There are 3 morphine alkaloids, and are as follows:
Morphine: C 17H 19O 3N; codeine: C 18H 21O 3N; thebaine: C 19H 21O 3N

Although all narcotic pain killers are based on the same opiate derivative, it is the Presence in morphine of three oxygen atoms, one of which belongs to a phenolic hydroxyl (solubility in bases from which carbon dioxide re-precipitates it; change of morphine (phenolic) into codeine, or methylmorphine, by methylation; the second, to a secondary alcohol group (absence of the phenolic character of codeine; esterification; oxidation into a ketone, codeinone VII); and the third, chemically inert, to an epoxydic cycle, that places these three in the morphine alkalide family.

Narcotic pain killers such as hydrocodone, follow as such; 4,5a-Epoxy-3-methoxy-17-methyl morphinan-6-one.

Never the less there are 3, and are, morphine, codeine, and thebaine, but all fall under the narcotic analgesic category. Hope this helped in any way.