American Materia Medica, Therapeutics and Pharmacognosy

Codeine has a marked influence upon spasmodic cough. It is often given
to soothe irritable conditions of the air passages and to control persistent
annoying and exhausting cough.
Physiological Action of Opium and Morphine.
The action of opium, and of morphine and its narcotic salts, is much the
same. Opium is stimulant and narcotic, according to the dose and
susceptibility of the patient. Infants and old people are easily poisoned by
the drug, while those addicted to alcohol can take very large doses
without any bad effects; and those accustomed to the drug can take a
poisonous dose with impunity.
In the healthy adult a moderate dose of opium stimulates all the nervous
functions of the body, raises the spirits and excites intellectual action;
this gives way to a condition of placidity, freedom from care, and a state of
quiet enjoyment. In an hour or less, con-sciousness is lost in sleep,
which may continue for eight hours or longer. On waking there is
evidence of disturbance of the functions of the organism, such as nausea,
vomiting, headache, constipation and diminished secretion, except that
of the skin.
In a dose sufficient to cause death the period of excitement is short, while
the strength of the system rapidly gives way to drowsiness and apoplectic
sleep. There is stertorous breathing, dusky countenance, slow pulse,
nearly total insensibility, only responding slightly to violent agitation,
with confusion of the mind, and an inclination to continue in a comatose
state with increasing debility. After a few hours, six to twelve, according
to the dose and the resisting power of the patient, the face becomes pale,
the pulse from being full and strong becomes weak and thready, with
cold extremities, a cool and clammy skin, a slow gasping respiration; a
condition from which it is impossible to rouse the patient and death soon
follows.
The pulse is first slow from stimulation of the vasomotor nerve centers,
and becomes rapid as these become paralyzed. The pupil is first
contracted by stimulation of the oculo-motor nerves, and dilates as death
approaches and these become paralyzed. Death results from paralysis of
respiration.
With some individuals there appears to be an inherent and usually
Ellingwood’s American Materia Medica, Therapeutics and Pharmacognosy - Page 316