It's hard to know what the side effects are since it hasn't been tested in humans and is not in a form where it would be a useful drug. We've had plently of promising drugs turn out to have unexpected and sometimes devestating side effects when tested in humans.

It's fine, morphine is used as a 'standard' for opiate and other pain killer efficacy. So often that the term 'morphine equivalency' exists in medical documents.