What is the classification of codeine if it is greater than 1.8 grams per 100 ml?

Codeine is classified based on its concentration in combination medications. When codeine is present in a concentration greater than 1.8 grams per 100 ml (or 90 mg per dosage unit), it is classified as a Schedule II controlled substance. This is because substances in Schedule II are recognized as having a high potential for abuse, which can lead to severe psychological or physical dependence.

In this context, when the concentration exceeds the specified limit, it indicates a higher potential for misuse, which is why it is categorized as Schedule II. This regulation is part of the effort to manage and control the distribution of drugs that have a significant risk of abuse and dependency.

Conversely, lower doses of codeine or those combined with other medications can fall into Schedule III or Schedule V, where the potential for abuse is considered to be lower. Substances not classified as controlled at all pose no risks associated with abuse or dependency, and thus would not involve the same regulatory scrutiny.