Can You Stop Haloperidol and Give Invega Sustenna 234mg on the Same Day?
Yes, you can stop haloperidol and initiate paliperidone palmitate (Invega Sustenna) 234 mg on the same day without oral supplementation or bridging. The recommended loading dose strategy for Invega Sustenna is specifically designed to achieve therapeutic plasma concentrations rapidly without requiring concurrent oral antipsychotic coverage. 1, 2
Evidence-Based Rationale for Same-Day Transition
Pharmacokinetic Profile Supports Immediate Switch
Paliperidone palmitate 234 mg (150 mg eq) on Day 1 achieves therapeutic blood levels rapidly without oral supplementation, eliminating the need for haloperidol bridging. 1
The biphasic pharmacokinetic profile includes an initial fast zero-order input phase that allows rapid attainment of therapeutic concentrations, followed by sustained first-order input for monthly maintenance. 3
No oral antipsychotic bridging is required when initiating paliperidone palmitate with the standard loading dose regimen. 1
Recommended Initiation Protocol
Standard Loading Dose Regimen
Day 1: Administer 234 mg (150 mg eq) deltoid injection to achieve rapid therapeutic levels. 1, 2
Day 8: Administer 156 mg (100 mg eq) deltoid injection to maintain therapeutic concentrations. 1, 2
Day 36 and monthly thereafter: Administer 39–234 mg (based on efficacy and tolerability) in either deltoid or gluteal muscle. 2
Administration Considerations
Both loading doses (Day 1 and Day 8) must be administered in the deltoid muscle to optimize absorption kinetics. 1
Maintenance doses can be given in either deltoid or gluteal sites. 1
No refrigeration or reconstitution is required prior to administration. 1
Critical Safety Considerations Before Initiating
Pre-Treatment Assessment Required
Before following the standard loading dose protocol, you must assess the patient's current haloperidol dose and antipsychotic sensitivity. 4
Patients on high-dose haloperidol (>5 mg/day) or with history of extrapyramidal symptoms may develop severe and prolonged Parkinsonism with the standard 234 mg loading dose. 4
The loading dose strategy can result in transient plasma concentration excursions above therapeutic levels, increasing risk of tachycardia, hypotension, QT prolongation, and extrapyramidal symptoms. 3
Modified Approach for High-Risk Patients
For patients on haloperidol >5 mg/day or with prior EPS, consider starting with a lower dose (156 mg on Day 1,117 mg on Day 8) rather than the standard loading regimen. 4
Baseline assessment must include ECG monitoring for QTc interval, as both haloperidol and paliperidone can prolong QT. 5
Document baseline extrapyramidal symptoms, weight, and metabolic parameters before initiating. 6
Monitoring Requirements Post-Transition
First 4 Weeks
Assess treatment response at 4 weeks minimum with documented adherence before concluding efficacy. 6
Monitor for extrapyramidal symptoms (tremor, rigidity, bradykinesia, akathisia) at each visit, as paliperidone can cause these effects. 3, 4
If severe EPS develops, therapeutic drug monitoring using serum prolactin levels can help assess drug exposure when direct plasma paliperidone measurement is unavailable. 4
Ongoing Surveillance
Monitor for weight gain, metabolic changes (fasting glucose, lipids), and prolactin elevation, which are common with paliperidone. 2
If significant positive symptoms persist after 4 weeks at therapeutic dose with confirmed adherence, consider switching to an alternative antipsychotic with different pharmacodynamic profile. 6
Common Pitfalls to Avoid
Do not bridge with oral haloperidol after initiating paliperidone palmitate unless the patient was on very high doses (≥10 mg/day haloperidol equivalent) and you are using a modified lower loading dose. 7, 1
Do not assume the standard 234 mg loading dose is appropriate for all patients—assess prior antipsychotic exposure and EPS history first. 4
Do not administer the Day 8 dose in the gluteal muscle—both loading doses require deltoid administration for optimal pharmacokinetics. 1
Do not conclude treatment failure before 4 weeks at therapeutic dose—paliperidone requires adequate time to assess efficacy. 6
Special Populations
Patients Previously on Risperidone ≥4 mg/day
Bridging with oral risperidone for ≥7 days after the first paliperidone injection is associated with reduced hospitalization days in patients transitioning from risperidone ≥4 mg/day. 7
This bridging strategy may be considered for patients on higher risperidone doses, though the package insert does not recommend it. 7