Opioid dependence

Prescribing Notes:

• Patients with specific symptoms of opioid withdrawal, such as diarrhoea, nausea/vomiting or colic can be treated with loperamide, metoclopramide, hyosine butylbromide and mebeverine if required. Zopiclone may be prescribed if insomnia is a problem. Benzodiazepines should be avoided. High dose (opioid) heroin use in a patient admitted to an acute hospital may require a short-acting opioid substitute. This will make covert illicit supply to in-patients less likely, stop self-discharge against advice and improve management.
• Dihydrocodeine (rapid onset and short acting) is an option and advice should be sought from specialist services on appropriate dosing. It should not be continued on discharge. A positive test for opioids is required using urine dipsticks or toxicology prior to prescribing.
• A long-term prescription for substitute opioids should not be initiated until fully assessed by own GP or specialist substance misuse services.

Prescribing Notes:

General notes on opioid maintenance prescribing

• Refer to the current edition of Drug misuse and dependence: UK guidelines on clinical management (Department of Health). Prescriptions should be considered only after the patient has been fully assessed and has shown evidence of opioid dependence and motivation to stabilise their drug use.
• Although abstinence may be the eventual aim of treatment, management should involve regular assessment and goal setting to help the patient to achieve stability and reduce harm.
• Treatment decisions should be made jointly with patient, ensuring patient choice.
• Methadone and oral buprenorphine should be administered daily, under supervision, generally for at least the first 3 months.
• After stabilisation, gradual dose reduction can be achieved with methadone or buprenorphine when the patient is ready.
• Take-home doses should not normally be prescribed where: a patient has not reached a stable dose; the patient shows a continued and unstable pattern of drug misuse, including a significant increase in alcohol intake, the use of illicit drugs, benzodiazepines or other tranquillisers; the patient has a significant, unstable psychiatric illness or is threatening self-harm; there is continuing concern that the prescribed medicine is being, or may be, diverted or used inappropriately; there are concerns about the safety of medicines stored in the home and possible risk to children.
• If a drug user, stable on a verified maintenance dose, is admitted to hospital this should be continued at the established dose after confirmation with the relevant prescriber and community pharmacist. Particular care should be taken in giving and receiving information on when patients have last been given doses during the transfer between community and hospital or vice versa. For the first few doses, patients should be confined to the ward for 2-4 hours after the dose to ensure no opioid toxicity. If a history of drug use is given by a patient not on prescribed treatment, refer to hospital policy or discuss with specialist substance misuse service.
• A ‘Take Home Naloxone’ programme is in place for persons at risk of opioid overdose. Naloxone is an opioid-receptor antagonist used to reverse opioid overdose. Patients’ dependant on opioids and their carers may be given a supply of naloxone to be used in case of accidental overdose. Patients and carers should undergo overdose recognition, basic life support and naloxone training in advance of receiving supply. See the ‘Opioid overdose - treatment with naloxone’ pathway for details.
• Refer to local guidance for Substitute Treatment Prescriptions for Patients making Holiday and Travel Arrangements within and outwith the United Kingdom for advice on travel arrangements, such as NHS Lothian intranet guidelines.

Methadone

• Methadone tablets should not be used for opioid maintenance prescribing.
• An ECG should be undertaken before dose titration above 100mg of methadone.
• If converting a patient from methadone to buprenorphine, seek specialist advice.
• Pain relief for patients on methadone is best provided by non-opioid analgesics such as aspirin, paracetamol or NSAIDs. For severe pain, doses of opioids larger than normal may be required. Seek specialist advice on pain management.

Buprenorphine and buprenorphine/naloxone

• Buprenorphine has both partial opioid agonist and antagonist activity. To avoid precipitating symptoms of withdrawal, it is essential that patients are withdrawn at the time of first dose (observable significant opioid withdrawal symptoms).
• For patients prescribed buprenorphine preparations, liver function tests should be undertaken at baseline and at regular interval throughout treatment.
• Espranor is restricted to patients in whom methadone is not suitable. Espranor is a suitable choice of buprenorphine formulation in patients for whom supervised dispensing is appropriate but the length of time the daily supervision process takes (for other available buprenorphine formulations) would adversely impact on employment, education or family commitments.
• Buvidal is restricted to adults and adolescents aged 16 years or over in whom methadone is not suitable and for whom the use of buprenorphine is considered appropriate.
• Buprenorphine and buprenorphine/naloxone oral preparations are appropriate for a shared care arrangement to facilitate the seamless transfer of individual patient care from secondary care to general practice (NHS Lothian).

