Antipsychotics depot

Moore DB, Kelly DL, Sherr JD, et al (1998). Rehospitalization rates for depot antipsychotics and pharmacoeconomic... 

Chiu et al, 1992 Lin Finder, 1983 Lin et al, 1988b Potkin et al, 1984 Lin etal., 1989 Ruiz et al, 1996 Jann et al, 1989 Jann etal, 1992 Zhang-Wong etal., 1998). The majority of these studies were carried out with haloperidol. A number of studies examined differences between Caucasians and Hispanics, and African Americans and Caucasians (Midha et al., 1988b Midha etal, 1988a Ruiz et al., 1996). In general these studies provided mixed results. Another noteworthy feature of the research literature is that there appear to be no studies that have considered ethnic differences in pharmacokinetics and response for the depot antipsychotics. This may be an artifact of the low levels of depot prescribing found in the US, China, and Japan. 

Across the sites, an average of 15% of inpatients received depot antipsychotic drugs (Sim etal, 2004b). This was most common in Singapore (75%) followed by Taiwan (20%), Japan and China (6%). The depot antipsychotic drugs used were fluphenazine decanoate, flupenthixol decanoate, zuclopenthixol decanoate, haloperidol decanoate, pipothiazine palmitate, and fluphenazine enanthate. 

Intramuscular (IM) Into skeletal muscle. This route is used to deliver depot antipsychotic drugs like fluphenazine and haloperidol decanoate, which are used in the treatment of schizophrenia. 

Depot antipsychotics (e.g., haloperidol decanoate, fluphenazine decanoate, and risperidone long-acting injection) can be used for maintenance therapy of bipolar disorder with noncompliance or treatment resistance. 

Switching from other antipsychotics - The period of overlapping antipsychotic administration should be minimized. When switching patients with schizophrenia from depot antipsychotics, if medically appropriate, initiate quetiapine therapy in place of the next scheduled injection. Periodically reevaluate the need for continuing existing EPS medication. 

A high risk of relapse is inherent to schizophrenic psychoses. A relapse is often triggered by emotional stress. It is very important to prevent a relapse by either maintaining low-dose oral medication or by switching to a depot antipsychotic. In some cases, this cannot be avoided. Especially when compliance is a problem, a depot medication may help to keep the patient free of psychotic symptoms. Frequently used depot antipsy-chotics are haloperidol-decanoate, fluphenazine-decanoate, and fluspirilene, which are given in relatively low dosages (see Table 41.4). In EOS, relapse prevention is more important than in adulthood, as the majority of patients have not yet finished school or started a professional career. 

In the Expert Consensus survey (Rush and Frances, 2000) the expert clinicians rated newer atypical antipsychotics highest for treatment of schizophrenic patients who are compliant with medication. Risperidone was rated highest of the atypicals, followed by olanzapine. In the case of patients with numerous failed trials with other antipsychotics, the experts voted for clozapine. For patients noncompliant with oral medication, respondents endorsed long-acting depot antipsychotics. Once again, these were impressions based on personal clinical experiences rather than hard empirical data. 

Bioequivalence (e.g. equivalence of efficacy) of two different galenical formulations of the same compound as measured by maintained remission rates in schizophrenic patients after an oral or depot antipsychotic formulation. 

A parenteral, depot antipsychotic is one that can be administered in such a way that, after a single dose, a therapeutically efficient tissue concentration of at least 1 week s duration is achieved (251,252). Slow release of the active drug is produced by combining the base antipsychotic with a fatty acid (decanoic acid). The alcohol group of the antipsychotic is esterified by the acid, producing a lipophilic compound whose solubility in oil is increased. An oil, usually sesame, is then used as a vehicle for intramuscular injection, where the ester, which is not pharmacologically active, is hydrolyzed by tissue esterases, slowly releasing the active compound. An alternative technique is the use of microspheres (e.g., risperidone). 

Another area of continuing use of conventional antipsychotics is for the noncom-pliant patient who may require monthly injections of a depot antipsychotic. No atypical antipsychotic is yet available for depot administration, although such formulations are under development. Otherwise, most clinicians generally try several different atypical antipsychotics before resorting to a trial of clozapine (with its encumbrance of weekly or biweekly blood counts), conventional antipsychotics, or various combination therapies of atypical antipsychotics with other agents (Fig. 11 — 52 second- and third-line treatments). 

Bloch Y, Levkovitz Y, Atshuler A, et al. Use of topical application of lidocaine-prilocaine cream to reduce injection-site pain of depot antipsychotics. Psychiatr Serv. 2004 55 940-941. 

Barnes TR, Curson DA (1994) Long-term depot antipsychotics. A risk-benefit assessment. Drug Saf 10(6) 464-479... 

The most important action is to ensure that the client receives appropriate pharmacological treatment. One of the main problems in schizophrenia is lack of medication compliance. This is often caused by lack of client collaboration, often explained by the intrinsic pathological characteristics of the disease itself. Both typical and atypical depot antipsychotics formulations are available. Depot preparations are typically administered by intramuscular injection every 1-4 weeks. This may be of great advantage in patients with poor compliance. 

Al-Sughayir MA. Depot antipsychotics. Patient characteristics and prescribing pattern. Saudi Med J... 

Turner M, Eerdekens E, Jacko M, Eerdekens M. Long-acting injectable risperidone safety and efficacy in stable patients switched from conventional depot antipsychotics. Int Clin Psychopharmacol 2004 19 241-9. 

CLOZAPINE DEPOT ANTIPSYCHOTICS Risk of prolonged bone marrow toxicity Additive effect Avoid co-administration... 

Intramuscular initial dose 20 mg for pafienfs who have not been exposed to long-acting depot antipsychotics, 40 mg for patients who have previously demonstrated tolerance to long-acting depot antipsychotics after 4-10 days can give additional 20 mg dose maximum 200 mg every 1-4 weeks... 

Silverstone, T., G. Smith and E. Goodall (1988). Prevalence of obesity in patients receiving depot antipsychotics. Br J Psychiatry 153 214-7. 

I With zero-order kinetics (see Fig. 2.1) a fixed amount of drag is absorbed or ehminated for each unit of time independent of drag concentrations, because of some other rate-limiting factor. Examples are the metabolism of alcohol and phenytoin (saturation of metabolic enzymes) and absorption of controlled-release drags and depot antipsychotics. 

Chlorpromazine is well absorbed mainly from the jejunum. It is extensively metabolized in the liver, which produces several active metabolites. When given intramuscularly, the phenothiazine neuroleptics avoid metabolic degradation (first-pass metabolism), making them more beneficial as long-acting depot antipsychotics (see Table 2). 

UK manufacturer lists carbamazepine (see also Clozapine + Anti epileptics , p.744), chloramphenicol, cytotoxics, penicillamine, pyrazolone analgesics (e.g. phenylbutazone), sulphonamides (e.g. co-trimoxazole) and, because they cannot be stopped if an adverse reaction occurs, they advise against the use of depot antipsychotics. There are several cases that confirm the clinical significance of these predicted interactions. 

Table B.1.2 Depot antipsychotics - approximate relative side effects...

Few serious interactions, but discuss with pharmacy if SSRls, carbamazepine, phenytoin, ciprofloxacin, erythromycin, chemotherapy or depot antipsychotics... 

Products costing > 200/month for maximum dose, at time of going to press Table B.3 Common depot antipsychotics - key information... 

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