American Materia Medica, Therapeutics and Pharmacognosy

This agent is so convenient and produces such immediate effects that it
is often used by the indolent, careless physician, when other agents
would produce better after results, and would more speedily promote a
permanent cure. It is, therefore, proper to caution the young physician,
against depending, upon it to too great an extent, and to urge him to
study well all other agents acting synergistically, so that when his
knowledge of the other agents permits him to choose between them he
will prefer them. He may thus be able to select an agent with a single
direct influence, where, with the administration of this, he has
undesirable side influences to overcome in addition to the treatment of
the other conditions.
Administration—Opium may be administered by the mouth, by the rectum
or vagina, by the hypodermic injection of its alkaloids, by application to a
portion of the surface of the body after removal of the cuticle, by
inhalation or by insufflation.
Where there is a temporarily apparent contraindication for its use, the
aqueous extract or the deodorized tincture (aqueous) or other aqueous
preparations, may be used, as water does not dissolve the narcotine,
which is believed to be the irritating and depressing principle of the
alkaloids.
Or it may be given in conjunction with some agent which will overcome
the antagonizing conditions. The acidity of the stomach may be
neutralized by an agreeable alkaline aperient. The inactive secretions
may be partially reestablished by pilocarpine or jaborandi, or the bromides
may be given in conjunction to soothe the nervous system, or ergot to
unload the brain of an excess of blood.
The hypodermic use of morphine is demanded and is justifiable where
great pain is present. In these cases the size of the dose must be
determined by the circumstances. Its influence is prompt and
satisfactory.
This method is preferable because the chemical influences of the gastric
secretions upon the salt are avoided.
Veterinarians find it necessary to always administer morphine in this
manner, as often no desirable effects are produced if brought in contact
with the stomach and intestinal secretions.
Ellingwood’s American Materia Medica, Therapeutics and Pharmacognosy - Page 318