I may be wrong but I don’t think opiates were available back then. A “surgeon” at Yorktown told me anesthesia was alcohol and a leather strap to bite on.
“Opium’s history in the United States is as old as the nation itself. During the American Revolution, the Continental and British armies used opium to treat sick and wounded soldiers. Benjamin Franklin took opium late in life to cope with severe pain from a bladder stone. A doctor gave laudanum, a tincture of opium mixed with alcohol, to Alexander Hamilton after his fatal duel with Aaron Burr.”