Paliperidone Long Acting Injections (Sustenna / Trinza / Hafyera) – Psychopharmacology and Clinical Application

Posted on:December 17, 2021
Last Updated: December 20, 2021
Time to read: 11–13 minutes

Paliperidone long-acting injections (LAIs) are available in three forms (1 monthly, 3 monthly and 6 monthly injectable forms). All three forms contain a racemic mixture of (+)- and (-)- paliperidone palmitate.

Paliperidone palmitate is an atypical long-acting injectable antipsychotic (LAIA) approved for acute and maintenance therapy of schizophrenia and schizoaffective disorder. Paliperidone palmitate comes as an aqueous suspension of nanocrystals that are 10 times smaller than standard drug powders and therefore have an increased drug-solution surface area. 

  • The advantages of LAIAs include longer intervals between treatments, easy applicability, and enhanced patient compliance. [Newton et al. 2012] 
  • Paliperidone palmitate is well tolerated with a safety profile that is not different from oral paliperidone or risperidone. [Nussbaum and Stroup 2012] 

Paliperidone palmitate is a prodrug of paliperidone (a benzisoxazole derivative), which is also the major active metabolite of risperidone. The addition of a palmitoyl ester results in very low water solubility, which means it has extended-release properties and therefore can be dosed as a long-acting injection. [Hough et al. 2009] 

Due to the extremely low water solubility, the 1 month, 3-month, and 6-month formulation of paliperidone palmitate dissolves slowly after intramuscular injection before being hydrolysed to paliperidone and absorbed into the systemic circulation.