Parkinson’s disease is predominant in the elderly. It is a neurological disorder in which dopamine is diminished in the nigostratial area of the brain, resulting in an imbalance between dopamine and acetylcholine. Therefore the symptoms are reflective of an abundance in acetylcholine.
Increased acetylcholine leads to symptoms of resting tremor, postural instability, bradykinesia (slow movement), and muscle rigidity. Secondary symptoms include decreased dexterity, facial flattening, and small slanted written words. Disease progression is monitored by Hoehn and Yahr scale. Stage I is defined as only same side mild symptoms. Stage II is defined as small movement impairment with both side functioning affected. Stage III is significantly moderate to severe slowed movement. Stage IV is defined as extremely limited movement. Stage V is defined as needing 24 hour supervision.
Etiology or cause is unknown. Associations between the development and certain factors such as oxidative stress, chronic infections, and inflammation exist. Presentation depicts demographics of > 65-80 years of age with men of any ethnicity being twice as likely as women of any ethnicity to be inflicted. Treatment focuses on preserving function and mobility, minimizing side effects and complications, as well as managing secondary symptoms of fatigue, depression, and mental decline.
The therapy used to treat Parkinson’s varies based on the individual’s presenting symptoms as well as age. These therapies range from carbidopa/levodopa, direct dopamine agonists, anti-cholinergic agents, NMDA antagonists, MAO-B inhibitors, and COMT agents.
Anti-cholinergic agents are often initial therapy depending on the symptom depiction and patient age. Anti-cholinergic agents include diphenhydramine or Benadyl. Their role in therapy is to treat the tremors in young patients or are useful for mild disabilities in first few years of onset. The disadvantages are the side effects. Diphenhydramine can lead to dry mouth, urinary difficulty, dry eyes, confusion, drowsiness, and potentiate fall risks. Thus, as a result there use is reserved to prior discussed optimal patient population.
Dopamine agonists are extremely beneficial therapeutic agents. These medications work to increase the deficient dopamine and replenish the balance between dopamine and acetylcholine. Some of the common medications include Mirapex (pramixezole), Requip (ropinerole), and bromocriptine. Side effects include agitation, hallucinations, hand and feet swelling, low blood pressure, sleep attacks, and impulse control. Using these medications with other Parkinson’s treatment requires monitoring and dosage adjustment, however, these medications are beneficial across all stages in symptomatic treatment.
Carbidopa/levodopa is the cornerstone of therapy. This medication is the only therapy shown to aid in progression decline. Carbidopa is a chemical unable to cross the blood brain barrier inhibiting levodopa conversion to dopamine until in the brain, where it is necessary. Various formulations exist as either controlled release or immediate release with dosages as 25-50 mg of carbidopa and 100-200 mg of levodopa. It is best to take medication 30-60 minutes after meals. Common side effects include motor abnormalities and in the rarest case neuromalignant syndrome.
Rare or uncommon medications used to treat Parkinson’s include MAO-B inhibitors and COMT inhibitors. MAO-B inhibitors selectively target monoamine oxidase B, resulting in increased dopamine and reducing side effects. These medications include Azilect and Eldpyl. COMT are catechol-o-methyl transferase inhibitors, increasing levodopa and thus dopamine. COMT medications need to be used in combination with levodopa and never in combination with MAO-B. COMT medications may result in anorexia, discolored urine, sleep disorders, hyperactivity, and/or liver toxicity. Both of these classes of medications are reserved for difficult to manage patients unresponsive to standards of care.
Even those patients responsive to standards of care may exhibit manageable symptoms suggesting inadequate medication. These include on off, wearing off, freezing, and levodopa induced abnormal movements. On off syndrome is described as sporadic medication effectiveness. Wearing off is the decline in medication effectiveness prior to next dose. Freezing is defined as inability to move or loss of muscle function in a short amount of time. Levodopa induced abnormal movements are either inner restlessness or involuntary movements. These adversities can be managed, including long acting carbidopa/levodopa, dopamine agonist use, beta blockers, and anti-cholinergics such as Benadryl.
Parkinson’s is not a disease of just the elderly. It leaves the young and old with a less than optimal life. Therefore understanding the disease and available treatments can assist in reducing this decreased quality of life. Become informed.
Kimberly Hoff, Pharm D, BCPS, BCACP, CDE