Personally, I wouldn't recommend selecting a career path only because of employability. Don't get me wrong, job security is important, but if you are going to hate the job, it's going to have a huge detrimental impact on your mental health regardless of pay and other benefits. I'm talking from personal experience here - spent 10 years of my life on a career (finance/business ops in retail) which I hated, and which I had only chosen because I was told that's where I get the money. I did get the money, but I regret wasting so many years living the hell that I could have avoided if only I listened to myself, what I really wanted to do, who I really wanted to be.
Besides, if you become a really good specialist you are always going to be in demand regardless of the career/industry you choose.
Now since I'm an engineer, who went through it all and who currently works in a large corporation, occasionally hiring engineering graduates, I have to say that the job is fun (if you like the technicality of it that is), I feel quite secure about my future (I pretty much can find myself a job within a week or two in any part of the UK), and the pay is decent.
I've no clue about pharmacy so I can't say much here, besides the fact that I noticed the pharmacies in my area struggle to find enough pharmacists and they get to share a few of them between the many pharmacies around this place (Boots, Lloyds, etc.). To me that means there is more demand then supply at least from what I can see. Again, I have no idea of the real picture so can't compare to engineering.
Regarding the professional growth it feels engineering can be more supporting from the wide range of potential career opportunities. There is space for research and development if you're into that, you can pursue a career in academia, you can grow in "ranks" and climb the corporate ladder either deepening your technical skills or going into managerial roles, from where you could continue growing into managing more people, teams, and potentially business operations if that's what you want. I find engineering to be a quite an empowering career, but a lot of the success depends on the individual.
I hope that helps a little.