Parkinson's Disease Medications Quiz

Progressive neurological disorder affecting muscle movement, characterized by slowness of movement (bradykinesia), muscle rigidity, resting tremor, and abnormal gait. In late stages, it can lead to akinesia, where the patient is immobile.

A state of complete or almost complete loss of movement.

A decrease in the ability to move quickly and smoothly

A state of increased muscle tone, resulting in stiffness and resistance to movement.

Involuntary quivering or shaking, especially noticeable when at rest.

Characterized by slow, shuffling steps and a forward-bent posture.

A group of brain disorders characterized by the progressive loss of neurons in specific areas of the brain.

A process of programmed cell death that occurs naturally in the body.

Primary PD, also known as idiopathic PD, is the most common type of Parkinson's disease. It occurs due to the degeneration of more than 80% of dopamine (DA) neurons in the substantia nigra, leading to a significant decrease in DA levels and an increase in acetylcholine (Ach). This imbalance contributes to the symptoms of PD.

Secondary Parkinsonism, or Atypical Parkinsonism, is a group of conditions that mimic the symptoms of PD but arise from different underlying causes. These causes include:

• Vascular Parkinsonism: Due to multiple small strokes affecting brain regions involved in movement control.
• Post-Traumatic Parkinsonism: Resulting from repeated head trauma.
• Toxin-Induced Parkinsonism: Caused by exposure to certain toxins like carbon monoxide, manganese, or pesticides.
• Infectious Parkinsonism: Infection-related damage to brain motor regions.
• Drug-induced Parkinsonism: Induced by certain medications, particularly dopamine blockers like antipsychotics.

Anti-Parkinsonian medications aim to restore the balance between dopamine (DA) and acetylcholine (Ach) in the brain. There are two main types:

1. Dopaminergic drugs: Increase DA levels by various mechanisms.
2. Anticholinergic drugs: Decrease Ach levels, mainly targeting tremors and rigidity.

Levodopa (L-dopa) is a precursor to dopamine. Unlike dopamine itself, L-dopa can cross the blood-brain barrier and is converted into dopamine inside the brain. This helps restore the balance between dopamine (DA) and Acetylcholine (Ach) levels in the brain.

Large doses of Levodopa are required because most of it is broken down into dopamine in the body (gut, blood, liver) before reaching the brain. This causes side effects.

Carbidopa and Benserazide are medications used alongside Levodopa. They inhibit an enzyme called dopa decarboxylase that converts Levodopa to dopamine outside of the brain. This increases the amount of Levodopa that reaches the brain, allowing for a smaller dosage to be used.

The gradual decrease in the effectiveness of levodopa medication over time, leading to the return of Parkinson's symptoms before the next dose is due.

The phenomenon where fluctuations in levodopa's plasma concentration cause periods of normal movement (on) alternating with periods of Parkinson's symptoms (off).

Stimulates α1-receptors on the radial muscle of the eye, causing dilation of the pupils (mydriasis) in high doses; contraindicated in patients with narrow-angle glaucoma.

Levodopa's absorption from the small intestine is reduced by the presence of protein in the diet.

Levodopa is converted to dopamine, a neurotransmitter that is deficient in Parkinson's disease.

Levodopa is transported into the brain via active amino acid transport, competing with other amino acids.

Vitamin B6 enhances the peripheral conversion of levodopa to dopamine, reducing the effectiveness of levodopa in reaching the brain.

Non-selective MAO inhibitors can increase dopamine levels, potentially leading to dangerous interactions with levodopa.

MAOB inhibitors are a type of medication used to treat Parkinson's disease. They work by specifically inhibiting the enzyme MAOB, which breaks down dopamine in the brain. This leads to increased dopamine levels, which helps to alleviate the symptoms of Parkinson's disease.

Rasagiline is a medication used to treat Parkinson's disease. It is a highly potent and selective inhibitor of MAOB, meaning it effectively blocks the enzyme that breaks down dopamine in the brain. It can be used on its own or in combination with other medications.

