Opioid Substitution Therapy – Basic Concepts and Principles Various terminologies have been used to describe the clinical practice of maintaining opioid dependent drug users on opioid medicines over a long period of time. These include–oral substitution treatment, opioid substitution treatment, oral substitution–buprenorphine, medication assisted treatment, buprenorphine maintenance treatment, methadone maintenance treatment, etc. All these terminologies describe the same practice. Under the National AIDS Control Programme, the term ‘Opioid Substitution Therapy’ (OST) is currently in use. OST is a process in which opioid-dependent injecting drug users are provided with long acting opioid agonist medications for a long period of time under medical supervision along with psycho-social interventions. Short term treatment of opioid dependence lasting for a couple of weeks called ‘detoxification’ which involves management of acute withdrawals alone, is associated with very high rates of relapse. Long term treatment is hence necessary for opioid dependence. OST is one such long-term treatment option. The lives of IDUs revolve around illicit opioid use. Most of their day is spent in procuring the drugs, using them and/or recovering from the effects of the drugs. Withdrawals and craving associated with opioid use compel them to consume opioids repeatedly. As the opioid drugs usually have short-term effects, the drug using population needs to inject them multiple times throughout the day. As a result, they are not able to concentrate on other aspects of their life, including their work, family and social roles/responsibilities. They are also forced to indulge in illicit activities to finance their drug use. OST addresses a number of such issues faced by the IDU clients: y the opioid medicines used for OST relieve drug-related withdrawals and craving and do not lead (when used in appropriate doses) to acute intoxication (which is seen with use of illicit opioids). Thus, the client is maintained in a state which produces neither intoxication nor withdrawals, nor craving. Due to this, the client does not need to use opioids to produce relief of withdrawals or craving. y As compared to the illicit opioids that act quickly and for a short period of time, opioid medicines used for OST act slowly and for a long period of time (for at least 24 hours). As a result, the client does not have to spend time on procuring or using opioids frequently in a given day and can focus on other important activities like occupational and family responsibilities. y The illicit opioids used by the clients are taken by routes that are potentially harmful. Many harmful effects faced by IDUs are due to the injecting route of administration. On the other hand, opioid medicines used for OST are administrated orally or sublingually, which is a much safer route. This saves the client from incurring harmful effects of opioid use. y As the IDUs procure the opioids mostly through illegal channels, they are often not aware of the purity of the opioid product they inject. This is especially true for heroin and its impure form, smack. The purity of street heroin varies across different time periods as well as across the drug suppliers. This may result in life-threatening overdose situations if the heroin is purer than usual. On the other hand, the potency and purity of opioid medicines used for OST is known; this helps in averting overdose situations. 20 Opioid Substitution Therapy under National AIDS Control Programme y As the street opioid drugs are costly, IDUs often resort to illegal activities to finance their drug use. However, as the opioid medicines used for OST are available in government supported centers/ hospitals free of cost, the client does not have to resort to illegal means. This helps in reducing legal complications faced by the clients and also reduces instances of petty crimes like thefts, etc. in the society. y During the illicit drug use phase, IDUs are often branded as anti-social or criminal by the families and the society. When on OST, such IDUs are seen as sufferers and ‘patients’. This renewed status helps the clients to seek help for other problems as well and makes them amenable for other help that can be provided.