What is the best course of action for an 80-year-old female with Parkinson's disease, recently switched from risperidone and an antihistamine to levodopa and carbidopa, and started on quetiapine, who is experiencing mental status changes and abdominal symptoms?

Management of Mental Status Changes and Abdominal Symptoms in an Elderly Parkinson's Patient

The patient's mental status changes and abdominal fluttering are likely adverse effects from the medication changes, particularly the addition of quetiapine (Seroquel) and levodopa/carbidopa, and require immediate discontinuation of quetiapine while adjusting the levodopa/carbidopa dosage.

Assessment of Current Symptoms

The patient's presentation suggests two distinct but potentially related issues:

1. Mental status changes: Likely related to:

   • Recent medication changes (risperidone discontinuation and addition of quetiapine)
   • Potential drug interactions between levodopa/carbidopa and quetiapine
   • Possible neuroleptic malignant syndrome (NMS) or central anticholinergic toxicity

2. Abdominal fluttering: Potentially caused by:

   • Gastrointestinal side effects of levodopa/carbidopa 1, 2
   • Autonomic effects of quetiapine 3

Immediate Management Steps

1. Discontinue quetiapine (Seroquel):

   • Quetiapine can cause significant mental status changes in elderly patients 3
   • The combination of recent medication changes increases risk of adverse effects
   • Abrupt discontinuation is appropriate given the acute mental status changes

2. Evaluate for neuroleptic malignant syndrome (NMS):

   • Check for fever, muscle rigidity, altered consciousness, autonomic dysfunction
   • Order CPK, CBC, renal function, and myoglobin levels 1, 2
   • This is especially important with recent antipsychotic medication changes

3. Adjust levodopa/carbidopa dosage:

   • Start with a lower dose and titrate gradually 1, 2
   • Monitor for improvement in both mental status and abdominal symptoms
   • Elderly patients require more careful titration to avoid adverse effects

Management of Psychosis in Parkinson's Disease

If psychosis was the reason for the medication changes:

1. First-line approach: Reduce anti-Parkinson medications in this order 4:

   • First: anticholinergics, amantadine, selegiline
   • Second: dopamine agonists
   • Last: levodopa/carbidopa (reduce to lowest effective dose)

2. If antipsychotic treatment is necessary:

   • Pimavanserin is preferred as it has shown lower mortality compared to no treatment in PD psychosis 5
   • Clozapine has proven efficacy but requires blood monitoring 6
   • Low-dose quetiapine can be reconsidered only after stabilization, starting at very low doses (12.5-25mg) 7, 6

Management of Gastrointestinal Symptoms

For the abdominal fluttering sensation:

1. Rule out serious causes:

   • Assess for impaction or obstruction 8
   • Check for hypercalcemia, hypokalemia, and other metabolic causes 8

2. Supportive measures:

   • Increase fluid intake and dietary fiber if appropriate 8
   • Consider prokinetic agent (e.g., metoclopramide) if symptoms persist, but use with caution in Parkinson's 8

Monitoring and Follow-up

1. Short-term monitoring (next 24-48 hours):

   • Daily assessment of mental status
   • Vital signs including orthostatic blood pressure measurements
   • Gastrointestinal symptom evaluation

2. Laboratory monitoring:

   • Renal function and electrolytes
   • Complete blood count
   • Liver function tests

Common Pitfalls to Avoid

1. Do not reintroduce multiple medications simultaneously

   • Make one change at a time to identify which medication causes adverse effects

2. Avoid high-dose antipsychotics in elderly Parkinson's patients

   • Even atypical antipsychotics can worsen motor symptoms 7

3. Do not ignore the potential for drug-induced psychosis

   • Up to 20-30% of PD patients develop psychosis from anti-PD medications 4

4. Avoid rapid dose escalation of any medication

   • Elderly patients with Parkinson's are extremely sensitive to medication changes

This patient's situation represents a common challenge in managing Parkinson's disease in the elderly. The mental status changes and abdominal symptoms strongly suggest medication-related adverse effects that require prompt intervention to prevent more serious complications.