5 years old is very young to be diagnosing ADHD. It is also very young to be taking medication. There are therapies that are used with children that are used either with or without medication.
My first suggestion, though, if you haven't already done so, is to make sure that her diagnosis was made by a licensed psychologist with training and experience in treating children for these specific disorders. Pediatricians, social workers, and psychiatrists are not trained in diagnosis of psychological disorders.
Psychologists are not only trained in diagnosis and treatment, but usually are also knowledgeable about medications. Although psychologists can not yet prescribe medications, they usually work in conjunction with either the client's physician or psychiatrist, and often recommend medications.
If you've already gone this route, gotten testing, and are getting therapy, then I apologize for being redundant. But it is amazing how many social workers and/or pediatricians, however unqualified, give these diagnoses and prescribe medication that is unwarranted, while saying nothing about therapy/counseling.
That all being said, if you do have a bona fide comorbid diagnosis of ADHD and ODD in a 5 year old child, then I would get another opinion before medicating her.
But I also want to emphasize that ADHD and ODD are both difficult disorders to deal with. I have a friend who is going through the very same thing with her daughter, although her daughter is now a little older (but has always had these problems.) Her daughter started taking medication for her ADHD when she was in 3rd grade, I think. My friend is just now seeking therapy for a problem that started years ago and has had the chance to get much worse.
It's good that you're dealing with this sooner, rather than later. There are counseling and clinical psychologists that deal with these issues and I strongly encourage you to seek one out. Therapy is not only necessary for your daughter, but for the family, as well. Getting your daughter's anger and behavior under control means not only changing your daughter's thoughts and behaviors, but yours, your husbands, and siblings, if applicable. Parenting techniques are a part of this, too.
Good luck. The best advice I can give is for you not to go it alone. Get a good child psychologist trained and experienced in these areas, and make sure you're a "good fit."
Oh, and you also might consider nutritional therapy as well, particularly for the ADHD. Some of that hyperactivity can be controlled by diet. Also, an outlet for all that energy would help, as well as provide an outlet for her anger. My son had ADHD and I bought him a drum set, which was wonderful. It provided a good outlet for him and it didn't bother me at all.
Since having ODD is not conducive to team sports, you might try getting your daughter involved in something she can do on her own - playing an instrument, swimming, horseback riding, etc. Something physical.
Good luck! I'll say a prayer for you all.