Therapeutic Handbook - GGC Prescribing

Continued from previous pageMethadone prescribing• For patients not on a methadone programme speak with specialist if patient is likely to be inhospital for > 7 days. If methadone is advised then table 2 outlines management for the first 3days.• Patients requiring > 100 mg of methadone should be monitored for prolongation of QT intervaland torsades to pointes.• Methadone has a long half-life (14 – 72 hours, mean about 24 hours). It is frequently lethal inoverdose and in appropriate maintenance dose (60 mg – 120 mg) when given to patients whohave lost their tolerance to opiates or opiate naïve patients.• If patient is newly commenced on methadone and requires doses > 60 mg/day seek specialistadvice (Appendix 6 for contact details, under ‘Drug Misuse’) before prescribing.• Stop if any signs of intoxication e.g. drowsiness, slurred speech or respiratory depression.May need to administer naloxone IV/IM. This is contraindicated in pregnancy, however in lifethreateningsituation use with caution at lowest possible dose.• On discharge do not supply methadone. Instead:- If discharge for short period (< 3 days) before return to hospital advise the patient to return toward for daily supervised dose.- For all other patients see full guideline on StaffNet for details. Ensure continued prescriptionand interim continuity of care are organised in advance of patient discharge. Also ensurepatient’s GP or Community Addiction Team prescriber and Community Pharmacy are awareof methadone dose and time of last dose given in hospital.• Advise patient to see GP whether or not methadone is prescribed by GP.Table 2 – Initial methadone oral doseDay1Methadone dose20 mg initially. Reassess 12 hours later and give further 10 mg dose only if withdrawaleffects are still evident (maximum total dose on day 1 is 30 mg)2 Same total dose as day 13 As aboveCentral Nervous SystemContinues on next pagePage 181