Paliperidone Palmitate Dosing Regimen for Schizophrenia
The recommended dosing regimen for paliperidone palmitate (Invega) for schizophrenia treatment is an initiation dose of 234 mg on day 1 followed by 156 mg on day 8 (both administered in the deltoid muscle), then monthly maintenance doses of 39-234 mg (with 117 mg being the recommended maintenance dose) administered in either the deltoid or gluteal muscle. 1, 2
Initiation Dosing
- Day 1: 234 mg (150 mg eq. paliperidone) administered in the deltoid muscle
- Day 8: 156 mg (100 mg eq. paliperidone) administered in the deltoid muscle
- Needle selection:
- For patients <90 kg: 1-inch 23-gauge needle
- For patients ≥90 kg: 1.5-inch 22-gauge needle
No oral antipsychotic supplementation is required during initiation 1, 2.
Maintenance Dosing
- Monthly maintenance dose range: 39-234 mg (25-150 mg eq.)
- Recommended maintenance dose: 117 mg (75 mg eq.)
- Administration site: Either deltoid or gluteal muscle
- Deltoid: Use weight-adjusted needle as described above
- Gluteal: Use 1.5-inch 22-gauge needle regardless of weight
The first maintenance dose should be administered one month after the day 8 injection 1, 3.
Dosing Flexibility
- The day 8 dose may be administered ±2 days of the scheduled date
- Monthly maintenance doses may be administered ±7 days of the scheduled date
- These timing variations do not significantly impact plasma concentrations 1, 2
Special Populations
Renal Impairment
- Mild impairment (CrCl 50-80 mL/min): Dosage adjustment required
- Moderate to severe impairment: Not recommended
Hepatic Impairment
- Mild to moderate impairment: No dose adjustment required
- Severe impairment: Insufficient data available
Elderly Patients
- With normal renal function: Same dosage as younger adults
- With age-related decline in renal function: Adjust dosage accordingly 1, 2
Clinical Efficacy
Paliperidone palmitate has demonstrated efficacy in both acute and maintenance treatment of schizophrenia. Significant improvement in PANSS total scores can be observed as early as day 8 after the initial injection and continues to improve with subsequent dosing 4, 5.
In clinical trials, approximately 78.4% of patients showed a response (defined as ≥30% reduction in PANSS total score) by the end of treatment 5.
Common Side Effects
- Muscle rigidity (11.8%)
- Akathisia (11.1%)
- Injection site pain (7.6%)
- Weight gain (7.6%)
- Insomnia (7.6%)
- Anxiety (3.1-3.9%)
- Dizziness (2.5%)
- Headache (4.0%) 4, 5
Switching from Other Antipsychotics
- From oral antipsychotics: Paliperidone palmitate can be initiated the day after discontinuing previous oral treatment
- From other long-acting injectables: Initiate paliperidone palmitate at the time of the next scheduled injection of the previous LAI 1, 2
Missed Doses Management
If more than 6 weeks have passed since the last maintenance dose, re-initiation should follow the original loading dose schedule (234 mg on day 1,156 mg on day 8) 1, 2.
Clinical Considerations
- No oral supplementation is required during initiation, which is an advantage over some other long-acting injectables
- The rapid achievement of therapeutic levels (by day 8) allows for quicker clinical response
- Monthly dosing may improve adherence compared to more frequent administration schedules
- Monitor for common side effects, particularly extrapyramidal symptoms and weight gain
Paliperidone palmitate offers a convenient once-monthly dosing regimen with a straightforward initiation protocol that does not require oral supplementation, potentially improving treatment adherence in patients with schizophrenia.