Missed doses

• Patients who miss 3 days or more of their regular prescribed dose of opioid maintenance therapy are at risk of overdose because of loss of tolerance. Consider reducing the dose in these patients.
• If the patient misses 5 or more days of treatment, an assessment of illicit drug use is also recommended before restarting substitution therapy; this is particularly important for patients taking buprenorphine, because of the risk of precipitated withdrawal.

Prescribing Notes:

• See NICE Clinical Guideline 52: Drug Misuse - opioid detoxification.
• Community detoxification is a specialist intervention and requires close monitoring and support. It should not usually be attempted by GPs without specialist support.
• As per NICE CG52, ultra-rapid (24 hours) detoxification should not be offered and rapid (1-5 days) detoxification should not be routinely offered. Opioid detoxification in the community should be undertaken in up to 12 weeks.
• If receiving maintenance treatment with methadone or buprenorphine, the same drug should be used for detoxification, but patient preference should be taken into account.
• Buprenorphine has both partial opioid agonist and antagonist activity. To avoid precipitating symptoms of withdrawal, it is essential that patients are withdrawn at the time of first dose (observable significant opioid withdrawal symptoms). If switching from methadone to buprenorphine, the dose of methadone should normally be reduced to a maximum of 30mg daily before starting buprenorphine. If converting a patient from methadone to buprenorphine, seek specialist advice.
  
  

Prescribing Notes:

• For specialist initiation. Responsibility for prescribing and monitoring for the first three months of treatment remains with the specialist. Thereafter ongoing treatment can be prescribed in primary care by a GP with experience in management of drug dependency.
• Naltrexone can be prescribed for patients who have remained opioid free for at least 7-10 days.
• Patients need to be warned that an attempt to overcome the naltrexone block could result in acute opioid intoxication and the increased risk of overdose in the event of opiate lapse/relapse.
• After stopping naltrexone tolerance to opioids will be greatly reduced, patients restarting opioids will be at an increased risk of overdose.
• Initial dose should be given under medical supervision and the patient observed for at least one hour, because of the higher risk of adverse effects through the precipitation of acute prolonged opiate withdrawal syndrome.
• Liver function tests should be checked prior to initiation and monitored during treatment.
• Patient should carry an emergency medical card with them.

Prescribing Notes:

• The aim of the Take Home Naloxone (THN) programme is to reduce the number of fatal opiate overdoses in Scotland. Any patient deemed at risk of opiate overdose (or their representative/carer), including all those on Opiate Substitution Treatment, should be given instruction in overdose prevention, basic life support and how to inject naloxone. Training for staff and prescribers is available at naloxone.org.uk or LearnPro (Naloxone and Overdose Awareness). 
• Naloxone nasal spray 1.8mg (Nyxoid) may be recommended for individuals in secure environments, e.g. prisons, for whom an intramuscular preparation is not desirable or tolerated.
• Naloxone is a specific opiate antagonist used in the acute treatment of patients with respiratory and cardiovascular depression secondary to opiate poisoning. It is a short-acting compound (duration of action around 1 hour) which is given either intravenously or intramuscularly. The usual starting dose is 0.8-2mg (2-5 ampoules) and route and dose will depend on clinical circumstance. Intravenous administration produces rapid reversal which in addicts may precipitate aggression or withdrawal. GPs may therefore prefer the intramuscular route in a patient who is maintaining respiration. This route may also be used in an accident and emergency setting in patients who are threatening to self-discharge.
• Since naloxone is a pure competitive antagonist the dose required to reverse an opiate ingestion will depend upon the amount of opioid present. Initial doses of naloxone in seriously poisoned patients may be several milligrams. The dose should be administered slowly, monitoring respiratory and cardiovascular responses. Following administration monitoring of oxygenation (pulse oximetry), blood pressure and pulse at frequent intervals is required. Patients should be monitored closely for several hours, particularly if they have ingested oral opiates.
• Intravenous infusions of naloxone may be required in patients who have taken long-acting or slow release opiates. The initial infusion regimen should consist of an hourly dose of approximately 60% of the dose required initially to wake the patient. This should be given in a small volume of intravenous fluid, not in the 500ml bags recommended in older copies of the British National Formulary.