Most drugs that are present in a mother's plasma appear to some extent in her milk though the amounts are so small that loss of drug in milk is of no significance as a mechanism of elimination.22 Even small amounts, however, may sometimes be of significance for the suckling child whose drug metabolic and eliminating mechanisms are immature.
Whilst most drugs taken by the mother pose no hazard to the child, there are exceptions, as follows:
DRUGS AND BREAST FEEDING23
Alimentary tract. Sulphasalazine may cause adverse effects and mesalazine appears preferable.
Anticancer. Regard as unsafe because of inherent toxicity.
Antidepressants. Avoid doxepin, a metabolite of which may cause respiratory depression.
Antiarrhythmics (cardiac). Amiodarone is present in high and disopyramide in moderate amounts but effects in the infant have not been reported.
Antiepilepsy. General note of caution: observe the infant for sedation and poor suckling. Primidone, ethosuximide and phénobarbital are present in milk in high amounts; phenytoin and sodium valproate less so.
Anti-inflammatory. Regard aspirin (salicylates) as unsafe (possible association with Reye's syndrome).
Antimicrobials. Metronidazole is present in milk in moderate amounts; avoid prolonged exposure. Nalidixic acid and nitrofurantoin should be avoided where glucose-6-phosphate dehydrogenase deficiency is prevalent. Avoid clindamycin, dapsone, lincomycin, sulphonamides. Regard chloramphenicol as unsafe.
Antipsychotics. Phenothiazines, butyrophenones and thioxanthenes are best avoided unless the indications are compelling: amounts in milk are small but animal studies suggest adverse effects on the developing nervous system. In particular,
22 But after mercury poisoning breast milk is a major route of elimination.
23 Bennett P N (ed) 1996 Drugs and human lactation. Elsevier, Amsterdam.
moderate amounts of sulpiride enter milk. Lithium is probably best avoided.
Beta-adrenoceptor blockers. Neonatal hypoglycaemia may occur. Satalol and atenolol are present in the highest amounts.
Hormones. Oestrogens, progestogens and androgens suppress lactation in high dose. Oestrogen/ progestogen oral contraceptives are present in amounts too small to be harmful but may suppress lactation if it is not well established.
Miscellaneous. Bromocriptine suppresses lactation. Caffeine may cause infant irritability in high doses.
Was this article helpful?