This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In this serious disease antimony often proves useful, especially in the early stages. It first obtained its reputation at a time when spasmodic and catarrhal croup were not well distinguished from the more serious malady, and when recovery from those varieties was reckoned as recovery from true croup; but at present, on account of its depressing effects, most physicians limit its use to a few emetic doses in cases with very severe spasm, and evident obstruction from false membrane (Klemm: Schmidt's Jahrb., Bd. clx., s. 45).
Dr. Elliotson, however, records cases occurring in infants, and treated successfully with 1/4 and even 1/2-gr. doses every four hours - in one case 27 gr., and in another 33 gr. being taken: vomiting occurred, and some tetanic spasm, but good recovery was made from critical conditions. Mr. Meek and others report in the same journal cases where 1/2-gr. and even 1 gr. doses were given with favorable results to children of four and seven years; but, on the other hand, Mr. Kesteven and others record injurious effects (Medical Times, ii., 1856). Professor Bouchut advocates giving 1/6 to 1/3 gr. frequently, until emesis and diarrhoea are produced, and he records several cases of recovery in the second and third stages (Journal fur Kinderkn., May and June, 1861, Lancet, ii., 1872).
I cannot adopt the above doses as quite safe, and think that great caution should be exercised as to their use. I recommend rather a solution to be made with 1 gr. in 4 oz. of water, and of this one teaspoonful (1/32 gr.) may be given every half-hour for four or five doses; it will often suffice to excite vomiting, which, however, is not desirable unless there be evident obstruction in the trachea; so soon as this obstruction is lessened, the remedy should only be given at intervals of two to three hours; the dyspnoea is commonly removed for a time after vomiting, but if it recur, the same effect should be induced again: of course, the patient's strength is to be supported by suitable nourishment, and fomentations, sprays, or other adjuvants may be used. With this plan of treatment I have many times noticed an early abatement of the cough, dyspnoea, and hoarseness, lowering of the pulse-rate, return of natural warmth and color, and quiet sleep. It is true that the sulphate of copper is often preferred as an emetic, but under the sole use of antimony, as described, I have seen very severe and advanced cases relieved, and if the dose mentioned be found really too small in a given instance, it may be cautiously increased.