This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Croton Oil. - A fixed oil expressed from the seed of Croton Tig-Hum Linne (nat. ord. Euphorbiaceae).
India and Philippine Islands; cultivated.
A pale yellow or brownish-yellow, somewhat viscid, and slightly fluorescent liquid, having a slight fatty odor, and a mild, oily, afterwards acrid and burning taste; when applied to the skin, it produces rubefaction or a pustular eruption. Sp. gr., 0.940 to 0.960.
When fresh, in about 60 parts of Alcohol, the solubility increasing by age; feebly soluble in Ether, Chloroform, Carbon Bisulphide, and in fixed or volatile oils. The oil should be at least two years old; when fresh it is of no value.
The chief constituents are - (1) Several volatile acids (1 per cent. in all); these give the odor. Tiglinic Acid, C5H8O2, is the characteristic one; the others are Acetic, Isobutyric, Isovalerianic, Formic, Lauric, Myristic, Palmitic, Stearic, existing as glycerides. (2) Several fatty acids, both free and combined to form fats. (3) Crotonol, C18H28O4 a substance which is non-purgative, but is capable of causing cutaneous irritation.
Croton seeds are not official, but it is important to recognize them. They are 13 mm. long, 8 mm. broad, ovoid and bluntly oblong, covered with a brown shell, which on scraping becomes black. The kernel is white and oily. They yield 50 to 6o per cent. of Croton Oil. They are known from Castor. oil seeds, which are like them, by the fact that the Castor-oil seeds are bright, polished and mottled.
Croton oil is one of the most powerful irritants in the pharmacopoeia. A drop placed on the skin causes redness, burning pain, and quickly a crop of vesicles form (vesication); these rapidly become pustules (pustulation), and the surrounding subcutaneous tissue is red and cedematous. The pustules may be umbilicated, but differ from variolous pustules in that they vary greatly in their size.
Gastro-intestinal tract. - Very soon after a drop has been taken there is considerable griping and abdominal pain. In an hour or two the bowels are opened, and this may subsequently occur several times, the motions becoming, more and more fluid. The croton oil greatly aggravates the vascularity of the stomach and intestines, the mucous membrane of which becomes red, oedematous and angry-looking; there is a great increase of the intestinal secretion, but none of the bile. The drug produces, in fact, severe enteritis, and to a less extent gastritis. The motions may contain blood. These effects are all due to the local action of the croton oil. It is probable that the peristaltic movements are increased also; whether this is a result of the irritation, or of some action of the drug exerted after absorption, is not known. Croton oil applied to the skin may cause free purgation.
Croton oil was formerly employed externally as an irritant and a counter-irritant for inflamed joints, pleurisy, bronchitis, phthisis, etc.; but it is not often so used now, as the scars left after the suppuration are very unsightly, the application is too painful and the inflammation induced too severe. Corson's paint is a 5 to 15 per cent. solution of croton oil in ether, to which a small quantity of tincture of iodine is added to color it. A little croton oil spread over an area not exceeding that of a dime may be applied to set up suppuration in the scalp, and so destroy an inveterate patch of ringworm if it is wished to cure it quickly. The croton oil will certainly do this, but the resulting suppuration is so severe that the remedy should be used with care, and only when all others have failed. The liniment of the B. P., 15 per cent. of croton oil in equal parts of oil of cajuput and alcohol, well diluted, is occasionally employed to stimulate the skin in alopecia.
Croton oil should only be given in very obstinate constipation, not due to organic obstruction, and only one dose should be administered. Not more than one or two drops should be prescribed. Constipation due to lead poisoning and faecal impaction are sometimes suitable cases. Placed on the back of the tongue, it is, on account of its small bulk, a useful purgative for lunatics who refuse to take anything, and for unconscious patients, because in such cases it is quickly swallowed reflexly; hence also it is commonly given to those who are unconscious from apoplexy. It must never be administered to children, to pregnant women, to feeble subjects, to those with haemorrhoids, nor to those suffering from peritonitis, gastritis, or enteritis.