Can clozapine (atypical antipsychotic) be used to reduce hemiballismus in a patient who has failed other treatments?

Clozapine for Hemiballismus

Clozapine can be effective for treating hemiballismus, particularly in patients who have failed standard dopamine receptor blockers like haloperidol, with clinical improvement typically observed within days at low doses (50 mg/day). 1

Evidence for Clozapine in Hemiballismus

The use of clozapine for hemiballismus is supported by case reports demonstrating rapid clinical response when traditional neuroleptics fail. In two documented cases, patients with hemiballismus who were nonresponsive to haloperidol for one month showed amelioration of ballistic movements within just a few days after starting clozapine at 50 mg/day. 1 This suggests clozapine may offer a valuable alternative mechanism of action beyond simple dopamine D2 blockade. 1

Treatment Algorithm for Hemiballismus

First-Line Approach

• Start with standard dopamine receptor blockers (haloperidol or perphenazine) at low doses, titrating as tolerated until movements are controlled. 2
• These agents have an established track record for suppressing choreic and ballistic movements. 2

Second-Line: Atypical Antipsychotics

• If standard neuroleptics fail or are poorly tolerated, consider atypical antipsychotics including clozapine, risperidone, or olanzapine, which may have reduced risk of extrapyramidal side effects. 2
• Olanzapine has demonstrated quantifiable reduction in hemiballistic movements, with one case showing upper extremity movements decreasing from 23.5 to 3.0 per 30-minute session during reaching tasks. 3
• Clozapine at 50 mg/day is the specific dose documented to be effective, with response typically within days rather than weeks. 1

Address Underlying Etiology

• In elderly patients with uncontrolled diabetes, aggressive glucose control is essential, as nonketotic hyperglycemia is an important reversible cause. 2, 4
• Spontaneous improvement or remission occurs in many patients once the underlying cause is treated. 4
• In vascular cases, the ballistic movements tend to subside over time, allowing drug withdrawal in many cases. 2

Clozapine-Specific Considerations

Monitoring Requirements

• Mandatory weekly white blood cell counts for the first 6 months, then every 2 weeks thereafter due to agranulocytosis risk. 5
• Monitor for dose-dependent seizure risk, particularly with rapid dose escalation. 5
• Watch for sedation, hypersalivation, tachycardia, orthostatic hypotension, and weight gain. 5, 6

Advantages Over Traditional Neuroleptics

• Clozapine causes minimal extrapyramidal side effects compared to haloperidol. 6
• Its complex mechanism involving multiple neurotransmitter systems, including serotonergic antagonism, may explain efficacy when dopamine blockers alone fail. 5

Critical Pitfalls to Avoid

• Do not dismiss hemiballismus in diabetic patients as purely neurological—check glucose levels and HbA1c, as hyperglycemia may be the sole reversible cause. 4
• Do not escalate clozapine doses rapidly—the effective dose for hemiballismus (50 mg/day) is far lower than doses used for schizophrenia (200-300+ mg/day), minimizing seizure risk. 1, 7
• Do not continue ineffective therapy for extended periods—if haloperidol shows no response after 2-4 weeks, switch to an atypical antipsychotic rather than continuing for months. 1
• Do not overlook the need for supportive care—severe hemiballismus can cause exhaustion, injury, and metabolic complications requiring good supportive management. 2