Treatment for Parkinsonism with Tremors
Levodopa/carbidopa is the most effective first-line treatment for parkinsonism with tremors and should be initiated when symptoms interfere with function or quality of life. 1, 2, 3
First-Line Pharmacological Treatments
- Levodopa/carbidopa is the most effective medication for treating parkinsonian motor symptoms, including tremors, and should be the first choice for most patients 1, 2, 4
- For optimal absorption, levodopa should be taken at least 30 minutes before meals to avoid interactions with dietary proteins that reduce its efficacy 1, 2
- The initial dose should be low with gradual increases to minimize side effects, especially in patients over 60 years of age 5, 3
- Anticholinergics such as trihexyphenidyl may be particularly effective for tremor control, with an initial dose of 1 mg daily, gradually increasing to a total daily dosage of 6-10 mg (some patients may require 12-15 mg) 5, 6
Optimizing Medication Administration
- Implementing a protein redistribution diet (low-protein breakfast and lunch, with normal protein intake at dinner) can improve motor function and increase "ON" time in patients experiencing motor fluctuations 1, 2
- The total daily intake of medications like trihexyphenidyl is best tolerated if divided into 3 doses and taken at mealtimes 5
- For patients on high doses of trihexyphenidyl (>10 mg daily), dividing into 4 parts with 3 doses at mealtimes and the fourth at bedtime may improve tolerability 5
- Avoid abrupt withdrawal of antiparkinsonian medications as this may result in acute exacerbation of symptoms or neuroleptic malignant syndrome 5
Second-Line and Adjunctive Treatments
- For patients with insufficient tremor response to levodopa, consider adding propranolol which may improve both resting and action tremor 4
- Clozapine may be considered as an adjunct therapy for tremor control despite its adverse effect profile 4
- In cases of drug-induced parkinsonism, consider switching to antipsychotics with lower risk such as quetiapine or clozapine 7
- For REM sleep behavior disorder associated with parkinsonism, melatonin (starting at 3 mg and increasing by 3-mg increments to 15 mg) is recommended, especially for older patients 1, 2
Managing Motor Complications
- For patients developing motor fluctuations, strategies include:
- Deep brain stimulation (DBS) of either subthalamic nucleus (STN) or globus pallidus internus (GPi) should be considered for advanced Parkinson's disease with motor fluctuations refractory to medication 1, 4
- For patients with cognitive concerns, GPi rather than STN deep brain stimulation is preferred if surgical intervention becomes necessary 1, 2
Monitoring and Side Effect Management
- Monitor for common side effects of levodopa including nausea, vomiting, abdominal pain, dyspepsia, constipation, weight decrease, dry mouth, and anorexia 1, 2
- Levodopa may cause hyperhomocysteinemia, especially in older patients and those with long-standing disease, requiring vitamin B supplementation 1, 2
- Regular assessment using standardized scales like the Abnormal Involuntary Movement Scale (AIMS) is recommended every 3-6 months, particularly for patients on antipsychotics 7
- Regular monitoring of nutritional and vitamin status is essential, with particular attention to changes in body weight and the need for vitamin D, folic acid, and vitamin B12 supplementation 1
Special Considerations
- For patients with troublesome dyskinesias, reducing levodopa doses may be beneficial 1
- Avoid strict low-protein diets as they are not supported by evidence and may lead to nutritional deficiencies 1, 2
- For tube-fed patients on oral levodopa, interrupt enteral nutrition for at least 1 hour before and 30-40 minutes after medication administration 1, 2
- Increasing doses of levodopa over time are associated with a higher risk for malnutrition, requiring careful monitoring 1, 2