This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
2. Local or External Use. Under this head, it is intended to embrace all those modes of using the remedy, in which it is brought into direct contact with the seat of its intended operation through extraneous agency, including injection into the various passages opening externally, as well as application to the surface of the body. In these it acts upon the same principles as when used internally. But it is more especially for its antiphlogistic effects that it is employed. As a mere styptic, either for arresting hemorrhage, or controlling increased secretion unconnected with inflammation, as excessive sweating for example, it is less efficient than alum, or probably the vegetable astringents. In reference to the mucous surfaces, it is, as a general rule, better adapted to the earliest stage of inflammation, or the very advanced stage when suppuration has taken place, or to the chronic forms of the affection, than to the condition of acute inflammation in full vigour. But this remark does not apply to affections of the skin, protected by the cuticle.
In chronic inflammation of the nasal passages, with purulent discharge, a solution containing from ten to twenty grains to the fluid-ounce of water, may be injected or otherwise introduced into the nostrils, once or twice daily, with hope of benefit. Care, however, should be taken, in such cases, that none of the solution is swallowed.
Chronic suppuration of the auditory meatus may be treated in a similar manner; though it would be prudent to commence with a weaker solution, say from two to five grains to the fluidounce, and to increase if found necessary.
As a mouth wash or gargle, acetate of lead is chiefly employed in cases of mercurial salivation, in which it is one of the best applications. For this purpose, the solution may have the strength of two or three grains to the fluidounce to begin with. It often blackens the teeth and tongue, in consequence of the formation of sulphuret of lead, through reaction with the sulphur contained in the salivary liquids. But this discoloration is of no serious importance, and gradually disappears. In ordinary ulceration, or pseudomembranous affections of the mouth and fauces, sulphate of zinc, or nitrate of silver, in solution, is more effectual than the salts of lead.
In certain cases of dysentery affecting the rectum especially, and attended with little general disturbance of the system, a solution of acetate of lead, injected into the rectum, often serves au excellent purpose. It will sometimes put an almost immediate end to cases, which have proved tedious under other treatment. From four to six fluidounces of a solution, containing two or three grains of the acetate in each,fluidounce, with thirty or forty drops of laudanum in the whole quantity, should be injected three times a day. The laudanum is useful by facilitating the retention of the liquid, as well as by directly calming irritation. It is true that the meconate of morphia is converted into the acetate, while a little insoluble meconate of lead is formed; but this result is of no practical importance. It may be obviated, however, by substituting for the laudanum one-quarter or one-third of a grain of acetate of morphia.
Enemata composed of ten grains of acetate of lead, dissolved in six fluidounces of warm water, and administered every two hours, are said to have been used, with remarkable success, in strangulated hernia.
In gonorrhoea and leucorrhoea, injections of the salt are often very useful. For the effectual treatment, however, of these affections, the solution should be very frequently repeated, so that the impression may be steadily maintained. In gonorrhoea, the injection should be administered not less than six times a day, at equal intervals. It should be at first of the strength of two or three grains to the fluidounce, which may be increased if necessary.
Perhaps for no purpose is this salt more employed than for the relief of inflammatory affections of the skin and the subcutaneous tissue. In erysipelas, when the inflammation is very high; in the more inflammatory forms of erythema, as E. nodosum; in certain cases of herpes, eczema, and other cutaneous eruptions attended with much heat, pain, and redness; in inflammation of the subcutaneous areolar tissue, either arising spontaneously, as in phlegmon, or resulting from sprains, bruises, etc., and in acute swelling of the external lymphatic glands, a solution of acetate of lead is often highly useful in the alleviation or cure of the inflammation. For these purposes, two drachms of the acetate may be dissolved in a pint of soft water; the turbidness being corrected by a fluidrachm of vinegar or diluted acetic acid. In some cases, laudanum or acetate of morphia may be usefully added. The solution may be applied by means of folded linen wet with it, or in the form of the cold poultice, made by mixing the solution with crumb of bread, and enclosing the soft mass in linen or gauze.
It is customary, in cases of superficial inflammation, particularly the erysipelatous, to apply mucilaginous solutions with a view to their antiphlogistic effect. This may be increased by the addition of acetate of lead to the solution; but it should be remembered that this salt is incompatible with certain mucilages, particularly with those of slippery elm and quince-seeds, with which it forms precipitates, and thus deprives the liquid of its mucilaginous property. But with the mucilages of flaxseed and the pith of sassafras it reacts but slightly, not sufficiently to impair materially their demulcent properties, or to interfere with its own efficiency. These latter mucilages, therefore, should always be selected, preferably to those first mentioned, for external use in connection with acetate of lead. Thus, we may add this salt with propriety to an eyewash of mucilage of sassafras pith, often used in ophthalmia, while it would be incompatible with mucilage of quince-seeds, also used for the same purpose.
In irritable or inflamed ulcers, and those attended with very profuse discharges, and in inflamed blistered surfaces, a solution of acetate of lead may also be used, but of not more than half the strength of that employed where the cuticle is entire. In these cases, the acetate often reacts with the albumen and salts of the secreted liquid, producing a white insoluble compound. This is ordinarily of no inconvenience; but, in ulcers of the cornea, there is danger that this compound may become permanently incorporated with (he tissue, forming an opaque spot, which cannot be removed. In this affection, therefore, the salt should not be used.
Acetate of lead may be given in pill or solution. The pill is best made with mucilage of gum arabic and syrup, as these are not incompatible with the salt. It should be prepared as wanted for use. Opium is often combined with the salt; and, though mutual decomposition may take place between the meconate of morphia and acetate of lead, no practical disadvantage results. Nor is the addition of the vegetable astringents improper, as the resulting tannate of lead is efficient. When the salt is given in solution, the preparation is rendered more elegant by the addition of a few drops of acetic acid, or a little distilled vinegar; but Dr. Thomson was mistaken in thinking that the poisonous effects of the lead could in this way be prevented. Colica pictonum has followed the use of the acetate thus protected. Indeed, it may be considered nearly certain that the salt is always decomposed in the stomach, whether given with or without a little acetic acid. Laudanum renders the solution turbid by the formation of meconate of lead; but its efficiency is not impaired. The other incompatibles before referred to (see page 156) should be avoided in connection with the salt in solution, though many of them may be given with it in the pilular form.
The dose of acetate of lead is from one to three grains, which, in acute cases, may be repeated every hour, two, or three hours, and in chronic cases, three or four times daily.
In the form of ointment or cerate, the acetate of lead may be employed as a dressing for irritable or inflamed ulcers, excoriated surfaces, and blisters, and may be prepared by thoroughly rubbing together half a drachm of the salt very finely powdered, and an ounce of simple ointment; but the cerate of the subacetate is preferable, for the purposes mentioned.