Discussion Topic: A Patient Who Has Parkinson's Disease

Discussion Topic A Patient Who Has Parkinsons Disease Takes Levodopa

Patients diagnosed with Parkinson's disease (PD) often rely on pharmacological interventions to manage their motor symptoms effectively. Levodopa, combined with carbidopa, remains the cornerstone of PD treatment due to its efficacy in alleviating symptoms such as bradykinesia, rigidity, and tremors (Srinivasan et al., 2020). However, managing medication-related complications and optimizing therapeutic outcomes require careful consideration, especially when patients experience troublesome motor fluctuations like tremors or freezing episodes between doses. This essay discusses appropriate clinical responses to such issues and identifies suitable initial therapy options considering patient comorbidities.

Managing Tremors Between Doses of Levodopa and Carbidopa

One common complication experienced by PD patients on levodopa and carbidopa therapy is the appearance of tremors occurring between doses, often indicating "wearing-off" phenomena (Sharma & Mahajan, 2021). The primary care nurse practitioner (NP) faced with this scenario should consider adjusting the medication regimen to improve symptom control. Option a, adding amantadine, is a viable intervention; amantadine has been shown to reduce tremors and dyskinesias by functioning as an NMDA receptor antagonist (Rao & Barkley, 2019). Conversely, increasing the levodopa dose (option b) might exacerbate fluctuations and dyskinesias if not carefully titrated, and discontinuing carbidopa (option c) is inappropriate as it enhances central nervous system availability of levodopa. Option d, adding entacapone, a catechol-O-methyltransferase (COMT) inhibitor, prolongs levodopa action but doesn't directly address tremor frequency fluctuations and may cause side effects like diarrhea or hepatotoxicity (Raju & De Silva, 2020). Therefore, the addition of amantadine is a targeted strategy to reduce tremor episodes between doses.

Addressing Freezing Episodes Between Doses

Freezing of gait is a disabling motor symptom where patients temporarily feel as if their feet are glued to the ground. When patients on levodopa and carbidopa report these episodes, the goal is to implement medications that may mitigate such motor fluctuations without exacerbating side effects or contraindications. Option a, selegiline, is a monoamine oxidase B (MAO-B) inhibitor which can provide symptomatic relief but might not significantly influence freezing episodes (Schapira & Olanow, 2022). Option b, apomorphine, is a potent dopamine agonist administered subcutaneously for rapid alleviation of sudden off episodes, including freezing (Meschia et al., 2019). However, it is generally reserved for advanced PD and requires careful administration due to potential hypotension and nausea. Option c, modified-release levodopa, offers extended plasma levels and could smooth transitions between doses, potentially reducing freezing episodes. Yet, evidence for efficacy specifically on freezing is limited. Option d, amantadine, may help with tremors but is less effective for freezing (Bogdanov et al., 2021). Given the need for rapid relief in freezing episodes, apomorphine is often considered the most appropriate choice for managing sudden "off" episodes in clinical practice.

Initial Pharmacotherapy in a Patient with Parkinson's Disease and Comorbidities

When initiating PD treatment in a 65-year-old with comorbidities such as emphysema and narrow-angle glaucoma, selecting an appropriate medication requires careful assessment to avoid adverse effects. Ropinirole hydrochloride, a dopamine agonist, (option a) is effective but has been associated with adverse effects such as hypotension and impulse control disorders. Selegiline (option b), an MAO-B inhibitor, offers symptomatic relief with minimal impact on respiratory or ocular conditions. Carbidopa/levodopa (option c) remains the most efficacious initial therapy for advanced PD symptoms, but in patients with narrow-angle glaucoma, caution is warranted as traditional levodopa does not contraindicate glaucoma but can cause peripheral hypotension, which may exacerbate ocular issues. Benztropine (option d), an anticholinergic, is generally avoided in elderly patients, especially those with respiratory and ocular comorbidities, due to cognitive impairment and anticholinergic side effects. Therefore, considering the patient's age and existing comorbidities, initiating therapy with selegiline provides symptom management while minimizing risks—especially as it does not impact pulmonary function adversely and has a safety profile in glaucoma (Schapira & Olanow, 2022).

Conclusion

Management of Parkinson's disease requires personalized approaches to optimize motor function and minimize side effects. When faced with fluctuations such as tremors between doses or freezing episodes, medications like amantadine and apomorphine provide targeted benefits. In patients with complex medical histories, selecting drugs with favorable safety profiles, such as selegiline, is critical to avoid exacerbating comorbidities. Ultimately, integrating clinical evidence, patient-specific factors, and ongoing monitoring underpins effective Parkinson's disease management.

References

• Bogdanov, M. B., Sharma, R., & Sharma, S. (2021). Pharmacological management of freezing of gait in Parkinson's disease. Movement Disorders, 36(3), 561–568.
• Rao, S., & Barkley, M. (2019). Amantadine in Parkinson's disease: A review of its use and mechanism. Current Neuropharmacology, 17(6), 583–590.
• Raju, K., & De Silva, T. (2020). COMT inhibitors in Parkinson's disease: Pharmacology and clinical considerations. Drug Design, Development and Therapy, 14, 413–427.
• Schapira, A. H., & Olanow, C. W. (2022). Therapies for Parkinson's disease: Updated considerations. The Lancet Neurology, 21(2), 105–117.
• Srinivasan, R., et al. (2020). Levodopa therapy in Parkinson's disease: Clinical efficacy and limitations. Neurology and Therapy, 9(4), 623–635.
• Sharma, S., & Mahajan, V. (2021). Motor fluctuations in Parkinson's disease: Pathophysiology and management. Canadian Journal of Neurological Sciences, 48(2), 170–179.
• Meschia, J. F., et al. (2019). Use of apomorphine for off episodes in Parkinson's disease. Current Treatment Options in Neurology, 21(10), 44.
• Rao, S., & Barkley, M. (2019). Amantadine in Parkinson's disease: A review of its use and mechanism. Current Neuropharmacology, 17(6), 583–590.
• Sharma, S., & Mahajan, V. (2021). Motor fluctuations in Parkinson's disease: Pathophysiology and management. Canadian Journal of Neurological Sciences, 48(2), 170–179.
• Meschia, J. F., et al. (2019). Use of apomorphine for off episodes in Parkinson's disease. Current Treatment Options in Neurology, 21(10), 44.