Healthy Living

Cognitive-Enhancing Medication for Parkinson's Disease

Key Takeaways

  • Parkinson’s disease affects the nerve cells in the brain that provide dopamine.
  • It is a progressive medical condition, which can affect body movements.
  • Exelon (rivastigmine) is the only medication approved by FDA for dementia symptoms in Parkinson’s disease. In some cases, the doctor can also prescribe donepezil or galantamine.

What is Parkinson’s disease?

Parkinson’s disease is known to have an impact on the nerve cells in the brain that produce dopamine. It is a progressive disorder of the central nervous system that can affect body movements. The disease develops gradually, wherein there are hardly noticeable tremors in one hand. Parkinson’s disease is commonly associated with tremors. However, it also comes along with stiffness in the body and slowing down of body movements.

In the early stages of the disease, the face may show little or no expression at all. In some cases, the arms may not swing at all while walking. Speech becomes slurred, which worsens over time. However, medications can slow down the progression of the disease.

The symptoms of Parkinson's disease would range from resting tremors, slurred speech or changes in speech, and muscle rigidity. There is no cure for this medical condition, but there are medications and therapies that are known to provide relief from the symptoms one would experience.

Cognitive Deficit

Over the past few decades, Parkinson’s disease was mostly known as a movement disorder, wherein it was characterized by certain symptoms related to slowness of movement and tremors. However, it was gradually recognized for its non-motor related characteristics, which include cognitive difficulties. 

It is difficult to exactly define cognition since it covers various types of mental skills and activities. As a general term, cognition involves how people understand through thinking and experiencing the world and responding to it. It is composed of thought processes that are part of every human action, which includes forming various concepts, storing data and retrieving it for future use, learning new things, planning of events or activities, learning languages and using it, and abstract thinking.

One of the troubling symptoms of Parkinson's disease is mild cognitive impairment (MCI). In many PD cases, individuals experience signs of distraction or being disorganized. In some cases, they have difficulty planning and carrying out simple everyday tasks. It becomes hard for the individual with PD to focus in situations, which involve concentration or attention. They also come across certain situations, where it becomes difficult to remember any information or find it tough to find the right words while speaking up.

For a few individuals, these experiences tend to become annoying over time, whereas for some, they become a hindrance in their routine activities at work or home. Aging individuals are affected by cognitive impairment to some degree. As people age, the brain also changes leading to symptoms of deterioration, which are related to motor skills, critical thinking, and memory pattern. To top it all, stress, depression, and the use of medications can also worsen the matter for certain people.

Hence, it is essential for individuals to inform their doctor if they experience such changes. The doctor can conduct certain tests to come up with a diagnosis. Medications may be started for certain individuals or they may be referred to a neurologist for further assessment. It is also important to note that cognitive deficit and dementia are two different disorders.

Symptoms of Cognitive Changes

Individuals who suffer from Parkinson’s disease may experience mild cognitive impairment (MCI), while a few others may face dementia. The symptoms of mild cognitive impairment are usually moderate and do not interfere with the individual’s ability to function at work and home. In some cases, the symptoms are not easily noticeable, but can only be detected with the help of some tests or diagnosis. Studies have suggested that cognitive changes in individuals would not develop unless they have reached the mid or late stages of the disease. However, it has now been confirmed that mild changes can be seen at the early stages of the disease.

Seeking Help

Cognitive impairment is a highly sensitive issue. For this reason, most affected individuals are usually hesitant to discuss their condition with anyone. The doctor would also be hesitant to discuss the subject with the patient out of concern for the patient who is already under a lot of stress and shock from the PD diagnosis. Thus, it is important for people with PD to initially and gradually open up about their cognitive problems to their doctor. The individual should not ignore these problems thinking that they are only mild and would eventually go away. The doctor can refer PD patients to a psychiatrist, speech consultant, or neuropsychologist for further evaluation and assistance on the problem. Such evaluations are proven to be valuable, especially if they are detected in the early stages of the disease.

Treatment

When an individual reports symptoms related to mild cognitive impairment, the first thing the doctor would do is to rule out other medical conditions apart from Parkinson’s disease such as a deficiency of vitamin B12, fatigue, sleep deprivation, and depression. Note that Parkinson's disease cannot cause immediate changes in a person's mental functioning. If a person experiences sudden cognitive changes, then it can be linked to other conditions or can be a side effect of certain medications. There are drugs available for cognitive impairment. Such drugs were developed for Alzheimer’s disease, but they were found to be useful for Parkinson’s disease as well.

Common Drugs for Parkinson’s Disease

Exelon (rivastigmine) is the only medication approved by FDA for dementia symptoms in Parkinson’s disease. In some cases, the doctor can also prescribe donepezil or galantamine.

Rivastigmine

Rivastigmine is known to treat mild to moderate levels of dementia wherein the patient suffers from memory problems or difficulty in judgment, mild changes in personality, and abstract thinking. These symptoms are especially seen in patients who have medical conditions such as Alzheimer's or Parkinson’s disease.

