Chemical and Pharmacological Aspects of Opium Alkaloids
Papaveretum or Opium Concentration is a standard preparation of the hydrochlorides of the opium alkaloids containing 47.5–52.5 percent anhydrous morphine, 2.5–5 percent of codeine, 16–22 percent noscopine (narcotine), and 2.5–7.0 percent papaverine. The first group (e.g., morphine) consists of alkaloids which have a phenanthrene nucleus. Those of the Papaverine group have a benzylisoquinoline structure. Some of the less important opium alkaloids (e.g., protopine and hydrocotarnine) are of different structural types. Bentley, K. W. stated that the alkaloids of the morphine group form a subgroup of the isoquinoline alkaloids being derived in nature from the bases of the laudanosine series by oxidative processes. Their pharmacological and chemical properties are sufficiently distinct. Morphine has a synergistic effect with other respiratory depressants such as other opiates, barbiturates, general anesthetics, and alcohol. The depressant effects of some opioids may themselves be exaggerated by the phenothiazines, monoamine oxidase inhibitors, and tricyclic antidepressants.