This section is from the book "Laboratory Manual Of Pharmacology", by A. D. Bush. Also available from Amazon: Laboratory manual of pharmacology.
Morphine (C17H19NO3 + H20) is an alkaloid of Opium. Opium is the dried juice of Papaver Somniferum, an Asiatic plant:
Central Nervous System. - The higher cortical centers are depressed, especially the centers of concentration, co-ordination, and summation. Receptive faculties are lowered, especially the apprehension of pain. Later, entire system is depressed, but spinal activity is primarily augmented.
Muscular system affected by overwhelming doses only.
Respiration. - Morphine slows respiration by centric action, and renders it shallower. Later it becomes periodically irregular, weaker, and fainter.
Heart not affected until late, when it becomes slowed.
Blood-pressure continues high until late. Facial vasodilatation.
Pupil is sharply contracted (centric) until death approaches; then it become:; widely dilated (from asphyxia).
Alimentary Canal. - Nausea is induced by centric action. Lessened peristalsis from local action on neurons.
Secretory glands inhibited somewhat, except the sweat-glands.
Metabolism. - Excretion of CO2 lessened. Increase of lactic acid in blood and urine. Disappearance of glycogen in liver.
Temperature slightly lowered, from depression of center.
Absorption is fairly rapid from mucosa and subcutaneous tissues.
Excretion takes place from parotids, stomach, and bowel.
Local Action. - None whatever.
Tolerance is readily acquired.
Lessened voluntary movements.
Lack of attention.
Somnolence, more or less deep.
Alternating obstinate constipation and diarrhea. Marasmus and cachexia. Cirrhosis of skin.
Deep, torpor-like sleep.
Respiration very slow.
Pulse slow and full, becoming thin, weak, and rapid. Pupils contracted. Mouth and throat dry. Face cyanosed. Respiratory failure.
Disorders of motor-nervous system. Marked mental and moral deterioration.
Morphine is used to allay cough (diminished reflexes), to check severe diarrheas, to induce sleep, and to relieve pain.
0.008 to 0.016 Gm.
The action of Codeine is similar to that of Morphine, though to a much less degree. Dose: 0.015 to 0.08 Gm.
Crimson = stimulation. Green = irritation. Violet = depression.