Invega Trinza 546 mg Every 3 Months
For a patient stable on Invega Sustenna 156 mg monthly, the equivalent Invega Trinza dose is 546 mg administered every 3 months 1.
Conversion Dosing
The conversion from Invega Sustenna (monthly) to Invega Trinza (3-monthly) follows a 3.5-fold multiplication of the last monthly dose 1, 2:
- Invega Sustenna 156 mg monthly → Invega Trinza 546 mg every 3 months
This is the FDA-approved conversion based on pharmacokinetic modeling that ensures therapeutic paliperidone levels are maintained throughout the 3-month dosing interval 1, 2.
Prerequisites for Conversion
Before switching to Invega Trinza, the patient must meet these criteria 1:
- Minimum 4 months of adequate treatment with Invega Sustenna
- Last two doses of Invega Sustenna should be the same strength (both 156 mg in this case) to establish consistent maintenance dosing
- Patient must be clinically stable on the monthly regimen
Timing of First Trinza Injection
Administer the first Invega Trinza 546 mg dose when the next monthly Invega Sustenna injection would be due 1. A dosing window of ±7 days from the scheduled monthly time point is acceptable without compromising plasma concentrations 2.
Administration Details
Injection site options 1:
- Deltoid muscle: Use 1-inch 22-gauge thin wall needle if patient weighs <90 kg; use 1.5-inch 22-gauge thin wall needle if ≥90 kg
- Gluteal muscle: Use 1.5-inch 22-gauge thin wall needle regardless of weight
Critical administration steps 1:
- Shake syringe vigorously for at least 15 seconds immediately before injection
- Inject within 5 minutes of shaking to ensure homogeneous suspension
- Use only the thin wall needles provided with Trinza (do NOT use needles from Sustenna packs)
Subsequent Maintenance Dosing
After the initial 546 mg dose, continue with 546 mg every 3 months 1. The maintenance dosing window allows ±2 weeks flexibility around the 3-month time point 2.
Dose Adjustments
If dose adjustment is needed based on tolerability or efficacy, changes can be made every 3 months within the range of 273-819 mg 1. However, due to the long-acting nature, response to dose changes may not be apparent for several months 1.
Special Populations
Mild renal impairment (CrCl 50-80 mL/min): First adjust and stabilize on Invega Sustenna at reduced dose, then convert to corresponding Trinza dose using the 3.5-fold multiplication 1.
Moderate to severe renal impairment (CrCl <50 mL/min): Invega Trinza is not recommended 1.
Clinical Advantages
The 3-month formulation provides superior relapse prevention compared to oral paliperidone, with 50% of patients remaining relapse-free for approximately 13 months after withdrawal from PP3M versus only 2 months for oral formulations 3. The extended dosing interval improves adherence while maintaining equivalent safety and efficacy to monthly injections 2, 3.