Document level: Drug Alcohol (Trustwide) Code: DA7 Issue number: 2 Guidance for naltrexone prescribing Lead executive Authors details Type of document Target audience Document purpose Lead Clinical Director Medical Officer in Substance Misuse Guidance Community Drug and Alcohol Team Staff To provide guidance for prescribing of naltrexone for opiate dependence in the post detoxification period. Approving meeting Medicines Management Group Date 12-Jun-14 Implementation date Jun-2017 CWP documents to be read in conjunction with DA3 Guidance for the Management of Community Opiate Detoxification Document change history What is different? Appendices / electronic forms What is the impact of change? New document New doucment New document To view the documents Equality Impact Assessment (EIA) and see who the document was consulted with during the review please click here Page 1 of 5 Do not retain a paper version of this document, always view policy / guidance documents from the desktop icon on your computer
Content Quick reference flowchart for guidance for naltrexone prescribing... 3 1. Introduction... 4 2. Overview... 4 3. Pharmacology... 4 4. Contra Indications... 4 5. Cautions... 4 6. Preparation of patients... 5 7. Ongoing care... 5 Page 2 of 5 Do not retain a paper version of this document, always view policy / guidance documents from the desktop icon on your computer
Quick reference flowchart for guidance for naltrexone prescribing For quick reference the guide below is a summary of actions required. Page 3 of 5
1. Introduction This document refers to the use of Naltrexone as part of a comprehensive relapse prevention package. 2. Overview The risk of relapse into drug use following detoxification remains high and puts patients at many risks, most ostensibly risk of fatal overdose. In extending periods of abstinence these risks can be reduced and positive lifestyle changes may be facilitated. NICE recommend that "naltrexone is a treatment option for people who have been opioid dependent but who have stopped using drugs and are highly motivated to stay free from drugs in an abstinence programme" i.e. as part of a package including psychosocial interventions. The 'Summary of product characteristics' (SPC) states that naltrexone is licensed for use as an adjunctive prophylactic treatment for detoxified formerly opioid-dependent people (who have remained opioid free for at least 7 10 days). 3. Pharmacology Naltrexone is an opioid antagonist with a high affinity for opioid receptors. It competitively displaces opioid agonists and therefore blocks the effects of opioids (euphoric and otherwise) and therefore inhibits the reward pathways associated with opioid use. The blockade is competitive and therefore patients must be advised that attempting to overcome the blockade (with opioids) dramatically increases the risk of overdose. It is presented as a 50mg tablet for oral consumption on a daily basis. 4. Contra Indications See BNF for full list, includes: Patients currently dependent on opioids; Acute hepatitis, hepatic failure or severe impairment (i.e. those patients will have physical signs of liver failure, e.g. jaundice, symptoms of portal hypertension or other stigmata of liver disease); Severe renal impairment; Breast feeding. The BNF states "In pregnancy it should only be used if benefit outweighs risk". It would be sensible to avoid use where there has been a previous allergic response to naltrexone (this does not include a previous adverse reaction resulting from taking naltrexone whilst using opioid drugs). 5. Cautions Due to the potentially hepatotoxic nature of naltrexone, liver function tests are needed before and during treatment (at 4wks and then 6 monthly). Caution should be used in prescribing naltrexone in patients with abnormal liver function tests (e.g. more frequent review and testing). Caution should be used in patients who take opiate based analgesia on a regular basis. Side Effects: See BNF for full list. Includes; nausea, vomiting, abdominal pain, diarrhoea, constipation, anorexia, chest pain, anxiety, sleep disorders, rash, increased sweating; very rarely hallucinations, tremor and idiopathic thrombocytopenia. Page 4 of 5
6. Preparation of patients Patients should be made aware of the option of naltrexone as part of their comprehensive relapse prevention package when formulating their detoxification plan. Prior to prescribing there should be an in depth discussion including the mode of action, risks and benefits of treatment with naltrexone and particularly the risks of concurrent opioid use, how it should be taken and the potential side effects. The discussion should be documented and written information should also be supplied. The patient should have had liver function tests carried out in the 6 months prior to commencement; the levels of GGT and ALT should be NO greater than three times the upper limit of normal range. Enquire about the possibility of the patient being pregnant. It may be appropriate to use a pregnancy test. Ensure there are no other medical contraindications. The patient should have completed opioid detoxification with the following minimum periods from opioid use: Heroin: Methadone: Buprenorphine: Codeine: 7 days 10 days 3-5 days 7 days A negative urine drug screen is essential within 12 hours of initiating naltrexone, ideally supported by a negative screen in the 7 days prior to commencement. The dose is 25mg initially and then 50mg daily thereafter. Ideally naltrexone should be supervised by health care worker or responsible relative. Ensure that the patient has a caution card supplied by the manufacturer; the patient should be advised to carry this card at all times. Ensure that any relevant health care professionals are informed (this will usually be the patient s GP who will be sent a copy of the prescriber s CareNotes entry). 7. Ongoing care Patients should continue to access recovery focused support as per their relapse prevention plan. Patients should be reviewed in clinic, with liver function test results at 4 weeks, further blood screening as detailed earlier. Naltrexone can be continued for at least 6 12 months provided there is no relapse. Prescribing will normally revert to the General Practitioner after 4 weeks. Page 5 of 5