By Oxford Dictionary standards, a drug is defined as "a medicine or other substance which has a physiological effect when ingested or otherwise introduced into the body.” That physiological effect is not a constant. There may be similarities in the effects and symptoms of a drug between people but there is no exact equivalence.
As prescribed, the use of prescription drugs can be very beneficial. Malevolently misused, prescription drugs become treacherous.
The use of synthetic drugs is beyond treacherous. Those who happen to survive are a bird escaped from stones, at best, unscathed.