Treatment Options for Settling Symptoms in Parkinson's Disease
Levodopa/carbidopa is the most effective medication for treating motor symptoms in Parkinson's disease and should be the first-line treatment for most patients. 1, 2, 3
First-Line Pharmacological Treatment
- Levodopa is the metabolic precursor of dopamine that crosses the blood-brain barrier and is converted to dopamine in the brain, which is the mechanism whereby it relieves symptoms of Parkinson's disease 4
- For optimal absorption, levodopa should be taken at least 30 minutes before meals to avoid interactions with dietary proteins that can reduce efficacy 1, 2
- Carbidopa inhibits decarboxylation of peripheral levodopa, making more levodopa available for transport to the brain and reducing side effects like nausea and vomiting 4
Optimizing Levodopa Administration
- For patients experiencing motor fluctuations on levodopa, implementing a protein redistribution diet (low-protein breakfast and lunch, with normal protein intake at dinner) can improve motor function 1, 2
- Monitor for common side effects of levodopa including nausea, vomiting, abdominal pain, dyspepsia, constipation, weight decrease, dry mouth, and anorexia 2, 4
- Levodopa may cause hyperhomocysteinemia, especially in older patients and those with long-standing disease, requiring vitamin B supplementation 2
Advanced Therapies for Medication-Resistant Symptoms
- Both subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) are effective for motor symptom control when medications are no longer providing adequate relief 1, 2
- If medication reduction is a primary goal, STN DBS is preferred 1
- If there are concerns about cognitive decline or depression, GPi DBS may be more appropriate 1, 3
- Magnetic resonance-guided focused ultrasound (MRgFUS) is an emerging incisionless option for medication-resistant tremor 1
- For continuous dopamine delivery, duodenal infusion of levodopa/carbidopa can be considered for advanced disease with motor fluctuations 5, 6
Management of Sleep Disturbances
- For REM sleep behavior disorder (RBD) in Parkinson's disease:
- Melatonin (starting at 3 mg and increasing by 3-mg increments to 15 mg) is recommended, especially for older patients, as it is only mildly sedating 2, 3
- Clonazepam is commonly used but has side effects including morning sedation, gait imbalance/falls, depression, and cognitive disturbances 2, 3
- Rivastigmine may be appropriate for patients with RBD and cognitive impairment refractory to other treatments 2
Nutritional Management
- Regular monitoring of nutritional and vitamin status is recommended, with particular attention to changes in body weight and the need for vitamin D, folic acid, and vitamin B12 supplementation 2
- Patients with constipation may benefit from fermented milk with probiotics and prebiotic fiber, in addition to increased water and fiber intake 2
- For tube-fed patients on oral levodopa, interrupting enteral nutrition for at least 1 hour before and 30-40 minutes after medication administration is recommended 2
Common Pitfalls and Caveats
- Avoid strict low-protein diets as they may lead to nutritional deficiencies without evidence-based benefits 1, 2, 3
- Increasing doses of levodopa over time are associated with a higher risk for malnutrition, requiring careful monitoring 1, 2, 3
- Patients taking levodopa or dopamine agonists have reported suddenly falling asleep without prior warning while engaged in activities of daily living, including driving 4
- Motor complications like dyskinesias may occur at lower dosages and sooner with levodopa than with other treatments, requiring careful dose adjustment 4, 7
- Sporadic cases of neuroleptic malignant syndrome have been reported with dose reductions or withdrawal of antiparkinsonian agents, requiring careful observation during dosage changes 4