Amantadine is a medication used to treat Parkinson's disease. It works by increasing dopamine release and decreasing its reuptake in the brain. It is less effective than L-dopa and its effects diminish over time.

Anticholinergic drugs are a type of medication used to treat Parkinson's disease. They work by blocking the action of acetylcholine, a neurotransmitter that contributes to the symptoms of Parkinson's disease.

Benztropine, Trihexyphenidyl, procyclidine, and Biperiden are examples of anticholinergic drugs used to treat Parkinson's disease. They are used as adjunctive therapy, meaning they are used in combination with other medications.

Drugs that inhibit the conversion of levodopa (L-dopa) to dopamine in the periphery, increasing the amount of L-dopa reaching the brain. They help to reduce the side effects associated with peripheral dopamine.

Drugs that block the enzyme Catechol-O-Methyl Transferase (COMT), preventing the breakdown of L-dopa. They help to increase L-dopa's effectiveness and reduce the dosage required.

Involuntary, abnormal movements that develop in patients taking L-dopa therapy for Parkinson's disease. Usually appear after 4-10 years of treatment due to the overstimulation of dopamine receptors in the brain.

Neurological side effects of L-dopa therapy, including delusions, hallucinations, psychosis, mood changes, anxiety, and depression. Resulting from the increased dopamine levels in the brain's mesolimbic and mesocortical pathways.

A common side effect of L-dopa therapy affecting the CTZ (Chemoreceptor trigger zone) in the medulla, causing nausea, vomiting, and loss of appetite.

A medication used to counteract the nausea and vomiting caused by L-dopa. It acts as a D2 receptor blocker but only peripherally, without entering the brain.

Peripheral side effect of L-dopa therapy, causing increased heart rate (tachycardia) and irregular heartbeat (arrhythmia). Also contributes to postural hypotension due to dopamine's vasodilatory properties.

A potent COMT inhibitor used to treat Parkinson's disease. It is effective in managing symptoms and reducing L-dopa dosage but carries a risk of hepatotoxicity (liver damage).

Dopamine receptor agonists stimulate D2 receptors in the striatum, mimicking the effects of dopamine. They are particularly effective in patients who haven't responded well to levodopa, offering advantages like longer duration of action and no dependence on presynaptic conversion to dopamine.

Dopamine receptor agonists are initially considered for patients with mild Parkinson's Disease (PD) and a younger age of onset. They can also be used as adjuncts to levodopa in patients with severe motor fluctuations. Additionally, they can decrease the dose of L-dopa in advanced PD.

Dopamine receptor agonists can cause nausea, vomiting, confusion, psychomotor excitation, and hallucinations. However, they can cause more severe psychiatric complications compared to levodopa alone, as they directly affect the brain's dopamine system.

Bromocriptine, an ergotamine derivative, is a dopamine receptor agonist that can worsen peripheral vascular disease due to its vasoconstrictive properties. It can also cause serious cardiac problems in patients with a history of myocardial infarction.

Apomorphine, a non-ergot dopamine receptor agonist, is used as an injection primarily during 'off' periods of L-dopa treatment, helping to reduce the 'frozen' sensation and improve movement. Due to its high risk of nausea, it's usually preceded by an antiemetic.

Pramipexole and ropinirole are taken orally, while rotigotine is a transdermal patch that can be applied once daily. These non-ergot dopamine receptor agonists are alternatives to bromocriptine with a lower risk of vascular and cardiovascular complications.

Deprenyl (Selegiline) is an irreversible MAOB inhibitor, specifically targeting MAOB (monoamine oxidase type B) in the brain. It increases dopamine levels by inhibiting its breakdown, and also acts as a free radical scavenger protecting brain cells.

Deprenyl can be used as a single drug in early or mild PD or in combination with L-dopa. It can also help improve motor function in patients experiencing 'wearing off' and 'on-off' phenomena associated with levodopa.