Paliperidone: A Clinical Review

Paliperidone is an antipsychotic recently made available in the US and UK in a special oral extended release form. Paliperidone is a modified form of risperidone namely 9-hydroxyrisperidone, (itself the active metabolite of risperidone). Since risperidone has been available for many years some argue that paliperidone is not a novel antipsychotic but a newly marketed variant. An injectable form, paliperidone palmitate is being trialled. Paliperidone is mainly excreted renally and there is only limited hepatic metabolism. Paliperidone works by partially blocking D2 dopamine receptors and fully blocking serotonin. The normal dosing range for paliperidone is 3-12 mg daily. Efficacy studies with paliperidone indicate that it is effective against schizophrenia and also has a similar side effect profile compared to other antipsychotics. There is an absence of effects on glucose and lipids in comparison with olanzapine. Symptom reduction in schizophrenia occurs as soon as day four of treatment with paliperidone. Clinical experience with risperidone over many years suggests that paliperidone would have a valuable role as an antipsychotic. The entity is not truly novel, but rather than being a variant existing purely for marketing purposes, should be regarded as an upgrade.