Hypoglycaemic and Hyperglycaemic is my least favourite example of the former.

Probably hypo/hyper several other things too, now you mention it. When we imported those prefixes from Greek we made a big mistake putting the stress somewhere other than the distinguishing vowel...

Also oral/aural.

Especially because when you need to say it, you (a) can't say it clearly, (b) through sod's law end up saying it to somebody who understands only the opposite word to the one which is true, (c) need help QUICKER than that.