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.
Speaking generally, we may say that bromides act as sedatives upon the genital system, and diminish the sexual feelings and the power of erection, though the secretion of the testicles is not lessened (Rabuteau). But we must recognize that genital excitement may arise either from eccentric cause (as urethral irritation, rectal or ovarian congestion, etc.), or from a centric cause in the mind, cord, or brain itself. It is the former that is controlled by bromide, and there is some reason to think with Dr. Bill that its effect is mainly local, and exerted through the mucous membrane of the urethra, although, no doubt, some effect may be attributed to a lessening of congestion in the spinal cord (v. p. 113). The degree of sedation induced by bromides varies in different men and in male animals, and is shown only under the influence of large doses. It is said not to be exerted in the female sex, though there is clinical evidence of these medicines lessening uterine and ovarian congestion and irritation.
The primary effect of moderate doses of bromide is to lessen most of the secretions (Bowditch and others), although, as a secondary effect, or after very large doses, they may be increased. There is no lachrymation, salivation, or catarrh from a pure salt, as there is from the iodides, for bromides are more stable, and, although also eliminated by mucous membranes, do not part with free bromine on their surface. The mouth is rendered rather drier than usual, especially by the sodium salt. The amount of mucus in the intestinal canal is also lessened, so that constipation is not infrequent at first. The secretion of milk is lessened by the internal and local use of bromide of potassium (Tyler Smith: Medical Times, i., 1861). With regard to the amount of urine excreted, the usual result is that with small or moderate doses no increase can be made out, while with large or long-continued ones, diuresis occurs. Dr. Bowditch suggests that a secondary hyperaemia is determined more readily in the kidneys than in other parts, and Pletzer has reported albuminuria in some instances.
Bromides tend to lessen vesical irritability, and so to render micturition less frequent, though the amount passed may be really larger than usual. On the other hand, very large doses may so far paralyze the sphincter as to occasion incontinence.