Simple Reference Guide
The following information is provided as a simple reference guide to the safety of drugs passing through breastmilk. It does not take into consideration special situations like prematurity, difficulties with the infant's hepatic or renal systems, or polypharmacy. However, it is intended to provide a quick and easy method of accessing data on commonly prescribed drugs. Much of the information is taken from Hale (2010), supported by Briggs (2004), Lee (2000) and searches of the Midwifery information and resource service (MIDIRS) together with recommendations by the WHO on maternal medication (2002).
Anaesthetics – local
Anaesthetics – general
Analgesics
Anthelmintics
Antibiotics
Antidepressants
Oral contraceptives
Dental fillings
Loperamide
Drugs of misuse
Alternative and complementary remedies
Thyroid medication
Drugs which inhibit lactation
Drugs which stimulate lactation
Local anaesthetics
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingLidocaine / 0.4 / 1.8 hours / 70% / no evidence of sufficient levels reaching breastmilk / compatible with breastfeeding
General anaesthetics
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingPropofol / unknown (transfer likely to be very low) / anaesthesia time is very short (3-10 minutes) / 99% / See comments / generally considered compatible with breastfeeding
Alcohol / 1 / 0.24 hours / 0 / Occasional, social drinking is unlikely to cause any harm avoid co-sleeping if either the mother or father have drunk alcohol. Chronic, excessive consumption is dangerous to the baby / generally considered compatible with breastfeeding on occasional, low level
Analgesics
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingParacetamol / 0.91-1.42 / 2 hours / 25% / compatible with breastfeeding
Ibuprofen / not defined as transfer so low / 1.8-2.5 hours / > 99% / compatible with breastfeeding
Codeine / 1.3-2.5 / 2.9 hours / 7%; / colic and constipation in the baby reported
4 case reports of neonatal apnoea with 60mg codeine / generally considered compatible with breastfeeding
Morphine / 1.1-3.6 / 1.5 – 2 hours / 35% / poor oral bioavailability so levels reaching the infant through breastmilk are unlikely to lead to clinically significant levels / generally considered compatible with breastfeeding in therapeutic use
Pethidine / 0.84-1.59 / 3.2 hours / 65-80% / The half life is extended only to neonates / generally considered compatible with breastfeeding
Aspirin / 0.03-0.08 / 2.5-7 hours / 88-93% / remote risk of association with Reye’s syndrome
safe as antiplatelet / Not generally considered compatible with breastfeeding
Anthelmintics
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingMebendazole / ratio unknown / 2.8-9 hours / high / poorly absorbed orally / generally considered compatible with breastfeeding
Piperazine / no data / no data / no data / poorly absorbed orally / generally considered compatible with breastfeeding
Antibiotics
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingAmoxycillin / 0.014-0.043 / 1.7 hours / 18% / Penicillins are all safe to take during breastfeeding / generally considered compatible with breastfeeding
Cefaclor / unknown / 0.5-1 hour / 25% / Cephalosporins are all safe to take during breastfeeding / generally considered compatible with breastfeeding
Tetracycline / 0.58-1.28 / 6-12 hours / 25% / drug forms a chaelate with the calcium in the milk and is not absorbed by the baby / Long courses e.g. for acne should be avoided. Short courses generally safe
Gentamicin / 0.11-0.44 / 2-3 hours / <10-30% / Aminoglycocides are not absorbed from the gut so any passing through breastmilk will not be absorbed by the baby / generally considered compatible with breastfeeding
Erythromycin / 0.92 / 1.5-2 hours / 84% / Macrolides are safe to be taken during breastfeeding / generally considered compatible with breastfeeding
Metronidazole / 1.15 / 8.5 hours / 10% / Said to cause milk to taste unpleasant / generally considered compatible with breastfeeding
Ofloxacin / 0.98-1.66 / 5-7 hours / 32% / Quinolones can cause problems in the joints of juvenile animals exposed to them directly. The relevance to breastfeeding is unknown. Short maternal courses are unlikely to pose problems, other antibiotics are preferable / Avoid if possible but consider benefit:risk
Ciprofloxacin / >1 / 4.1 hours / 40% / As above / Avoid if possible but consider benefit:risk
Trimethoprim / 1.25 / life 8-10 hours(neonate up to 40 hours) / 44% / compatible with breastfeeding
Vancomycin / not determined / 5.6 hours / 10-30% / oral bioavailability is poor so absorption is likely to be minimal / Probably safe but no studies
Antidepressants
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingImipramine / 0.5-1.5 / 8-16 hours / 90% / No adverse effects have been noted in case reports. / generally considered compatible with breastfeeding
Fluoxetine / 0.286-0.67 / 2-3 days / 94.5% / Some evidence of excessive somnolence in newborn if exposed in utero / generally considered compatible with breastfeeding
Citalopram / 1.16-3 / 36 hours / 80%. / No information on escitalopram / generally considered compatible with breastfeeding
Paroxetine / 0.056-1.3 / 21 hours / 95% / Some evidence of neonatal withdrawal syndrome if exposed in utero. / generally considered compatible with breastfeeding
Sertraline / 0.89 / 26-65 hours / 98% / This may be the SSRI of choice for most breastfeeding mothers.
