Research shows long-acting injectable risperidone could reduce schizophrenia relapse better than quetiapine

Recent research suggests that the rate of relapse in individuals with schizophrenia is 50% lower for patients injected every 2 weeks with risperidone, than for patients prescribed twice-daily doses of orally ingested quetiapine.1 The reasons for this difference are likely to be related to the high rate of relapse in schizophrenia patients who are non-compliant with self-administered drug therapy.2

Schizophrenia is a serious mental illness that affects approximately 1 to 2 in 100 Australians.^3,4 The onset of schizophrenia is around the late teens and early twenties for males, and the late twenties to mid-thirties for females.³ The incidence of schizophrenia is higher in males than in females, higher for migrants than for native-born people, and higher in urban regions than in rural regions.⁵

Medication is typically used to reduce symptom severity during a psychotic episode and is continued after the psychosis has resolved to prevent relapse. However non-compliance or only partial compliance with drug therapy regimens often hinder the treatment and subsequent recovery of patients with schizophrenia. Reasons for non-compliance may include a lack of insight into the need for medication, denial that they are ill, embarrassment at taking medication every day, or forgetting to take their medication.⁶

A recent study, presented in May 2008 at the American Psychiatric Association conference in Washington DC suggests that one way to avoid problems with medication non-compliance might be to use long-acting injectable medications that can be administered far less frequently than tablets or capsules.¹ The research followed patients in several European psychiatric treatment centres for 24 months. Researchers measured the relapse rates of 710 patients randomly allocated to one of two treatment groups that received either risperidone long-acting injection (RLAI) administered once a fortnight (n=329), or quetiapine administered twice daily (n=337). The dosages administered across the 24-month trial were varied according to the needs of the individual patient. The mean end-point dosage of risperidone long acting injection was 32.7mg, whereas the mean end-point dosage of quetiapine was 397mg.¹

Researchers assessed patients every 3 months on outcome measures including the PANSS (Positive and Negative Symptom Scale) and the CGI-S (Clinical Global Impression of Severity). Vital signs and BMI were also measured every 3 months. Relapse was defined as a psychiatric hospitalisation, suicidal or homicidal ideation, self-injury, violent behaviour, an increase in level of care necessary (a 25% increase in PANSS score), or significant clinical deterioration (a score of 6 on CGI-S).¹

Across the 2 years, relapse occurred in 16.5% of patients in the risperidone long acting injection group, and 31.3% of patients in the quetiapine group. Mean time to relapse was 607 days and 533 days in the risperidone long acting injection and quetiapine groups, respectively. Similar rates of discontinuation were reported in the two groups (32%). Similar rates of side effects including headache and weight gain were reported in both groups (6-7%). Higher rates of somnolence reported were by patients using quetiapine (11%; versus 2% for patients using risperidone). Both drugs were declared safe and well tolerated by the research team.¹

This research indicates that treatment with risperidone long-acting injection significantly prolongs time to relapse in patients with schizophrenia. Further, patients treated with risperidone (versus those receiving quetiapine) were half as likely to relapse.¹ These results suggest that injectable risperidone may be a useful alternative treatment to traditional, orally-administered, schizophrenia medications.

References

1. Medori R, Wapenaar R, de Arce R, Rouillon F, Gaebel W, Cordes J et al.  Relapse Prevention and Effectiveness in Schizophrenia with Risperidone Long-Acting Injectable (RLAI) Versus Quetiapine. Poster presented at 161st Annual American Psychiatric Association Meeting, 2008, Washington DC, USA
2. Leucht S, Heres S. Epidemiology, clinical consequences, and psychosocial treatment of nonadherence in schizophrenia. J Clin. Psychiatry 2006; 67 (Suppl 5):3-8.
3. The Mental Illness Fellowship of Australia Inc. [homepage on the Internet]. South Australia: Mental Illness Fellowship of Australia Inc; c2004 [cited 2008 Jun 17]. Understanding Schizophrenia. Available from: http://esvc000144.wic027u.server-web.com/papers_the_fact_sheets.htm
4. The Howard Florey Institute [homepage on the Internet]. Melbourne: Howard Florey Institute [cited 2008 Jun 17]. Schizophrenia; [about 2 screens]. Available from: http://www.florey.edu.au/the-brain/brain-disorders/schizophrenia/
5. McGrath J, Saha S, Welham J, El Saadi O, MacCauley C, Chant D. (2004) A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology. BMC Medicine. 2004 Apr 28; 2(1):13.
6. Rummel-Kluge C, Schuster T, Peters S, Kissling W. Partial compliance with antipsychotic medication is common in patients with schizophrenia. Australian and New Zealand Journal of Psychiatry. 2008 May; 42(5):382-388.