It is easy to be an armchair expert, but I saw that this is not a viable idea: almost nobody would pay for it, for 99% of the cases patients and doctors already know the medication that is good enough and good for them (ibuprofen for me, acetaminophen for my friend because Ibuprofen upsets her stomach etc). And remaining 1% will most likely require serious medical attention, not just rando site. Let alone the fact that this is borderline dispensing medical advice which is a highly regulated activity!
One way to look for a similar business is examine.com (disclosure: I do not use them but read their write ups and articles about them on indie hackers-like sites and podcasts). It is a site that gives information about supplements. The supplement landscape is much more wide than that of painkillers, they are hard to compare, and supplements are usually chosen by consumers themselves, and supplement information is unlikely to be treated as a medical advice.