1st of a 4pt series on Medications used for treating / managing Schizophrenia

Medication used for schizophrenia Part 1

In many cases, people living schizophrenia do not realise they have a mental illness. They may not think they need help because they believe their delusions or hallucinations are real. Therefore, it is often up to family and friends to seek treatment. Occasionally people with schizophrenia pose an immediate risk to themselves or others during an acute episode and may need rapid tranquillisation. Tranquillisation with benzodiazepines should only be a temporary measure.

The causes of schizophrenia are still unknown; therefore, treatment focuses on eliminating the symptoms of the disease. Antipsychotics are mainly used to treat schizophrenia. They work by altering the balance of some neurotransmitters in the brain thus controlling symptoms.  Positive symptoms respond well to antipsychotic drugs however they do not work as well on negative symptoms. Therefore, antipsychotic medication is usually taken on a long-term basis thus preventing relapses. Antipsychotic drugs are broadly divided into two categories: typical or atypical antipsychotics.

Older typical antipsychotics

These are sometimes called first generation antipsychotics and were the first type of antipsychotics developed in the 1950s for psychosis, especially schizophrenia. Examples include chlorpromazine, trifluoperazine, haloperidol, flupentixol, zuclopenthixol, and sulpiride. 30% of patients have a relapse during treatment with first-generation antipsychotic drugs compared with 80% without treatment.

Newer atypical antipsychotics

These were first introduced in the 1990’s and are also known as second generation antipsychotics. Examples are amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, and risperidone. Atypical antipsychotics are often used first-line for newly diagnosed schizophrenia. This is because they demonstrate good balance between chance of success and the risk of side-effects. However, for people already stabilised on typical antipsychotic there is no need to change to a newer one.

Depot injections of an antipsychotic drug

In some cases, an injection of a long-acting antipsychotic drug is used once symptoms have eased. The drug from a depot injection is slowly released into the body and is given every 2 to 4 weeks. This aims to prevent relapses. The main advantage is that it prevents the problem of non-compliance. Non-compliance can be a problem with schizophrenia as the patient may not realise they have a problem. An American study showed that 74% of patients with schizophrenia discontinued medication within 18 months without consulting with their doctor leading to relapses. Non-compliance is similar for atypical and typical antipsychotics; therefore, depot injections can be a solution where compliance is a problem.

There are five FGA depot injections and two SGAs (risperidone (Risperdal Consta^®) and paliperidone (Xeplion^®)) available in Ireland as a long-acting injection (LAI).

Second-generation long-acting antipsychotic injections (SGAs)

Risperidone injection

Risperidone was the first second generation LAI to be licensed in the UK and Ireland. The risperidone LAI antipsychotic works in a separate way to the first-generation depot injections.  The drug will not reach a therapeutic level for a few weeks after injection; therefore, it is essential that the patient receive alternative antipsychotic medication during the initial period of treatment following the first injection.

Paliperidone injection

Paliperidone injection blocks serotonin 5-HT₂ and dopamine D₂ receptors. Dopamine and serotonin are neurotransmitters known to be involved in regulating mood and behaviour, amongst other things. Paliperidone is effective in relieving both positive and negative symptoms of schizophrenia, whereas older antipsychotics are usually less effective against the negative symptoms. Paliperidone also relieves 'affective symptoms' that are associated with schizophrenia, such as depression, guilt feelings or anxiety. Paliperidone injection is administered into the muscle of the upper arm or buttock, where it forms a reservoir of medicine that is slowly released into the bloodstream. The injection is given once every four weeks.

Patient suitability:

Paliperidone LAI has not been shown to be any more efficacious than risperidone long acting injection but does have some practical advantages including the fact it does not have to be stored in the fridge, it is only administered once monthly and comes as a pre-filled syringe meaning administration is easier and quicker. There are no data on efficacy in prevention of relapse relative to other long acting injections.

To be continued next week

For comprehensive and free health advice and information call in to Whelehans Pharmacies, log on to www.whelehans.ie or dial 04493 34591 (Pearse St) or 04493 10266 (Clonmore).