What is the recommended starting regimen for Invega Sustenna (paliperidone palmitate) in an adult patient with schizophrenia?

Starting Protocol for Invega Sustenna (Paliperidone Palmitate)

The recommended initiation regimen for Invega Sustenna 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, with no oral antipsychotic supplementation required. 1, 2

Initial Dosing Schedule

Day 1 Injection

• Administer 234 mg (150 mg eq. paliperidone) into the deltoid muscle 1, 3, 2
• Use a 1-inch 23-gauge needle for patients weighing <90 kg 1, 2
• Use a 1.5-inch 22-gauge needle for patients weighing ≥90 kg 1, 2
• No oral antipsychotic supplementation is necessary with this loading dose strategy 1, 2, 4

Day 8 Injection

• Administer 156 mg (100 mg eq. paliperidone) into the deltoid muscle 1, 2
• Use the same weight-adjusted needle sizing as Day 1 1, 2
• This dose may be administered ±2 days (Days 6-10) without clinically significant impact on plasma concentrations 1, 2

Onset of Efficacy

• Significant symptom improvement occurs by Day 8 after the initial 234 mg deltoid injection, as demonstrated by greater PANSS total score improvement compared to placebo 5, 3
• Continued improvement is observed at Day 22 (p≤0.007) and Day 36 (p<0.001) following the Day 8 injection of 156 mg 5

Maintenance Dosing (Starting Day 36)

• Monthly maintenance doses range from 39-234 mg (25-150 mg eq. paliperidone) 1, 2, 4
• The recommended maintenance dose is 117 mg (75 mg eq. paliperidone) 1, 2
• Maintenance injections can be administered into either deltoid (weight-adjusted needle) or gluteal muscle (1.5-inch 22-gauge needle) 1, 2
• Monthly doses may be administered ±7 days without clinically significant impact on plasma concentrations 1, 2

Switching from Other Antipsychotics

From Oral Antipsychotics

• Initiate paliperidone palmitate the day after discontinuing oral antipsychotic treatment 1, 2
• Follow the standard Day 1/Day 8 deltoid initiation protocol 1, 2

From Other Long-Acting Injectable Antipsychotics

• Initiate paliperidone palmitate at the time of the next scheduled injection of the previous LAI 1, 2
• Continue monthly thereafter 1, 2
• No additional loading doses are required when switching from other LAIs 2

Special Population Dosing Adjustments

Renal Impairment

• Patients with mild renal impairment (CrCL 50-80 mL/min) require dosage adjustment 1, 2
• No dose adjustment needed for normal renal function 2

Hepatic Impairment

• No dose adjustment required for mild or moderate hepatic impairment 1, 2
• No data exist for severe hepatic impairment 1, 2

Elderly Patients

• Elderly patients with normal renal function receive the same dosage as younger adults 1, 2
• Adjust dosage if age-related decline in CrCL is present 1, 2

Baseline and Monitoring Requirements

Before Starting Treatment

• Obtain BMI, waist circumference, blood pressure, HbA1c, glucose, lipids, prolactin, liver function tests, urea and electrolytes, full blood count, and electrocardiogram 6

Early Monitoring (First 6 Weeks)

• Check fasting glucose at 4 weeks following initiation 6
• Monitor BMI, waist circumference, and blood pressure weekly for 6 weeks 6

Ongoing Monitoring

• Repeat all baseline measures at 3 months and annually thereafter 6

Tolerability During Initiation

Days 1-7 (After First Injection)

• Common adverse events include injection site pain (6.7% vs. 3.8% placebo), headache (4.0% vs. 3.8% placebo), and agitation (3.2% vs. 1.3% placebo) 5

Days 8-36 (After Second Injection, 156 mg Group)

• Common adverse events include anxiety (3.1%), psychotic disorder (2.5%), dizziness (2.5%), and injection site pain (2.5%) 5
• No unexpected tolerability findings were noted in the first week or month after initiation dosing 5

Critical Clinical Pitfalls to Avoid

• Never administer the initial two loading doses into the gluteal muscle - deltoid administration is required for Days 1 and 8 to achieve rapid therapeutic concentrations due to 28% higher maximum concentration compared to gluteal injection 4
• Do not supplement with oral antipsychotics during initiation - the loading dose strategy is specifically designed to achieve therapeutic levels without oral supplementation 1, 2, 4
• Do not skip or significantly delay the Day 8 injection - this second loading dose is essential for maintaining therapeutic plasma concentrations during the first month 1, 2
• Ensure proper needle selection based on patient weight - inadequate needle length may result in subcutaneous rather than intramuscular administration, compromising drug absorption 1, 2