Pharmacokinetics of long-acting injectable neuroleptic drugs: clinical implications

The authors review the literature regarding the pharmacokinetics of long-acting injectable neuroleptic drugs (LINS). There are important differences between LINS and oral neuroleptics that affect their pharmacokinetics. By avoiding first pass metabolism in gut and liver, LINS result in lower circulating concentrations of metabolites than are found after oral administration. In addition, LINS take more time to reach a stable steady state than their oral counterparts. The clinical significance of these pharmacokinetic properties is discussed. The authors recommend that when patients are being changed from oral neuroleptics to LINS, that this conversion be done gradually over several months.