Ethical drug and Medicinal drug

Ethical drug noun - A drug that is available only with written instructions from a doctor or dentist to a pharmacist.

Medicinal drug and ethical drug are semantically related. In some cases you can use "Medicinal drug" instead a noun phrase "Ethical drug".

Medicinal drug noun - (medicine) something that treats or prevents or alleviates the symptoms of disease.

Ethical drug and medicinal drug are semantically related. Sometimes you can replace phrase "Ethical drug" with "Medicinal drug", this phrases are similar.