What is the recommended dosage of Invega (paliperidone) for adults with schizophrenia or schizoaffective disorder?

Invega (Paliperidone) Dosage for Schizophrenia and Schizoaffective Disorder

For adults with schizophrenia, start Invega at 6 mg once daily without initial titration, and for schizoaffective disorder, also start at 6 mg once daily—both can be adjusted within a range of 3-12 mg/day based on clinical response after at least 4 weeks at therapeutic doses. 1

Adult Dosing for Schizophrenia

• Initial dose: 6 mg once daily with no titration required 1
• The medication can be taken with or without food and must be swallowed whole—never chewed, divided, or crushed 1
• Dose adjustments: If needed after clinical reassessment, increase in 3 mg/day increments at intervals of more than 5 days 1
• Dose range: 3-12 mg/day, with some patients responding adequately to 3 mg/day while others may benefit from doses up to 12 mg/day 1
• Maximum dose: 12 mg/day 1
• Higher doses show a general trend for greater effects but must be weighed against dose-related increases in adverse reactions, particularly extrapyramidal symptoms 1, 2

Adult Dosing for Schizoaffective Disorder

• Initial dose: 6 mg once daily without titration 1
• Dose range: 3-12 mg/day based on clinical response 1
• Dose increases, if indicated, should occur at intervals of more than 4 days in 3 mg/day increments 1
• Maximum dose: 12 mg/day 1
• Can be used as monotherapy or as adjunct to mood stabilizers and/or antidepressants 1

Adolescent Dosing (Ages 12-17) for Schizophrenia

• Initial dose: 3 mg once daily without titration 1
• Dose increases should only occur after clinical reassessment, in 3 mg/day increments at intervals of more than 5 days 1
• Important caveat: In adolescent trials, higher doses (6 mg for patients <51 kg and 12 mg for patients ≥51 kg) showed no clear enhancement in efficacy while adverse events were dose-related 1

Treatment Duration and Efficacy Assessment

• Maintain therapeutic doses for at least 4 weeks before determining efficacy and considering a switch to another antipsychotic 3, 4
• This 4-week minimum applies when good adherence is documented 4
• If switching from a D2 partial agonist as first-line treatment, paliperidone is an appropriate second-line option 3, 4
• Gradual cross-titration is recommended when switching, informed by the half-life and receptor profile of each medication 3

Special Population Dosing Adjustments

Renal Impairment

• Mild impairment (CrCl 50-79 mL/min): Start at 3 mg once daily, maximum 6 mg/day 1
• Moderate to severe impairment (CrCl 10-49 mL/min): Start at 1.5 mg once daily, maximum 3 mg/day 1
• CrCl <10 mL/min: Not recommended (not studied) 1

Hepatic Impairment

• Mild to moderate (Child-Pugh A and B): No dose adjustment needed 1
• Severe hepatic impairment: Not studied 1

Elderly Patients

• Use same dosing as younger adults if renal function is normal 1
• Adjust dose according to renal function status, as elderly patients may have diminished renal function 1
• For moderate to severe renal impairment, maximum dose is 3 mg once daily 1

Critical Considerations

• Do not combine with risperidone without considering additive paliperidone exposure, as paliperidone is risperidone's major active metabolite 1
• Paliperidone undergoes limited hepatic metabolism, minimizing risks of hepatic drug-drug interactions compared to risperidone 5
• The extended-release formulation provides stable plasma concentrations over 24 hours with peak levels at approximately 24 hours post-dose 5
• Terminal half-life is approximately 23 hours, and renal excretion is the major route of elimination 5
• Common adverse events include extrapyramidal symptoms (particularly at 9-12 mg/day doses), tachycardia, somnolence, headache, tremor, and akathisia 2, 6
• Increases in serum prolactin levels occur similar to risperidone 2, 6