When developing and testing a new medication/drug, how do they know what the “right” dosage should be? What do they use as a starting point to determine safe clinical trials?

Question

Also, for treatments that require multiple doses over a period of time (i.e. the Hep B series, or other treatments that require several visits over a period of time), how do they know how far apart the doses should be?

In: 1

Answer 1

Testing in mice and occasionally monkeys. Then they use the data there to extrapolate a range of dosages per kg of body weight, and move on to human testing. They’ll test dosages in that range through human trials to see which one has the most effectiveness with the least severe side effects.