Invega (Paliperidone Palmitate) 30-Day Injection Loading Dose
The recommended loading dose regimen for Invega 30-day injection is 234 mg (150 mg eq. paliperidone) administered into the deltoid muscle on Day 1, followed by 156 mg (100 mg eq. paliperidone) into the deltoid muscle on Day 8. 1, 2
Initial Loading Regimen
- Day 1: 234 mg paliperidone palmitate (150 mg eq. paliperidone) injected into the deltoid muscle 1
- Day 8: 156 mg paliperidone palmitate (100 mg eq. paliperidone) injected into the deltoid muscle 1
- No oral supplementation is required with this loading regimen, as therapeutic blood levels are achieved rapidly 1, 2
Needle Selection for Loading Doses
The needle size for deltoid injections is weight-dependent 1:
Rationale for Deltoid Loading
Deltoid injection is specifically required for the loading doses because it produces approximately 28% higher maximum plasma concentrations compared to gluteal injection 3. This higher bioavailability from deltoid administration allows for rapid achievement of therapeutic concentrations without oral supplementation 1.
Maintenance Dosing After Loading
- Monthly maintenance doses range from 39-234 mg (25-150 mg eq. paliperidone), with 117 mg (75 mg eq. paliperidone) as the recommended dose 1
- Maintenance injections can be administered into either deltoid or gluteal muscle 1, 2
- Monthly doses may be given ±7 days without clinically significant impact on plasma concentrations 1
Pharmacokinetic Profile
The loading regimen is based on population pharmacokinetic modeling demonstrating that 1:
- Drug release begins as early as Day 1 after injection 3
- Maximum plasma concentrations are reached at 13 days 3
- Duration of action extends up to 126 days 3
Critical Safety Considerations
Be aware that paliperidone palmitate has caused severe drug-induced parkinsonism with potentially long-term consequences. In one case report, a patient developed severe parkinsonism and died approximately 5 months after receiving the loading doses (234 mg followed by 156 mg) 4. While confounding factors existed, the temporal relationship suggests paliperidone LAI was a contributing factor 4.
Dosing Flexibility
The Day 8 dose may be administered ±2 days without clinically significant impact on plasma concentrations 1. This provides some scheduling flexibility while maintaining therapeutic efficacy.