Why does almost every drug that causes dependence have this "-ine" suffix?

I noticed that many drugs that cause dependence have the suffix word "-ine". For example:
[Caffeine](https://en.wikipedia.org/wiki/Caffeine), [nicotine](https://en.wikipedia.org/wiki/Nicotine), [benzodiazepine](https://en.wikipedia.org/wiki/Benzodiazepine), [methamphetamine](https://en.wikipedia.org/wiki/Methamphetamine), [cocaine](https://en.wikipedia.org/wiki/Cocaine), and [morphine](https://en.wikipedia.org/wiki/Morphine).


My questions:


1. Why do many of these drugs that cause dependence have the word "-ine" in them?
2. What does "-ine" mean in a chemical?




The suffix "-ine" is not necessarily a bad thing causing dependence, proline is just an amino acid and chlorine is a gas. So there must be another reason!


As per the Elsevier's Dictionary of Chemetymology



> 
> -in(e): ultimately derived from -inus (Latin suffix meaning belonging to or being similar to)
> 
> 
> 


One can then immediately guess the ancient organic names of natural products, with a little knowledge of plant names. What is the botanical name of tobacco? *Nicotiana tabacum*, so a chemist or whoever extracted nicotine named it after deriving from tobacco plant.


The word coffee and hence caffeine are derived from Arabic. Its botanical name is *Coffea arabica* so one can guess that caffeine was derived from this plant.


Note the halogens form an exception and plenty of other common organic chemistry names in your list. Not all natural products are named after plants, it just could be a fictitious deity like *morpheus*. Get hold of a good dictionary and look up the word origins of each.


**Addedndum related to the comments:** This is not the reason that "-ine" was chosen to indicate nitrogen in medicines. The suffix "-ine" has a wider meaning. As stated, fluorine, bromine, iodine etc. have no nitrogen or compounds such as phosphine, arsine have no nitrogen at all. If you have access to the unabridged Oxford dictionary (>20 volumes) they have full page on "-ine" and the original meaning of "-ine" is derived from, related to, therefore amine is from "ammonia" and "-ine". Div*ine* is belonging to or related to God. In short, "-ine" is well beyond chemistry.


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