After 150 years of using morphine as a pain killer, the U.S. military has come up with substitutes that do the job better, and with none of morphine's side effects. The methods use better sensors, which enable identifying the precise nerve, that is sending the pain signal to the brain, and just neutralize that nerve. Most other pain killers act on the brain, which has harmful short, and long term, side effects. The most common pain killer, especially in combat, is morphine. Prolonged use of morphine causes the patient to develop tolerance for the drug, and larger doses are required to kill the pain. Addiction to opiates is also common with too much exposure to morphine.
The new methods, which use drugs or electrical signals (to scramble, and thus neutralize, pain signals headed for the brain) do not create tolerance or addiction, and are much more effective (as in not making the patient drowsy.) One problem with the new methods is that they are not as portable and convenient as morphine. But that is changing as the new technology becomes smaller, cheaper and easier to apply.
Morphine was the side effect of the industrial revolution (chemistry division), when it was discovered how to refine opium (an ancient drug obtained by scraping sap off poppy plants) into more powerful drugs. The two most famous of these were morphine and heroin.