Question 3: What are the guidelines for initial dosing?

Answer:

Australia
Determining the initial dosing of methadone is guided by a number of factors that include the severity of the patient’s opioid dependence, drug use history, and the results of the medical examination and urine test. Prescribing the first dose of methadone requires consideration of whether the patient is using other central nervous system depressants and their hepatic functioning. An initial dose of 20 mg for a 70 kg patient is “presumed to be safe.” Practitioners are warned to exercise “caution” for starting doses above 30 mg and to exercise “extreme care” when the initial dose exceeds 40 mg. (Clinical guidelines and procedures for the use of methadone in the maintenance treatment of opioid dependence, http://health.gov.au/internet/publications/publishing.nsf/Content/drugtreat-pubs-meth-toc).

Canada
Patients are given a specific first dose of methadone, based on assessment outcomes, and observed for a period of time to determine reaction and toxicity. Guidelines require initial low doses (10-30 mg for first 3 days) for those at normal risk, and lower doses (10-20 mg) for those who have a higher risk for methadone toxicity, including those who use depressants, are alcohol dependent, are 60 years or older, or have respiratory problems.

United Kingdom
Concern for risk of overdose requires practitioners to start initial dosing between 10 and 30 mg daily. Patients using sedatives, including alcohol, are limited to 20 mg a day. Increases should be limited to between 5 to 10 mg a day with a maximum of 30 mg a week for the first two weeks. Doses should then be titrated upwards to optimal levels, usually between 60 and 120 mg. (Royal College of General Practitioners Guidance for the use of substitute prescribing in the treatment of opioid dependence in primary care, http://www.rcgp.org.uk/clinical-and-research/clinicalresources/~/media/Files/
CIRC/RCGP%20Guidance%20%20for%20the%20use%20of%20Substitute
%20Prescribing%20in%20the%20Treatment%20of%20Opioid%20Dependence
%20in%20Primary%20Care%20-2011.ashx) (2.4MB).

United States
The acceptable initial dose for methadone treatment is 30 mg daily, unless a reason for a higher dose can be evidenced, which could increase the initial dose to no more than 40 mg a day. Based on the judgment of the program physician and careful observation of the patient, dosing can go up to 60 mg a day prior to stabilization (http://dpt.samhsa.gov/pdf/draft_accred_guidelines.pdf) (267KB).