We do not need the European Medicines Agency.
We use the EMA for approving and licensing medicines.
Result: Bad
While the Medicines Agency is currently moving away from London, the UK will have difficulty approving and licensing medicines.
We currently work with other EU countries to share this work, as it's cheaper than everyone duplicating this work.
It's estimated that we the pay a fifth of whats required for an agency like the EMA.
We could copy what the EMA licenses, but we won't be involved in that process.
And we do have the "Medicines & Healthcare products Regulatory Agency" (MHRA), who are able to approve medicines - but they are severely underfunded, will need to hire people for highly technical roles, and they will be under increased pressure from lobbying.
If you disagree, or would like to add more details, please let me know.
You can suggest a reason for leaving the EU, or look at the other reasons.