Modification of long-acting injectable antipsychotic therapy for recovery and relapse prevention in adults and young people

Long-acting injectable antipsychotics take weeks to months to reach steady-state concentration, depending on the half-life of the drug and the formulation; check a drug information resource for detail. Dosage adjustments should be guided by response to therapy and tolerability (regularly monitor for adverse effects). Avoid dosage adjustments before steady state has been reached; this increases the risk of adverse effects (when dosage is increased) or compromised symptom control (when dosage is reduced). Once steady state is reached, antipsychotic blood concentration monitoring may assist dosage adjustment¹².

Breakthrough psychotic symptoms occur in up to 30% of patients treated with a long-acting injectable antipsychotic, most commonly in the first year of the disorder. Treat breakthrough symptoms by adding an oral dose of the long-acting injectable antipsychotic (if possible), and, if steady state has been reached, simultaneously increasing the long-acting injectable dose. Reduce the oral supplementation dose over weeks to months while steady state of the long-acting injectable antipsychotic is reached. The combined oral dose and long-acting injectable dose should not exceed the maximum dose of the drug.

• For oral and long-acting injectable dose equivalencies, see Approximate equivalent oral and long-acting injectable dosages for some antipsychotics.
• For maximum oral doses, see ../First-episode-of-psychosis/c_ptg8-c49-s5.html#ptg8-c49-s5__tptg8-c49-tbl3.
• For maximum long-acting injectable doses, see here.

Breakthrough psychotic symptoms can progress to a full relapse.