Pregnancy support- Pathology

Lactation - updated: 03 November 2008

Drugs that affect the breast and lactation

Clin Obstet Gynecol. 1975 Jun;18(2):95-111

Dickey RP, Stone SC.

PIP: Drugs that are known to affect breast morphology or breast secretion may be classified into 2 major groups: 1) drugs having a central action on the pituitary or hypothalamus and 2) steroids and several other compounds that act peripherally. Drugs in the 1st group affect lactation through stimulation or suppression of the lactogenic pituitary hormone prolactin. Their action may be directly on the pituitary or indirectly on the hypothalamus where the secretion of hypothalamic prolactin-inhibiting factor is affected. Drugs in the 2nd group act peripherally by exerting their action mainly at the level of breast tubules and acini. The most frequently used are estrogens which stimulate growth of the breast and suppress lactation, and suppress breast cancer in some women. Centrally acting drugs which cause galactorrhea also cause an increase in prolactin secretion, but the presence of estrogen-primed breast tissue is needed. A list of such drugs (including rauwolfia and phenothiazine derivatives, and opiates) is given. The most common mechanism of action by which psychotropic drugs increase prolactin secretion is by interfering with formation or release of dopamine from hypothalamus neurons and its subsequent action via an alpha-adrenergic receptor on hypothalamic cells that secrete prolactin-inhibiting factor. Reserpine and other rauwolfia drugs deplete hypothalamic neurons of catecholamines and prevent their reuptake by nerve endings. Phenothiazines interfere with the action of catecholamines at the alpha-adrenergic receptor sites. Prolonged use of drugs that stimulate pituitary activity may lead to formation of microadenomas of the pituitary. Continuation of galactorrhea for more than 2 weeks after stopping therapy suggest this result. L-dopa suppresses abnormal lactation by reduction in serum prolactin levels. Br-ergocryptine, an ergot derivative, has galactorrhea-blocking and prolactin-suppressing activity but is devoid of alpha-adrenergic activity. Barbiturates and pyridoxine may cause decrease in milk flow of nursing mothers. Peripherally acting drugs consist of estrogen, progesterone, and androgen as well as hypoglycemic-producing agents, thyroid hormone, corticosteroids, and spironolactone. Estrogen is the only steroid effective in suppression of puerperal lactation. There are several steroids effective in causing remission of breast cancer. The presence of an intact pituitary is apparently necessary if estrogens are to be effective in breast cancer. Corticosteroids may be effective in patients insenstive to sex hormones. Cytotoxic agents may be more effective when used in combination with corticosteroids. Galactorrhea occurring in a nulliparous woman taking oral contraceptives is always abnormal and suggests the possibility of a pitutitary tumor. Women with postpill galactorrhea-amenorrhea may also have such tumors. All cases of galactorrhea when sex hormones have been used should be studied for pituitary tumor.

Publication Types:

• Review

Drugs affecting lactation

Semin Perinatol. 1979 Jul;3(3):279-86

Dickey RP.

PIP: The effects of a variety of drugs on lactation are described. Drugs affect lactation either by modifying breast tissue or by influencing prolactin secretion. Androgens and progesterones stimulate the growth of breast tissue, and estrogens, which are frequently used to suppress lactation, stimulate breast duct growth. Many psychotropic drugs increase prolactin levels and cause galactorrhea while other centrally acting drugs inhibit lactation. The names and the mechanism of action of all centrally acting drugs which cause galactorrhea and of all those known to inhibit lactation are provided in tabular form. Suggestions related to the clinical use of the sex steroids and the centrally acting drugs are 1) the use of estrogens to suppress lactation should be limited to the shortest possible time; 2) if galactorrhea occurs in a menopausal patient who is taking oral contraceptives or estrogens, she should be examined for pituitary tumor; 3) if galactorrhea occurs in a patient who is taking a centrally acting drug known to cause galactorrhea, the patient need not be examined for pituitary tumor unless other symptoms are present; 4) the use of centrally acting drugs by women predisposed to breast cancer should be avoided; 5) nursing mothers should avoid taking large doses of barbiturates and pyridoxine as these drugs may reduce lactation; and 6) the use of bromocryptine to suppress postpartum lactation may stimulate early ovulation, and patients should be warned about the need to use contraceptives.

Publication Types:

• Review

Suppression of lactation with high doses of pyridoxine

S Afr Med J. 1975 Dec 6;49(52):2155-6

Marcus RG.

Administration of high doses of vitamins B6, B1 and B12 successfully inhibited lactation without any untoward side-effects or discomfort in 96% of patients who had not yet established lactation, compared with 76,5% of control patients who received placebo.

Publication Types:

• Placebo Controlled

Publication Types:

• Review