Page:A manual of pharmacology and its applications to therapeutics and toxicology (1922).djvu/286

 mals. When both OH groups arc replaced by acids (heroin) the narcotic action is stronger than for codein, the tetanic action ia weaker than with morphin. The constitution of the morphin group of alkaloids is discussed by M. Freund, 1919.

Comparative Activity of the Two Groups. -- The alkaloids of both groups are more or less narcotic and convulsant. The essential differences are in the peripheral actions on all kinds of smooth muscle: Their contractions and tonus are stimulated by (he phenanthren group (morphin and its esters), and depressed by the isoquinolin group (papaverin, etc.). This applies to the intestines, bile ducts vas deferens, bronchioles and blood vessels. Macht, 1918, attributes the stimulation to the pyridin radical of the phenanthren group; the depression lo the benzyl radical of the isoquinolin group.

Convulsant-narcotic Series. -- In general, the narcotic actions on the brain, on the one hand, and the stimulant action on the cord and medulla on the other, are in inverse ratio; morphin being the most narcotic and least convulsant. and thebain the most convulsant and least narcotic; the other morphin esters and the isoquinolin alkaloids being intermediate. Claude Bernard arranged them in the order of: Morphin, codein, taKolin, papaverin, laudanosin, thcbain. Buergi, 1914, places them as: Morphin, papaverin, codein, narcotin, narcein, thebain.

Meconic Acid. This has no effect in the doses which would be administered in fpium. Larger doses produce narcosis, muscular tibrillation; medullary convulsions; (uarrbea; curure action (Barlh, IQ12).

Fapavtrin. -- Tliis is discussed in a sepiirntc section.

Narrolin. -- Tlie peripheral actions appear to be similar to papaverin, but weaker f*^, iQU)- Macht, IQ15, found, contrary to Straub, that it is quite toxic to the heart, tipintion and other functions.

S'arcfin, -- The peripheral actions resemble narcotin (PalÂ» 1014)-

Differences between Morphin and Opium ; Opium Alkaloid Mixtures.

^Wiilt the actions of opium are essentially tho^^e of its principal alka- loid, morphin, there are various diiierences, especially quantitative. These are due partly to the mechanical action of the gums and resins, ifeich delay absorption, and thus increase the local and diminish the ttatral actions. In the main, however, the differences are due to the pres- ence of the minor alkaloids, which modify the effects of morphin; for finiQar differences exist in mixtures of the alkaloids, natural (Pantopium) wwiifidal (Narcophin, Laudanons).

The precise differences between the actions of morphin, opium and the

Tiired alkaloids are still under dispute. The statements of different (and

lies of the same) obser\'ers are so contradictory that it is often

'de to judge them (Literature, E. Buergi, 1914).

mrd Therapeutic Advantages. â€” It is asserted that opium and the

- . uj mixtures, for a given degree of analgesic and cough -sedative action,

Qiisc less depression of respiration and less nausea; that their action,

'^ '-H slower, is more prolonged. It is also claimed that opium and

um are more efficient in checking diarrhea; while at the same time,

''â– \i staled that pantopium is not as constipating for normal individuals.

^ '-rr considering these actions in detail, it is necessary to describe the nature of

nercial products which have been largely used in the investigation?;. J^^v'pOB (Pantopium Hydrochloricum), N.N.R. â€” This consists of the isolated alka- imkof opium in their natural proporlionfi. It was introduced by Sahli. Discounting prompter absorption and makes it much more suitable for hypodermic injection, irfftacologic data on pantopium are reviewed by Barth, i9i2;Schwentncr, IQ12; TTiomas, 1913. Severe poisoning from 0.04 Gm. is reported by Voigt, 191 1. iclions are quoted by Seifert, Ncbenw-irk., 1915, p. 81.
 * ,Mft)r extravagant claims, it has the advantage that the absence of gums and resins