The standard form of methadone used in NHS Lothian is methadone 1mg/ml oral solution. Do not use higher concentrations or oral tablets.

Methadone has a long half-life (range from 14 to 72 hours) with mean of approximately 24 hours. It is frequently lethal in overdose or when given to opioid naive patients, or in those who have lost their tolerance to opioids.

Extra caution should be exercised when re-introducing methadone after a period of abstinence e.g. post intubation following an ITU admission.

Please consult with Drug Liaison Nurses or the PrePare Team if the patient is pregnant. See Useful phone numbers and contacts during working hours.

Cautions

Exercise extra caution when prescribing methadone in patients with:

• Respiratory disease
• Head injury – the Glasgow Coma Scale is not sensitive enough to assess opioid intoxication
• Renal Impairment
• Liver disease/hepatitis
• Co-existent alcohol dependence
• Overdose/decreased tolerance
• If receiving opioid analgesia or other sedating medications
• Interactions with other prescribed drug e.g. rifampicin used in the treatment of tuberculosis reduces methadone plasma concentration by 30-65%
• Pregnancy; unless indicated for emergency treatment of seizure activity please contact PrePare Team for advice. See Useful phone numbers and contacts during working hours.

If a methadone dose has been missed for more than three days, refer to section Missed doses and contact the Drug Liaison Nurses for dosing advice. If out of hours, refer to the Inpatient substance misuse pathway

Buprenorphine is a partial agonist, however it also acts as an antagonist in the presence of a competing agonists such as strong oral opioids or diamorphine (heroin). This will result in precipitated withdrawal or opiate blockade. Precipitated withdrawal is a rapid and intense onset of opioid withdrawal, which can be particularly unpleasant for the individual.

For this reason, buprenorphine is less sedating than methadone and is safer in overdose.

Buvidal is a long-acting injectable form of buprenorphine. It is available as weekly and monthly subcutaneous depot-type preparations and is initiated by Community Substance Use Team. It is important that Buvidal is continued throughout the patient’s hospital admission therefore a supply should be arranged via Pharmacy and/or Drug Liaison team.

Espranor is a freeze-dried buprenorphine wafer (oral lyophilisate) that disperses very rapidly on the tongue. It is indicated as a substitution treatment for opioid drug dependence.

Care must always be taken when titrating or re-titrating buprenorphine doses. As with methadone, extra caution should be taken if a buprenorphine dose has been omitted for more than three days and advice should be sought from the Drug Liaison team.

Do not routinely supply methadone/buprenorphine on discharge. There may be exceptional circumstances where this is appropriate such as an unexpected weekend discharge but this should only be considered on a case-by-case basis. If patients require a supply for discharge, the discharge prescription must be sent to pharmacy for dispensing.

1. Inform the community pharmacy of the last dose of methadone/buprenorphine administered in hospital as this will allow continuation of the community prescription if it is still valid.
2. Contact the patient’s GP or substance use service (SUS) prescriber to inform them of the discharge and confirm the dosage of methadone/buprenorphine prescribed.
3. Ensure the discharge letter is completed and authorised by a clinical pharmacist during normal working hours.
4. During normal working hours, contact the Drug Liaison Nurse or clinical pharmacy team for support with the discharge prescription and transfer of care.

This is particularly important for weekend or public holiday discharges (taking into consideration Saturday half day opening and Sunday closures for some community pharmacies).