How much time do you have? 😉 There's a lot to learn if you had the time, but one thing you could do to help you learn the top drugs is to break them up into their classes. Learn the drugs in your antihypertensive drug classes: ACE Inhibitors, Angiotensin Receptor Blockers (ARBs), diuretics, beta blockers, etc. Learn your dyslipidemia drug classes: HMG CoA Reductase Inhibitors ("statins"), Fibric Acid Derivatives ("fibrates"), bile acid sequestrants, etc. Learn your type 2 diabetes drugs, antibiotics, proton pump inhibitors (PPIs), etc. You'll learn that some drugs within classes have similar sounding names (ACE Inhibitors end with "-pril") which might help organize these drugs and help you learn about them better. Read the monographs or drug package inserts stuck on the bottles. Your pharmacist might not object to you keeping those to read in your spare time. It might be worthwile (although quite ambitious) to try to learn how some of these drugs work, what is known as their "mechanism of action", which most drugs within a particular class have in common. You can find that in the drug monographs/package inserts, or Facts & Comparisons. Once again, that might help you remember the drugs.
What I'm trying to say is that if you break up the top 200 into classes, it might make the task a little less daunting. If you can learn trade/generic names with their classes you'll have learned something you can use by the time you get to your therapeutics courses.
PS. If you want a top 200 list to study, you can PM me.