LONG-TERM DEPOT ANTIPSYCHOTICS - A RISK-BENEFIT ASSESSMENT

The main advantage of depot antipsychotic medication is that it overco mes the problem of covert noncompliance. Patients receiving depot trea tment who refuse their injection or fail to receive it for any other r eason can be immediately identified and appropriate action taken. In t he context of a carefully monitored management programme, depot treatm ent can have a major impact on compliance and, consequently, the risk of relapse and hospitalisation can be reduced. Another major advantage is that the considerable individual variation in bioavailability and metabolism with oral antipsychotic drugs is markedly reduced with depo t treatment. A better correlation between the dose administered and th e concentration of medication found in blood or plasma is achieved wit h depot treatment, and thus, the clinician has greater control over th e amount of drug being delivered to the site of activity. A further be nefit of depot treatment is the achievement of stable plasma concentra tions over long periods, allowing injections to be given every few wee ks. However, this also represents a potential disadvantage in that the re is a lack of flexibility of administration. Should adverse effects develop, the drug cannot be rapidly withdrawn. Furthermore, adjustment to the optimal dose becomes a long term strategy. The controlled stud ies of low dose maintenance therapy with depot treatment suggest that it can take months or years for the consequences of dose reduction, in terms of increased risk of relapse, to become manifest. When weighing up the risks and benefits of long term antipsychotic treatment for th e individual patient with schizophrenia, the clinician must take into account the nature, severity and frequency of past relapses, and the d egree of distress and disability related to any adverse effects. Howev er, the clinical decision to prescribe either a depot or an oral antip sychotic for maintenance treatment will probably rest largely on an as sessment of the risk of poor compliance in the particular patient. The re is no convincing evidence that the range, nature or severity of adv erse effects reported with depot treatment is significantly different from that seen with oral treatment, and depot treatment has been shown to be as good or better than oral medication in preventing or postpon ing relapse. Furthermore, when adjusting the dose or frequency of depo t injection, to improve control of psychotic symptoms or reduce advers e effects, the clinician can be confident that the dose prescribed is the dose being received by the patient.