Papaveretum is a mixture of opiates. It has a potent analgesic effect which is almost all due to the morphine it contains. The small amount of codeine it contains might produce a tiny increment of analgesia. Papaverine is not analgesic, and thebaine not a widely used drug. It is standardised by the addition of morphine to a mixture of opiates in the proportions found in opium to contain 50% morphine by dry weight.
The standard ampoule contains 1.1 ml, and thus the usual answer to "how much papaveretum is in that ampoule is wrong by 10%. The usual answer to "what is papaveretum?" "a drug ..." is wrong by a larger margin.
The mixture lacks any clinical benefit and the logic of its introduction and continued use is not apparent.