Venlafaxine / not confirmed (2.5 in study of 3 mothers) / 5 hours / 27% / The dose transferred to the infant is relatively high and although no adverse reports have been reported it may be wise to use this drug with caution / Use with caution
Contraceptives
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingProgesterone only contaceptives / Transfer into milk is low / compatible with breastfeeding
Progesterone only depot injections and implants / reports that very early progesterone diminishes breastmilk production / compatible with breastfeeding
Combined oral contraceptive pills / oestrogen has an inhibitory effect on prolactin and can dramatically reduce milk production / Should be avoided in breastfeeding
Emergency Hormonal Contraception / compatible with breastfeeding
Dental Fillings
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingamounts of mercury absorbed are minute and passage into breastmilk has not been shown to have any health consequences / compatible with breastfeeding
Loperamide
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeeding0.5 / 10.8 hours / Not reported / 4mg dose reported to produce a milk level of 0.27 microgrammes per litre, / compatible with breastfeeding
Drugs of Misuse
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingHeroin / 2.45 / 1.5-2 hours / 35% / Sufficient quantities of heroin excreted into breastmilk to cause addiction in the baby. If feeds are delayed or the infant suffers withdrawal. / To be discouraged in breastfeeding mothers.
Methadone / 0.68 / 13-55 hours / 89% / Daily doses of methadone of up to 80mg appear to be relatively safe.
Neonatal abstinence syndrome due to exposure in utero / generally considered compatible with breastfeeding <80mg/day
Cannabis / 8 / 25-57 hours / 99.9% / In animals shown to inhibit prolactin and decrease milk production but not been reported in humans / Occasional recreation use would not appear to produce a significant risk to infants but few long term studies
Cocaine / not determined / 0.8 hours / 91%. / Milk may be positive for 36 hours, very toxic to infants / This drug is not safe to be taken by a breastfeeding mother.
Ecstasy. / No studies / derivation from amphetamines suggests that it has the potential to pass into breastmilk in large amounts / To be discouraged in breastfeeding mothers. Discard milk for at least 24 hours after consumption
Alternative and complementary remedies
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingHomeopathic / very little data on transfer / Seek advice from qualified practitioners / Homeopathic remedies unlikely to be harmful
Herbal remedies / very little data on transfer / Seek advice from qualified practitioners / Safety varies – no evidence of harm from echinacea or St John’s Wort,
Smoking / Babies whose mothers smoke are more likely to suffer from colic and breastmilk production is lower in mothers who smoke
Passive smoking is associated with early onset wheeze.
Risk of cot death increased / Common exposure but best avoided
Nicotine replacement therapy / Not licensed to be used by breastfeeding mothers but nicotine exposure is much lower than with smoking. / Safer than exposure to nicotine from smoking
Thyroid medication
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingLevothyroxine / not determined / 6-7 days / 99% / Replaces physiological insufficiency.
Too low a level inhibits prolactin and produces poor milk supply / compatible with breastfeeding
Carbimazole / 0.3-0.7 / 6-13 hours / 0% / sub clinical levels of the active metabolite methimazole enter milk following doses of 30mg per day carbimazole / generally considered compatible with breastfeeding <30mg/day
Propylthiouracil / 0.1 / 1-2 hours / 90% / secreted into breastmilk in amounts too low to produce side effects / compatible with breastfeeding
Vaccinations / Poor oral bioavailability produces low absorption. / compatible with breastfeeding
Oral Polio vaccine / may reduce the production of antibodies by the infant in response to its own dose if given before 6 weeks / compatible with breastfeeding
after infant > 6 weeks old
Drugs which inhibit lactation
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingBromocriptine / not determined / 50 hours / 90-96% / Not recommended for routine suppression of lactation. Some fatalities recorded in mothers taking it / Not advised
Cabergoline / no data on transfer into breastmilk reported / The dose to irreversibly inhibit lactation is 1mg as a single dose on the first day post partum, or 250 microgrammes (half a tablet) every 12 hours for 2 days / Breastfeeding after use unlikely to be possible
Drugs which stimulate lactation
Drug /Milk Plasma Ratio
/ Half life / Plasma protein binding / Comments / Safety in breastfeedingMetoclopramide / 0.5-4.06 / 5-6 hours / 30% / extra-pyramidal symptoms and severe depression reported / Generally compatible but not first choice to stimulate prolactin
Domperidone / 0.25 / 7-14 hours / 93%. / Useful to stimulate breastmilk production if mother has been expressing long term. Refer to specialist breastfeeding expert for support / compatible with breastfeeding