TREATMENT OF SCHIZOPHRENIA

GUIDELINES FOR PRESCRIBING ATYPICAL ANTIPSYCHOTIC AGENTS FOR ADULTS IN XXXXX NHS TRUST

Attached to these guidelines is an algorithm relating to the choice of antipsychotic drug therapy in schizophrenia and a list of antipsychotic drug costs.

The evidence base suggests that atypical antipsychotics are as effective in the treatment of schizophrenia as haloperidol but that they cause fewer extra-pyramidal side effects (EPSEs) and side effects relating to hyperprolactinaemia. The clinical use of the atypical antipsychotics, risperidone and olanzapine, is now well established in XXXXX. There is no clear evidence that amisulpride, quetiapine and zotepine have any advantages in this respect over these two established agents.

Treatment with atypical antipsychotic therapy should only be initiated by CONSULTANT PSYCHIATRISTS following consultation with the multidisciplinary team.

CHOICE OF PATIENT

First episode treatment would normally be with a typical antipsychotic (see algorithm) except in special circumstances

(NB NEEDS AGREED LIST OF SPECIAL CIRCUMSTANCES)

Atypical antipsychotic therapy should be reserved for patients shown to be

PRIOR TO COMMENCING THERAPY

MONOTHERAPY

Best practice suggests the use of one antipsychotic agent in monotherapy. If an atypical agent is added into treatment with a typical antipsychotic, after a reasonable change over period, the typical antipychotic should be reduced and stopped. The benefits of atypical antipsychotic agents may be negated by polypharmacy. There is currently no evidence that supports the concurrent prescription of an atypical and a typical antipsychotic.

i.e. typical antipsychotics, including depots, should not be used together with atypical antipsychotics.

There is no evidence to suggest the use of more than one atypical antipsychotic for any patients.

COMMENCING THERAPY (Ref 1)

  1. Introduce drug
  2. Titrate to minimum effective dose (add sedative for behavioural control if required)
  3. Evaluate over at least two weeks
  4. If there is no response then increase dose by 25 to 50% according to the product information. Repeat evaluations and dose adjustments as necessary to maximum effective dose
  5. Evaluate over six weeks after dose titration

SWITCHING THERAPY

From oral typical to atypical

Start the atypical at the recommended dose. Gradually titrate the dose of the typical down over the first two weeks.

When the typical antipsychotic is discontinued gradually reduce the dose of any co-prescribed antimuscarinic over the next two weeks.

From depot typical to atypical

Start atypical on the day the depot would next have been due. When the atypical is at a therapeutic dose gradually reduce the dose of any co-prescribed antimuscarinic over the next two weeks.

LONG TERM TREATMENT

As atypical therapy will have been initiated by a consultant psychiatrist all patients will be covered by the care programme approach (CPA). The response to treatment can be monitored through the CPA and the use of the Health of the Nation Outcome Scales (HoNoS).

Atypical antipsychotics available in XXXXX in secondary and primary care

RISPERIDONE

Starting dose 2mg. The majority of patients respond to between 4-6mg/d.

Maximum effective dose 8mg/d although this is below BNF max.

There is evidence of increased EPSEs above 8mg

Tablets 1mg, 2mg, 3mg and 4mg Liquid 1mg/ml

OLANZAPINE

Starting dose 5 to 10mg. Majority of patients respond to 10mg but the dose range is less clear than with risperidone and some patients require higher doses.

Maximum BNF dose is 20mg.

CLOZAPINE

CLOZAPINE is the only antipsychotic available with clear evidence of efficacy in treatment resistant schizophrenia.

All prescriptions for clozapine are dispensed within secondary care

There are substantial risks associated with clozapine therapy which are attenuated by adherence to the Clozaril Patient Monitoring Service (CPMS).

Clozapine treatment should be reserved for patients with a clear diagnosis of treatment resistant schizophrenia including schizoaffective disorder. (No other patients will be considered for treatment with clozapine).

All patients considered for treatment with clozapine should have previously been prescribed a minimum of two antipsychotics at different times at an adequate therapeutic dose. The previous treatment has been ineffective or only partially effective.

Treatment with clozapine involves more risks to the patient than other antipsychotics and involves many healthcare professionals for treatment success. If successful treatment will be long term and it is essential that the most appropriate patients are chosen for treatment.

A full assessment must be carried out and preferably a care meeting held prior to the decision to treat with clozapine.

PRIOR TO TREATMENT WITH CLOZAPINE

TREATMENT WITH CLOZAPINE

Gradual titration is necessary with a daily starting dose of 12.5mg. The minimum effective dose usually around 300mg is reached two to three weeks after starting.

The special prescription chart can be used for the titration of clozapine therapy.

Check patients blood pressure, temperature and pulse regularly during dose titration.

Ensure other antipsychotics and antimuscarinics are gradually reduced (get mental health pharmacist advice).

Continue at this dose for 4 to 6 weeks and increase gradually (by 25mg per day) to 450mg only if necessary. Continue this process to a maximum daily dose of 900mg

At higher doses there is an increased risk of seizures. These may be treated with Sodium Valproate.

Many patients complain of hypersalivation which may be treated with low dose hyoscine available as 150 micrograms as Joy Rides and 300micrograms as Kwells. This is often a problem at night.

Introduce patient to clozapine clinic and familiarise patient with process that will occur following discharge. Ensure a plan for blood taking and supply of medication is in place. This must be communicated to all healthcare professionals (e.g. clozapine clinic, pharmacy, keyworker, GP) as well as to the patient and carers. if the patient is

PATIENT MONITORING (separate to the CPMS)

Prior to treatment as part of the care plan, carry out a Health of the Nation Outcome Score (HONOS). Use other rating scales if appropriate for the individual patient.

Repeat this at 18 weeks, 6 months, 1 year and then yearly thereafter as part of the care plan. The person responsible for the blood monitoring will send out reminders for the appropriate checks.

Ensure all healthcare professionals involved are aware of other medication that the client may be taking and that the GP and community pharmacist are aware of the prescription of clozapine.

AUDIT

Patients treated with clozapine will form part of a continuous audit process, allowing the benefits of clozapine to be gained whilst both minimising the risks to the patients and the costs to the trust and health authority.

March 2000