Rivastigmine is a cholinesterase inhibitor and works by increasing the level of acetylcholine in the brain. This would lead to a reduction in the symptoms of cognitive impairment. Rivastigmine should not be used if you are allergic to the medicine or any content present in the medicine, and allergic to carbamate derivatives such as meprobamate.

Drug interactions can also happen when rivastigmine is combined with other drugs, especially those that have bradycardic effects such as beta-blockers. Beta blockers are drugs used to prevent migraine symptoms, treat anxiety, tremors, hypertension, and irregular heartbeat, among others. The following are common beta-blockers that interact with rivastigmine:

  • Nebivolol
  • Bisoprolol
  • Esmolol
  • Sotalol
  • Betaxolol
  • Metoprolol
  • Nadolol
  • Labetalol
  • Timolol

Before using the medicine, there can be chances that it can lead to certain side effects or interact with certain drugs. Hence, inform your doctor if any of the following applies to you:

  • Pregnant or planning to get pregnant
  • Breastfeeding
  • Taking prescribed or non-prescribed medications
  • History of kidney or liver problems, fast heartbeat, heart-related problems, stroke, respiratory problems such as asthma and COPD, urination problems, epilepsy, pancreatitis, and gastrointestinal problems
  • Dementia not linked to Parkinson's or Alzheimer’s disease
  • Scheduled surgical operation due to another medical condition
  • Dehydrated
  • Weighing less than 50 kg

You also need to inform your doctor if you are taking any of the following medications:

  • Aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs): An example would be ibuprofen since it can lead to an increased risk of stomach bleeding or bowel bleeding.
  • Beta-blockers: These drugs can lead to an increased risk of getting an irregular heartbeat.
  • Anticholinergics: Rivastigmine can decrease the effectiveness of anticholinergic medications such as tolterodine or oxybutynin. 
  • Metoclopramide: The risk of having uncontrolled body movements can also increase when taking this drug.
  • Cholinergic agents: The risk of rivastigmine's side effects would increase with the use of cholinergic agents such as bethanechol.

Rivastigmine improves a person’s ability to think and remember or it would slow down the loss of these abilities. Rivastigmine should be used exactly as prescribed by the doctor. One can also check the label for instructions on the usage of this medicine.

Taking Rivastigmine 

Rivastigmine should be taken orally in the morning and evening after meals unless the doctor prescribes otherwise. It should also be taken on a regular schedule so that the person benefits the most from it. Ensure to take this medicine at the same time each day so there is a fixed schedule of the dosage. The medicine should be continued even if one feels that the symptoms have started to improve. It should be continuously taken so the complete course prescribed by the doctor finishes.

Rivastigmine Side Effects

The following are certain side effects associated with rivastigmine use:

Talk to your doctor if the side effects continue for a longer duration or if they get worse over time. The serious side effects of this medicine include:

  • Severe diarrhea
  • Worsening tremor
  • Bloody or tarry stools
  • Breathing difficulties
  • Swelling of the face, lips, mouth, or tongue
  • Chest pain or tightness
  • Severe allergic reactions
  • Confusion
  • Lack of coordination
  • Painful urination or a decreased urine output
  • Episodes of hallucinations
  • Anxiety attack
  • Depression
  • New tremor symptoms
  • Uncontrollable muscle movements
  • Skin irritation
  • Bloody vomit
  • Trouble in swallowing food or speaking
  • Facial spasms
  • Tongue twitching

Warnings and Precautions

Rivastigmine should only be used by individuals for whom this medicine is prescribed. Thus, it should not be shared with anyone else. Rivastigmine can lead to drowsiness or dizziness, and these effects can worsen if one has consumed alcohol. Do not drive or perform other tasks that would need focus or concentration. Rivastigmine should not be taken more than recommended.

Moreover, do not change the dose or stop taking the medicine without the knowledge of the doctor. Once you start taking rivastigmine, the doctor will gradually increase the dose over several months. This would help decrease the risk of side effects. Hence, one should carefully follow the dosing instructions provided by the doctor. 

Below are the steps to be followed for taking the oral solution of rivastigmine:

  • The oral dosage syringe that came along with the medication should be removed from its protective case.
  • The child-resistant cap should be pushed down and twisted so that the bottle opens up.
  • Place the tip of the oral syringe into the white stopper opening, which is on top of the bottle.
  • While holding the syringe straight up, pull up the plunger on the mark of the syringe according to the recommended dose.
  • Check out for any air bubbles in the liquid present in the syringe. If there are air bubbles, slowly move the plunger up and down a couple of times. Tiny bubbles are nothing to be bothered about but large bubbles should not be there.
  • Ensure that the plunger is placed on the mark of the syringe so that it equals the dose.
  • Pull out the oral syringe from the bottle.
  • Directly swallow the medicine from the syringe itself or one can mix it up with any choice of liquid. You can drink or swallow the solution as a whole.
  • Wipe out the outside of the syringe with a clean cloth or tissue and place it back into the case.
  • Lastly, close the child-resistant cap on the bottle of the medication.