Schedule 2 & 3 The drugs in these schedules can be prescribed and therefore legally possessed and supplied by pharmacists and doctors. It is an offence contrary to the 1971 Act to possess any drug belonging to Schedule 2 or 3 without prescription or lawful authority. Examples of schedule 2 drugs are methadone and diamorphine (heroin). Schedule 3 drugs include subutex and most of the barbiturate family.
Schedule 4
Schedule 4 was divided into two parts by the 2001 Regulations ,
Schedule 4(i) controls most of the benzodiazepines. These drugs can only be lawfully possessed under prescription. Otherwise, possession is an offence under the 1971 Act.
Schedule 4(ii) drugs can be possessed as long as they are clearly for personal use. Drugs in this schedule can also be imported or exported for personal use where a person himself carries out that importation or exportation. Examples include steroids.
Schedule 5 Schedule 5 drugs are sold over the counter and can be legally possessed without a prescription (release.org.uk). Examples include, Lomotil (an antidiarrheal medication) Lyrica (used to treat muscle pain) Robitussin (used to treat coughing)