F38 Injection drug use and harm reduction


According to the World Drug Report 2017, an estimated quarter of a billion people, or around 5 per cent of the global adult population, used drugs at least once in 2015. Some 29.5 million of these drug users, or 0.6 per cent of the global adult population, suffered from drug use disorders.[1] People who use drugs, especially people who inject drugs (PWID), are isolated and often deny means to protect themselves from HIV, hepatitis C virus (HCV), tuberculosis and other infectious diseases. In many countries, availability of and access to scientific evidence-based intervention for treatment of drug use related disorders remains limited. It has been estimated that 1.6 million of PWID are living with HIV (prevalence 13.1%) while 1.3 million are infected with both HCV and HIV.[1]

In Hong Kong, the Central Registry of Drug Abuse (CRDA) maintained by the Government’s Narcotics Division has been tracking the drug use problem since 1972. As of 2016, the most common method of taking heroin among reported users was fume inhaling (59.1%), followed by injection (39.2%), with the percentage of injectors among all drug users showing a decline from 32.8% in 2007 to 20.1% in 2016.[2] The reported number of HIV infections associated with injecting drug use decreased from a peak of 58 cases in 2006 to a low level of an average of 8 cases per year in the 5-year period between 2013 and 2017. Incident cases of reported HIV infection attributable to injecting drug use accounted for more than 10% of all HIV diagnoses in previous decade falling to an average of 1.2% in recent 5 years. The point HIV prevalence of DH Methadone Clinic attendees as at end-2017 was 0.42%, as estimated from data collected through the Methadone Universal HIV Antibody (Urine) Testing Programme.

Despite a low HIV prevalence among PWID recorded in Hong Kong, the potential risk of HIV outbreaks among PWID cannot be overlooked. Needle sharing behaviour among PWID is a major route of HIV transmission in this sub-population. The rate of sharing injection equipment in the past 1 month remained particularly high at 18% among PWID, according to a local behavioural risk factor survey conducted in 2017.[3] Another community-based behavioural risk factor survey revealed that the injection rate among men who have sex with men (MSM) was 4.2%, of which a high proportion (44%) reported to have shared needles in the past 6 months.[4] Interventions to limit further transmission by harm reduction strategies, proactive outreach HIV testing services, early referral and prescribing antiretrovirals are still the cornerstones to eliminate HIV among this at-risk population. In this chapter, we focus on opiod substitution therapy (OST) and related activities and their implementation in Hong Kong and other regions.

Opioid Substitution Therapy (OST) in context of harm reduction

OST and other evidence-informed forms of drug dependence treatment curb drug use, reduce vulnerability to infectious diseases and improve uptake of health and social services; while needle and syringe programmes (NSPs) reduce the spread of HIV and other bloodborne viruses. Methadone is the most commonly used compound for OST. Naloxone is an effective treatment for opioid drug overdoses and saves lives. Treatments for HIV, HCV and tuberculosis greatly reduce morbidity and mortality. United Nations Office on Drug and Crime (UNODC), WHO and UNAIDS recommended using these services within a comprehensive package of health interventions.

Harm reduction refers to “policies, programmes and practices that aim to reduce the harms associated with the use of psychoactive drugs in people unable or unwilling to stop. The defining features are the focus on the prevention of harm, rather than on the prevention of drug use itself, and the focus on people who continue to use drugs“.[5] The principles of harm reduction can be readily applied to the management of patients suffering from substance abuse disorders. One commonly-quoted example involved the use of OST for users of heroin or prescription opioids. It involves offering a legal and safer alternative, for example methadone or buprenorphine, to these patients in order to control their craving and thus reduce the risk of relapse as well as the various morbidity and mortality risks from illicit self-administration.

Methadone Treatment Programme of Hong Kong

Objectives and activities

Methadone treatment programme (MTP) was formally launched in Hong Kong in 1976. Originally conceived as an anticrime initiative, it has now become an integral part of the Government’s overall anti-drug policy and has contributed to the control of HIV in Hong Kong. Its major objectives are, to:

  1. provide a readily accessible, legal, medically safe, and effective alternative to opiates and drug use;
  2. reduce the harmful consequences associated with drug use and the sharing of contaminated needles and syringes by providing an oral substitute, thereby preventing the spread of the HIV and other blood-borne diseases, such as viral hepatitis and tetanus;
  3. reduce crime by eliminating the financial burden of making daily purchases of illicit drugs and help stabilise the lives of drug users;
  4. enable drug users to live normal and productive lives and to continue to contribute to society.

Currently, MTP is delivered by the Department of Health (DH) through a network of 19 outpatient methadone clinics located in different districts of Hong Kong.[Box 38.1] Both methadone maintenance and methadone detoxification programmes are available. Clients enrolled in MTP may choose to be maintained on a daily dose of methadone, or to be detoxified through gradual tapering of methadone dosage according to their needs.

