to dopamine in the periphery can lead to side effects like nausea and vomiting.

Levodopa can cause postural hypotension due to a decrease in sympathetic outflow and DA's action on autonomic ganglia. Tolerance develops over time.

Dopaminergic receptors in the chemoreceptor trigger zone (CTZ) are stimulated by dopamine, leading to nausea and vomiting. Tolerance develops gradually.

A class of drugs that inhibit the enzyme monoamine oxidase type B (MAO-B). MAO-B breaks down dopamine, a neurotransmitter important for movement. Inhibiting MAO-B increases dopamine levels, which can help improve symptoms of Parkinson's disease.

A type of MAO-B inhibitor used to treat Parkinson's disease. It is given twice a day and can be used alone in early stages or with levodopa/carbidopa in later stages.

A newer MAO-B inhibitor with similar effects to selegiline but with a longer duration of action and is given only once a day.

Drugs that block the enzyme catechol-o-methyltransferase (COMT). COMT breaks down levodopa, a medication used to treat Parkinson's disease, before it can reach the brain. Blocking COMT allows more levodopa to reach the brain and improve symptoms.

A commonly used COMT inhibitor, taken with each dose of levodopa/carbidopa. It helps improve efficacy of levodopa.

A COMT inhibitor with a stronger effect than entacapone, but its use is restricted due to potential side effects like liver damage.

A type of receptor in the brain that is involved in regulating the release of dopamine. Blocking NMDA receptors can help increase dopamine levels and improve symptoms of Parkinson's disease.

Drugs that block the NMDA receptor. This can help facilitate dopamine release, leading to improvement in Parkinson's symptoms.

Amantadine, initially an antiviral drug, was unexpectedly found to improve Parkinson's symptoms.

COMT inhibitors like Entacapone and Tolcapone are used alongside levodopa to enhance its effects in advanced Parkinson's disease.

Entacapone and Tolcapone block COMT, an enzyme that breaks down levodopa, allowing more levodopa to reach the brain.

Amantadine improves Parkinson's symptoms by promoting dopamine release and acting as an anticholinergic, but its most significant effect is likely through blocking NMDA receptors.

Amantadine can be used for milder Parkinson's cases, or in short bursts to manage fluctuations in advanced cases.

COMT inhibitors primarily act on the periphery, with limited central effects, while dopamine is broken down in both the periphery and the brain.

Carbidopa and benserazide are medications used to prevent levodopa breakdown in the periphery, allowing more of it to reach the brain.

Amantadine's efficacy in Parkinson's gradually decreases over time due to tolerance development.

A type of medication used to treat Parkinson's disease. It works by mimicking dopamine's action in the brain, helping to improve movement and coordination. It is longer acting than levodopa and can help manage motor fluctuations and reduce the frequency of "on-off" effects.

A type of side effect experienced by some individuals taking dopamine agonists, characterized by unpredictable fluctuations in motor symptoms or medication response. This often leads to a 'on' state (good control) and an 'off' state (worse symptoms) in individuals with Parkinson's disease.

A common side effect of dopamine agonists that can disrupt a person's sleep patterns, making them feel excessively sleepy during the day.

A common side effect of dopamine agonists characterized by a sudden drop in blood pressure when standing up, leading to dizziness or lightheadedness.

A type of medication that inhibits the breakdown of dopamine in the brain, leading to increased dopamine levels. It acts as an adjunct to levodopa therapy in Parkinson's disease, prolonging the duration of action and potentially reducing side effects.

A common side effect of dopamine agonists that can be distressing, characterized by seeing or hearing things that aren't real. It can be more common in individuals with Parkinson's disease and may affect their quality of life.

The basal ganglia's primary role is to fine-tune motor control, balancing excitatory and inhibitory signals to produce smooth, coordinated movements. It helps reduce involuntary movements known as muscle tone, ensuring efficient and controlled motor output.

In Parkinson's disease, the degeneration of dopamine-producing cells in the substantia nigra disrupts the balance between dopamine and acetylcholine in the striatum, leading to a decrease in motor activity and the development of rigidity, tremors, and hypokinesia.

Levodopa, a precursor to dopamine, is rapidly absorbed from the small intestine. It utilizes the same transport system as other aromatic amino acids, but its bioavailability is affected by factors like gastric emptying speed and competition from other amino acids in food.

Levodopa's absorption rate can be affected by gastric emptying rate. Slow emptying increases the time Levodopa spends in the gut, exposing it to degrading enzymes and reducing its availability to reach the brain.

The active transport system for Levodopa absorption can be hindered by other amino acids present in food. This competition reduces Levodopa's uptake into the bloodstream.

Levodopa undergoes a significant first-pass metabolism in the gut and liver. This means a large portion of the drug is metabolized before it reaches the bloodstream, affecting its bioavailability.

Common side effects of Levodopa therapy include nausea, vomiting, and involuntary movements. Starting with a low dose and gradually increasing it can minimize these side effects.

Initially, patients often experience nausea and vomiting during Levodopa therapy. However, tolerance to these side effects usually develops over time, allowing for dose increases.