As someone who holds their first degree in politics, you should know that the job market is really competitive and if you want to be working in the international sector you frequently need postgraduate education in addition to your first degree. So, if you are willing to go through that much additional education then switching to politics in your studies could be worth it.
However, something else that may interest you is merging pharmacy and politics. There are a lot of job routes that could benefit from your initial pharmacy degree, including but not limited to: public health research and/or policy, getting involved in medical law, or working as a pharmacist for disadvantaged populations (either globally or at home).
Since you have completed half of your pharmacy degree, I would suggest sticking it out and then pursuing a politics/policy based Master's course. Your first degree will set you apart from other common applicants, which could work to your advantage, and again the intersection between health and politics is a sector that is quite employable. If you hate pharmacy so much that you want to cast it off completely, then this may not be the route for you. But as someone who firsthand has compared the benefits of politics and international relations as a broad degree versus specializing, you would benefit more from the latter.