Box 38.1. Distribution of methadone clinics in the territory of Hong Kong

Box 38.1. Distribution of methadone clinics in the territory of Hong Kong

MTP means more than prescription and dispensing of methadone. Every client under the programme is clinically assessed by medical doctors at admission and subsequent follow-ups. Besides managing the underlying substance abuse disorders, various health promotion and harm reduction activities are conducted, including:

  1. Screening for communicable diseases including Hepatitis B, C and HIV;
  2. Hepatitis B, tetanus and seasonal influenza vaccinations;
  3. Health education on smoking cessation and alcohol misuse;
  4. Safer sex education and distribution of free condoms;
  5. Referrals to other health services (e.g. substance abuse clinics) for medical comorbidities or substance abuse disorders;
  6. Education and counselling on the harm of drug use and needle-sharing;
  7. Counselling and group counselling activities by social workers and peer counsellors.

Providing care to HIV-positive clients

Under the Methadone Universal HIV Antibody (Urine) Testing Programme, every client registered with MTP undergoes voluntary urine screening for HIV at admission and annually afterwards. The coverage of this programme is around 60-70% in recent years.

A methadone user found HIV-positive is first counselled and assessed by medical doctor and social worker in the methadone clinic and referred for HIV care, for example, at the Integrated Treatment Centre of Department of Health for further management. The client will be continuously supported and followed up by medical doctors and social workers at the methadone clinics. Algorithm 38 describes the management of clients under the MTP.

Management of intravenous drug use

Different strategies are implemented under MTP to reduce the harm of needle use among its clients. A detailed assessment of needle use history and practice of needle-sharing is conducted for each client during admission. Counselling and education on the risks are provided for those have a positive history. Clients are regularly advised to avoid re-use of needle and needle sharing and encouraged to quit their needle use. Their conditions are reviewed at subsequent follow-ups.

Outcome and key factors of effectiveness

Reviews conducted over the years have consistently commended MTP for its effectiveness in reducing intravenous drug use, preventing crimes and enabling its clients to lead normal and productive lives.

Effectiveness of MTP is thought to be due to a number of its features[Box 38.2] and has been affirmed by various international organisations and institutions including the World Health Organization, the Joint United Nations Programme on HIV/AIDS and the United Nations Office on Drugs and Crime.

Box 38.2. Features of the Methadone Treatment Programme in Hong Kong.

Low threshold of participation

  • No prior referral or appointment is required.
High affordability

  • Eligible clients are required to pay 1 Hong Kong Dollar (about 0.13 US dollars) per attendance at methadone clinic (23 Hong Kong Dollars for non-residents).
High availability and accessibility

  • The 19 methadone clinics are distributed throughout the territory. Most are located alongside other healthcare facilities (e.g. general outpatient clinics) and are easily accessible by public transport.
  • All methadone clinics open daily including Sundays and public holidays. Their service hours extend beyond office hours to facilitate those who are working full time. The clinics remained open when typhoon signal No.8 is hoisted or rainstorm black warning is issued.
  • Type Number of clinics Service hours
    Day 4 7:00 am to 10:00 pm
    Evening 10 6:00 pm to 10:00 pm
    Special hours 5 7:00 am to 3:00 pm
    1:00 pm to 8:00 pm
    3:00 pm to 10:00 pm

  • The confidentiality of the clients’ information is protected by the Dangerous Drug Ordinance (Chapter 134). Client records are kept strictly confidential.

Management of HIV infection in PWID

Illicit drug use plays an important role in HIV infection in terms of its role in disease transmission and increased risk of other co-morbidities, e.g. HCV infection and depression. The basis in the management of HIV infection in PWID does not differ from other HIV infected individuals. Highly active antiretroviral therapy (HAART) should be initiated upon HIV diagnosis if not contraindicated, with interval monitoring of treatment response and other conditions. HAART is generally effective in achieving good HIV virological suppression. Most HIV treatment failure in PWID is related to suboptimal drug adherence which can be due to intolerance, illicit drug use resulting in disruption of daily activities and other socioeconomic factors. It is important to discuss with each patient individually in order to identify their concerns and difficulties in remaining compliant to HAART. Successful HIV treatment in PWID requires a multidisciplinary approach, requiring input from different specialties, e.g. HIV physicians, psychiatrists, nursing counsellors and social workers.

When selecting antiretrovirals for HIV infected PWID, underlying health conditions and concomitant drug use should be considered. Methadone delays gastric emptying and is metabolised by the cytochrome P450 system. This leads to potential drug-drug interactions with some antiretrovirals. Efavirenz (EFV) and nevirapine (NVP) are CYP34A inducers which may lead to significant decrease in methadone level. Clinical symptoms of withdrawal usually appear 7 days after co-administration of methadone and ART. Dosage of methadone may need to be escalated to avoid withdrawal symptoms, usually by 5mg to 10mg increment daily until desirable effect is achieved. Use of protease inhibitors (PI), e.g. ritonavir-boosted lopinavir and ritonavir-boosted darunavir, could be associated with a decrease in methadone level. On the other hand, when these antiretrovirals are stopped, the dosage of methadone may need adjustment to avoid opioid toxicities.

