I am a pharmacist who is currently in medical school. I have taken both the PCAT and the MCAT. The PCAT was nowhere near the level of difficulty as the MCAT. Not even in the same ballpark. My MCAT score was marginal (somewhere in the 60s percentile), but good enough to get me into medical school in the US with my other credentials. I got a 96% on the PCAT, and didn't study half as long. And I hadn't even taken organic chemistry when I took it. Having taken the PCAT, the NAPLEX (pharmacy license exam), the MCAT, and 2 years worth of medical school exams, the MCAT is still the most difficult exam I have taken to date. (Yes, that means med school exams are not as difficult as the MCAT, the hardest part is getting in!). I can't say much for similarities between them. But you have to know the MCAT material better than the PCAT material because the questions are more complex and (it felt like) less time to answer them. I felt rushed the whole time, and my brain was fried when I was done. I felt as though all my thinking ability was exhausted. I felt nothing close to this for the PCAT, just my honest assessment.