More than 200 people in the Bay are using methadone to treat an opioid dependency.
In April, the Bay of Plenty District Heath Board had 207 people using methadone to treat addiction to opioids, which often included an addiction to street methadone and other opiates such as codeine and morphine.
Health board chief executive Helen Mason said the average length of time a person used methadone, officially referred to as opioid substitution treatment (OST), was five-and-a half years.
The longest time a person had spent on the programme was 24 years.
Mrs Mason said OST also included comprehensive assessment of people's wider needs, focusing on physical, emotional and social needs.
"This includes practical support in finding housing and managing money. Many of this client group have poor physical health and need support to address dental care and other health issues.
"Therapeutically, there are a range of approaches depending on the person's needs. These include individual or group therapy programmes, advice on lifestyle, parenting support and regular reviews by their treating doctors and case manager."
Mount Maunganui GP Tony Farrell used to run a GP-based OST service until recent law changes saw patients transferred to care under the district health board.
Dr Farrell said methadone was a widely provided and effective medication for opioid dependency.
"We give people methadone not to get them high, but to stabilise the cycles of intoxication and withdrawal. If you take it, you don't feel high.
"The aim is to slowly withdraw over time."
Most people had a dose once daily, but others had to have it twice a day because they metabolised quickly.
The amount of time on the prescription varied.
Dr Farrell said he had a 67-year-old patient who had been on methadone for years and was working and doing well - others managed to get off it after just a few months.
"With methadone, it's so rewarding as a doctor to give that to someone who is looking tired and stressed. They start to look healthy again. It takes away the stress of having to go and find illicit drugs."
April O'Hanlon, clinical lead at Get Smart Tauranga Drug and Alcohol Services said OST allowed opioid-dependant people to function without going into withdrawal, and without drug intoxication.
"In simple terms, it replaces an illicit drug with a prescribed legal drug," she said.
"Opioid substitution therapy is used worldwide for the treatment of opioid dependence - since the 1960s. Opioid dependence is a complex, relapsing condition and OST is an effective treatment option.
OST is most effective when given for prolonged periods of time to allow individuals to make lifestyle changes and abstain/reduce from illicit drug use."
She said there were two approaches provided in New Zealand for people with opioid dependence - managed withdrawal and OST.
"Many people will resume illicit opioid use within six months of completing an opioid withdrawal and so it is important that other treatment options are offered.
"The success of opioid substitution treatment is well researched and it is effective in reducing illicit opioid/drug use and other drug related harms. The benefits are wide ranging from the individual level to a public health perspective."
Access to OST allowed people to significantly improve their physical and psychological health, relationships, social functioning, gain employment and see an overall improvement in their well-being.
"Other benefits include a reduction in injecting practices and the associated blood-born virus transmission, ie, hepatitis C and the reduction of substance related criminal activity."
Health board clinical director of mental health Sue Mackersey said methadone was prescribed on a controlled drug script that was sent to the pharmacy to dispense to the client.
The client may be observed to take the methadone in front of the pharmacist or the pharmacy will provide the client with the doses to take home, often referred to as takeaways.
The number of takeaways and observed doses differed per client depending on how stable a client was in their treatment.
"Clients who are in GP shared care treatment will have a greater proportion of their weekly methadone prescribed as takeaways than a client, who is considered unstable and needing close monitoring from the specialist service.
"There are a small number of clients who will have no takeaways."