Buprenorphine, a μ-opioid receptor partial agonist which has high affinity to opioid receptors, can also be used in opioid dependence. It is given sublingually and is sometimes co-formulated with naloxone. It has fewer drug interactions than methadone and is safe to use with most ART.

Levels of other recreational drugs, e.g. amphetamines, ecstasy, ketamine and gamma-hydroxybutyrate (GHB) may also be affected by antiretrovirals. There are reports of individuals developing overdose from recreational drugs after concomitant use of ritonavir-boosted protease inhibitors. Caution should be taken when prescribing antiretrovirals for individuals with history of recreational drug use.

Needle and syringe programmes (NSPs)

As one of the components of a comprehensive package, WHO suggests NSPs as one of the many measures to control the spread of HIV among PWID.[6] There are several components of NSPs as recommended by WHO and the rationales are as follows:-

  1. Provision of free needles – to reduce the number of injections with used needles;
  2. Provision of low dead-space syringes – to reduce the amount of remaining blood;
  3. Safe disposal for used syringes – by providing puncture-resistant containers (e.g. sharp box);
  4. Decriminalisation of carrying of needles and syringes – to reduce the resistance for PWID to take used needles for proper disposal; and
  5. Provision of injecting-related paraphernalia (e.g. alcohol swabs, sterile water, tourniquets) for safe and hygienic injection.

Similar to OST, NSPs aim to engage people who use drugs on a regular basis and to facilitate access to drug dependence treatment, to HIV treatment, care and support and to other important health and welfare services.

There is currently no programme distributing clean needles in Hong Kong. Under the Dangerous Drug Ordinance (Chapter 134) of the Law of Hong Kong, Section 36, “possession of pipe, equipment or apparatus fit and intended for smoking, inhalation, ingestion and injection of a dangerous drug” is illegal.[7] In Section 27, only registered medical practitioners and other specified persons are authorised to possess equipment for injection of dangerous drugs. Nevertheless PWID in Hong Kong are usually able to purchase needles from local pharmacies. NGOs also distribute “health kits” containing sterility materials such as alcohol swabs and bandages for safe and clean injection. Clips and sharp boxes are provided to cleaners for collecting used needles in places where PWID frequent, so that proper disposal of used syringes and safe handling is enhanced.

Situation of implementation of NSPs varies among countries. Possession of injecting equipment is decriminalised (legal) in Canada, Australia, some states of USA and some European countries. On the contrary, the largely punitive policy and legal environment such as detention and coercive treatment of people who use or are dependent on illicit drugs is currently still a dominant approach in some countries in the Asian region, such as Cambodia, Indonesia, Malaysia, Philippines, etc.[8] These practices continue to undermine PWID’s access to life-saving services.


Efforts to sustain linkage to and retention in HIV care for PWID who are newly diagnosed or are known to be infected with HIV should be sustained. It is equally important to maintain a high HIV testing rate for PWID both within and outside the network of MTP. Close monitoring of their health condition (HIV, viral hepatitis and other sexually transmitted infections) and injecting behaviour are continued.

Similar to many other long-standing programmes, MTP in Hong Kong is facing several challenges in recent years: (a) ageing client population which has resulted in the need for more considerations and support for their medical comorbidities and social needs. (b) Concerns from local communities – methadone clinics are often scrutinised by the public and the mass media for nuisance caused by gathering of drug users in their vicinities. From time to time, there are requests for closure or relocation of the clinics.

Algorithm 38. Management of clients under the Methadone Treatment Programme (MTP) in Hong Kong

Algorithm 38. Management of clients under the Methadone Treatment Programme (MTP) in Hong Kong


  1. United Nations Office on Drug and Crime (UNODC). World Drug Report 2017. Available from link
  2. Narcotics Division. Central Registry of Drug Abuse Sixty-sixth Report. Hong Kong: Hong Kong SAR Government, 2017. Available from link
  3. Special Preventive Programme. HIV and AIDS Response Indicator Survey 2016 (HARiS 2016). Hong Kong: Department of Health, 2017. Available from: link
  4. Special Preventive Programme. FACTSHEET: PriSM − HIV Prevalence and Risk behavioural Survey of Men who have sex with men in Hong Kong 2017. Hong Kong: Department of Health, 2018. Available from: link
  5. Harm Reduction International. What is harm reduction − a position statement from Harm Reduction International. Available from: link
  6. WHO, UNODC, UNAIDS technical guide for countries to set targets for universal access to HIV prevention, treatment and care for injecting drug users − 2012 revision. Geneva: WHO, 2012. Available from link
  7. Hong Kong e-Legislation. Cap 134 Dangerous Drugs Ordinance. Hong Kong: Bilingual Laws Information System. Available from link
  8. Harm reduction international. Community-based drug treatment models for people who use drugs, October 2015. Available from link