Are you a Lexi-comp subscriber? I am using Lexi-comp on my iPhone and a colleague also recently shared that she finds it the most comprehensive drug information source available today. I fully agree.
If you are just looking for drug information and drug interaction, the best value package I can think of is the Lexidrugs and Lexi-interact at $115 per year. If you subscribe for 2 years, you get a third year FREE! They have apps for iOS and Android.
Oh yeah, do me a favour and if you get any of the Lexi-comp mobile apps packages , please put my email email@example.com as the referrer – thanks!