Agonist and antagonist substitution

Methods of modifying behaivour - 

Methadone 

Agonist - chemical that binds to a post synaptic receptor and activates that receptor to produce a response. The imitate the action of another substance e.g. heroin. 

Methadone is an example of an agonsit drug and is used as part of the maintenece treatment. The main aim of giving methadone to addicts is that it will reduce the cravings for the inital drug and reduce any withdrawal symptoms that would normally be experienced when stopping an addiciton. For example when used to treat heroin, it gives the same effects as heroin but without the same 'high', therefore without this high it would be assumed that individuals stop the addicition, as they no longer feel as though they need or want the drug. 

National Institute for Health and Care Excellence (Nice) suggest than a dose of 10 - 40 mg of methadone each day, which can be increased by up to 10mg until no withdrawal symptoms can be seen. Methadone is given orally as a liquid so that it avoids any risks assiciated with needles if it was given by injection. This is important…