The one we use in my pharmacology class is horrible. It only gives one extremely vague sample drug profile for each general category/class... so I've been scouring over the internet to find information on all the other drugs.
Try bookmarking and using www.drugs.com They have profiles for almost all the drugs on the market. You can search for drugs alphabetically by generic or brand name, or by medical conditions and diseases if you need lists of medications used in certain diseases. They also have information on each drug separated into patient information and professional information. A lot of the information for professionals is the same as what is in the PDR. They will also provide links to other internet sources about some of the drugs. Some drug companies have websites set up for specific drugs in order to provide consumer information to patients that use them, particularly if the drug is a top seller or newly released and being advertised heavily. As an example, when I was looking for information a few years ago on Tamiflu when it was first released to the public, I ran across the phamaceutical company's website on it. Learned all about the signs and symptoms of the flu and what Tamiflu did. I was writing a care plan for a nursing home I was working in at the time and got a lot of information off that site. Also, there's a lot on diabetes at the Insulin manufacture's sites. Use www.drugstore.com/pharmacy/drugchecker for information on interactions between medications.
I have found that Mosby's Pharmacology Memory NoteCards is very helpful. It's amazing b/c I am a visual learner, and if there are two treatments for a specific disease, there may be a cowboy with two pistols saying that there are two treatments/drugs for it. It's very helpful. Another one that is very good is Davis Drug Guide for Nurses. They are great. Good luck.