What's a good ontology for drug names? I have ...


A database with patient phenotypes in, stored as HPO terms
Genetic data in whatever format I need


I want ...


To store drug names in a way that won't make my life difficult
If it's feasible, to make them so that you could draw links between HPO terms, medications, genetic changes, and outcomes.  Note that I'm not actively trying to do that, but I don't want to exclude the possibility of it in the future


Ideally, I'd like those drug names in some kind of ontology, and even more ideally an ontology that's available on http://bioportal.bioontology.org

So - what's the best drug ontology to use in this case?

Update


  What relationships would this drug ontology describe? Structural similarity of the compounds? Affected pathways? How would they be linked? Do you want all drugs that can cause the same side effect linked, for instance? Or all drugs that can be used for the same disease? 
  Drugs by disease would be the most useful.  The information that would be most useful would be something like



Atenolol


Atenolol 25mg
Atenolol 50mg
Atenolol 100mg

Propanolol


Propanolol 10mg
Propanolol 40mg
Propanolol 80mg
...



In short, being able to get a list of dosages for a given drug.  It'd be extra-useful if I could also retrieve a set of drugs for a given condition, so in the above example to retrieve a list of beta blockers (Atenolol, Metoprolol, Nebivolol, ...)


  Have you looked at any of the various drug ontologies listed in bioportal.bioontology.org? Which ones have you discarded so we don't suggest the same ones? What were they missing that you need?



MDDB doesn't seem to be structured as above
Likewise The Drug Ontology
RxNorm seems to be the best available that I've seen
Since this question's been asked there's been a (what looks like a first useful?) release of Drug Ontology DRON. Perhaps worth checking again?