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.
If given in the prodromal stage of an attack of migraine, the bromides often succeed in preventing its development, and especially when the head-pain and the nerve-disturbance precede, or are more prominent than the nausea or gastric disorder (Yandell, Latham). Five grains every hour or half-hour may be given, but if an attack has already set in, a full dose of 20 to 30 gr. is better, and if this produces sleep, the patient usually wakes free from headache. After the paroxysm has fully set in, the remedy does not seem to control it (Medical Times, i., 1875, p. 338).
In ordinary congestive headache, with flushed face, and intolerance of light and noise, and in congestive neuralgia generally, the bromides are serviceable; also in the headache occurring in delicate children from even moderate application to study. Dr. Day recommends their use with iodides for children who suffer from constant headache and debility (Lancet, i., 1875, p. 854); but I have been disappointed with this combination under such circumstances.