I recently took the shelf. Don't bother with dosages and lengths of regimens (PreTest is a bad offender in this because it will have 5 answer choices with different lengths of regimens, which is useless info). You should however know what are the first, second, third line treatments for most common conditions (DM, HTN, CHF, infections), and also what you would give with people who have multiple comorbidities (ex. ACEIs with someone who is both diabetic and hypertensive).
I had only one question which required me to know "numbers" and it was different saline bags (0.1, 0.9, 3.0, etc). It was only one question and was an incredibly stupid one to throw in there.
The shelf was a lot of physical diagnosis and treatment, and some "next step in management" questions.