Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
7.5 Major clinical issues with psychosis and opioid use
Table of contents
- Acknowledgments
- Abbreviations
- Preface
- Introduction
1. Levels of evidence- 2. Management of people with comorbidity of mental disorders and substance use
- 3. The common drug groups
- 4. Tobacco
- 5. Depression and substance use
- 6. Anxiety disorders and substance use
7. Psychosis (schizophrenia and bipolar disorder) and substance use- 7.1 Psychosis
- 7.2 Comorbidity with Psychosis
- 7.3 Major clinical issues with psychosis and cannabis/ hallucinogen use
- 7.4 Major clinical issues with psychosis and alcohol use
- 7.5 Major clinical issues with psychosis and opioid use
- 7.6 Major clinical issues with psychosis and stimulant (including methampetamine) use
- 7.7 Major clinical issues with psychosis and benzodiazepine use
- 7.8 Major clinical issues with psychosis and inhalent/ solvent use
- 8. Personality disorders and substance use
- 9. Eating disorders and substance use
- 10. Somatoform disorders and substance use
- 11. Gambling and substance use
- 12. Brain injury, mental disorders and substance use
- 13. Bibliography
- 14. Appendices
- Concurrent opioid dependence and psychotic disorders are often associated with high levels of dysfunction.
- Opioids (including methadone and buprenorphine) will exacerbate the sedative effects of antipsychotics.
- Carbamazepine is a potent CYP inducer and will induce the metabolism of methadone and buprenorphine as well as reduce plasma concentrations.
- Early studies show olanzapine, in combination with opioid maintenance pharmacotherapies, to be effective in controlling illicit opioid use and symptoms of psychosis.
- Combined daily dispensing of psychotropic medication at the same time as daily dispensing of opioid maintenance pharmacotherapy may improve treatment compliance for the psychotic disorder.
7.5.1 Effects of opioids on psychotic disorders
- The prevalence of comorbid psychosis and opioid use is generally low(263).
- However, comorbid psychosis and opioid use is associated with increased mortality(305).
- Concurrent opioid dependence and psychotic disorders are often associated with high levels of dysfunction.
7.5.2 Interactions between opioids and therapeutic agents for psychotic disorders
- Opioids (including methadone and buprenorphine) will exacerbate the sedative effects of antipsychoticsx.
- Carbamazepine is a potent CYP inducer and will induce the metabolism of methadone and buprenorphine as well as reduce plasma concentrationsxx(149, 157). This has the potential to result in withdrawal and failure of retention in treatment****(158-160).
- There do not appear to be any interactions between naltrexone and antipsychotics.
- Opioids can exacerbate the sedative effects of tricyclic antidepressants and benzodiazepines used to treat breakthrough depression(2) and anxiety in psychosis which increases the risk of overdosex.
- Methadone itself has been shown to inhibit CYP3A4xx(240, 241) which also metabolises many benzodiazepines. This has the potential to increase both the plasma concentrations of benzodiazepines and their sedative effectsx(242, 243).
- Several deaths have been reported due to benzodiazepine use in conjunction with high dose buprenorphine and may be a result of similar metabolic interactionsxxx(244-246).
- Fluvoxamine xxx, fluoxetinexx, norfluoxetinexx and paroxetinex can inhibit buprenorphine and methadone metabolism through inhibition of the CYPs involved in their metabolism(148-150). This can result in an increase in plasma opioid pharmacotherapy concentrations and potential overdose. This can be a particular issue during induction onto methadone; however, the risk may persist even after stabilisation has occurredxxx(151-155).
- Fluvoxamine is the most potent inhibitor of methadone and buprenorphine metabolism and is the most clinically relevant. Therefore, it should be avoidedxxx(150).
- Fluoxetine and paroxetine should also be avoidedxx.
- Citalopram and sertraline are the least likely SSRIs to have cytochrome mediated drug interactions; however, due to the theoretical potential for an interaction, caution should still be used and individuals monitored closelyx(156).
7.5.3 Management approaches to comorbid psychotic disorders and opioid use
- There is little research assessing the management of opioid use and psychosis. However, those with psychosis who participate in methadone treatment do not appear to experience any more side effects than those without comorbid psychosis and can benefit from opioid maintenance therapy(2, 306).
- Buprenorphine has yet to be studied in people with comorbid opioid dependence and schizophrenia(271).
- Early studies show olanzapine, in combination with opioid maintenance pharmacotherapies, to be effective in controlling illicit opioid use and symptoms of psychosis**(307).
- Close liaison between the prescriber and the pharmacist dispensing the opioid maintenance will assist with gaining insight into adherence to treatment, levels of self care and general stability.
- While there have been no studies to assess the impact on psychosis treatment compliance, combined daily dispensing of psychotropic medication at the same time as daily dispensing of opioid maintenance pharmacotherapy may improve treatment compliance for the psychotic disorder.
- Benzodiazepines prescribed for acute opioid withdrawal in individuals with psychosis should be monitored closely and minimised for outpatient use(2).
- The use of benzodiazepines should be restricted to short-term symptomatic use only, as those with substance-use disorders are at greater risk of abusing benzodiazepines(196).
