Methadone titration in opioid-resistant cancer pain.
OBJECTIVE
To assess the use of methadone in patients with cancer pain who fail to respond to increasing doses of other opioids or experience intolerable side-effects from them.


METHODS
Inpatients of a specialist palliative care unit were titrated onto oral methadone. The dose was calculated as 10% of the previous morphine equivalent dose, up to maximum of 40 mg, given every 3 h as required for analgesia. When daily requirements were stable it was divided into two regular doses. Pain was assessed on a five-point verbal rating score (VRS): a good response was defined as a fall in VRS of two points or more. Results are expressed as median (range).


RESULTS
Thirty-three patients (13 men, 20 women, age 61 (34-91) years), 26 with inadequate analgesia and seven with intolerable opioid related side-effects, were converted to methadone from diamorphine (12), morphine (19) or fentanyl (two). Morphine equivalent dose was 480 (20-1200) mg/day prior to titration. Pain was neuropathic (11), nociceptive (three) or mixed (19). Stabilisation on methadone was complete in 3 (2-18) days in 29 (88%) patients at 80 (20-360) mg/day. Twenty-six (78%) had a good response. Four (12%) patients were withdrawn during titration (three entered terminal phase, one failed to respond). During follow-up 15 (45%) required alteration of methadone dose. Twenty-three (70%) patients were discharged home at 12 (4-26) days. In all cases the stable dose of methadone was less than the previous morphine equivalent, and there was a weak correlation between them.


CONCLUSIONS
This method of methadone titration often results in improved pain control in patients with morphine resistance or intolerance. It requires careful titration in a specialist inpatient unit as there is no reliable formula for dose equivalence.
Scholes
C F
CF
Mount Vernon Hospital, Middlesex, UK.
Gonty
N
N
Trotman
I F
IF
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004351:Drug Resistance; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage*; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage; D009369:Neoplasms / Q000150:complications*; D010146:Pain / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement; D013810:Therapeutic Equivalency
D000701:Analgesics, Opioid; D009020:Morphine; D008691:Methadone