Medications in Lactation
| Drug | M/PAUC | % maternal dose | Comments | |
| Acid-suppressants: | ||||
| Cimetidine | 1.7-5.8 | 5.4-6.7 | Avoid in favour of safer alternatives with lower potential for side effects. May accumulate in milk due to active transport. | |
| Famotidine | 1.5 | 1.6 | Probably safe. | |
| Ranitidine | 2.8 | 5.0-7.8 | Probably safe when restricted to sporadic doses or a single dose at night-time. May accumulate in milk due to active transport. | |
| Analgesics: Analgesics such as paracetamol, ibuprofen, naproxen and codeine are considered to be ‘safe’, due to low transfer into breast milk and few problems with extensive usage. Transfer of aspirin into breast milk appears to be low but it is best avoided due to the theoretical risk of Reye’s syndrome. Sumatriptan has a short half-life of approximately two hours and infant exposure can be almost completely avoided by expressing and discarding breast milk for approximately eight hours after dosing. Limited data on tramadol suggest low transfer into breast milk although where possible, it would be preferable to use agents which are more established such as codeine and paracetamol. Morphine is usually considered ‘safe’ because of low transfer into milk, and high first-pass metabolism. | ||||
| Aspirin | 0.06 | 3.2 | Avoid due to possible association with Reye’s syndrome. | |
| Codeine | 2.16 | 6.8 | Considered safe. | |
| Ibuprofen | 0 | < 0.6 | Considered safe. Not detected in milk. | |
| Indomethacin | 0.37 | < 1.0 | Considered safe. One case of seizures (causality questionable). | |
| Mefenamic acid | ID | 0.3 | Probably safe. | |
| Methadone | 0.47 | 2.2 | Considered safe in methadone maintenance as 60% of infants born to mothers in maintenance programmes develop symptoms of withdrawal. | |
| Morphine | 2.46 | 0.4 | Considered safe. | |
| Naproxen | ID | 1.1 | Probably safe. | |
| Nefopam | ID | 0.4 | Probably safe. | |
| Piroxicam | ID | 5-10 | Use a NSAID with a shorter half-life where possible. | |
| Paracetamol | 0.8 | 2.9-7.9 | Considered safe. | |
| Sumatriptan | 4.1-5.7 | 0.3-6.7 | Exposure limited by low oral availability in term infants. Expressing for 8 hours post-dose will almost completely avoid exposure. | |
| Antibiotics: Antibiotics such as penicillins, cephalosporins and macrolides are considered to be compatible with breastfeeding although there are theoretical risks of alterations to infant bowel flora and allergic sensitisation. The safety of metronidazole is controversial due to the possibility of high transfer into breast milk. The weight-adjusted infant dose may be as high as 36% of the maternal dose indicating that infant exposure may be higher than the arbitrary cut-off of 10%. Techniques that may be considered for minimising infant exposure include choosing an alternative antibiotic such as amoxycillin/clavulanic acid (if appropriate), alternating breast and bottle feeding, or withholding breastfeeding during the treatment course. If breastfeeding is to be withheld, the mother should be encouraged to continue to express breast milk while on the antibiotic course but to discard the milk. This will help to maintain lactation and enable the mother to resume breastfeeding at the end of the course. The transfer of tetracyclines into breast milk is low but they are usually avoided due to the possible risks of inhibiting bone growth or causing dental staining. Fluoroquinolones should also be avoided in breastfeeding as they have been reported to cause arthropathies in immature animals. Sulphonamides such as sulphamethoxazole are unlikely to be problematical in most situations but are best avoided in infants with hyperbilirubinaemia or glucose-6-phosphate dehydrogenase deficiency. | ||||
| Aminoglycosides | ||||
| Gentamicin | 0.17 | 2.2 | Considered compatible with breastfeeding due to low transfer and low oral availability. | |
| Cephalosporins |  | Considered safe. Low transfer into milk. Third generation cephalosporins have greater potential to alter bowel flora. | ||
| Cefaclor | ID | 0.7 | ||
| Cefalexin | 0.09 | 0.5-1.2 | ||
| Cefotaxime | ID | 0.3 | ||
| Ceftriaxone | 0.04 | 0.7-4.7 | ||
| Fluoroquinolones | ||||
| Ciprofloxacin | 2.17 | 4.8 | Avoid fluoroquinolones due to theoretical risk of arthropathies. | |
| Macrolides | | Considered safe. May alter bowel flora. | ||
| Clarithromycin | 0.25 | 1.8 | ||
| Erythromycin | 0.41 | 2.1 | ||
| Penicillins | | Considered safe. Note: although amoxycillin/clavulanic acid combination is used extensively in lactation, there are no published data on the safety of clavulanic acid. | ||
| Amoxycillin | ID | 0.7 | ||
| Benzylpenicillin | 0.37 | 0.8 | ||
| Phenoxymethyl-penicillin | ID | 0.25 | ||
| Tetracyclines | | Avoid tetracyclines where feasible due to the possible risks of dental staining and adverse effects on bone development. | ||
| Minocycline | ID | 3.6 | ||
| Tetracycline | 0.58 | 4.8 | ||
| Others | ||||
| Aciclovir | ID | 1.1-1.2 | Considered safe. No adverse effects noted in breastfed infants. | |
| Fluconazole | 0.75 | 11 | Potential for accumulation particularly in premature infants. | |
| Metronidazole | 0.9-1.1 | 0.1-36.0 | Controversial as exposure may be high. With high doses consider expressing and discarding milk. | |
| Nitrofurantoin | ID | 0.6-6.0 | Avoid in G6PD-deficient infants (due to the risk of haemolysis). | |
| Sulphamethoxazole & Trimethoprim (i.e. co-trimoxazole) | 0.1 1.26 | 2-2.5 3.8-5.5 | Avoid suphaemethoxazole in infants with hyperbilirubinaemia and G6PD deficiency. | |
| Anticoagulants Heparins (unfractionated and low molecular weight) are considered ‘safe’ since these agents have a large molecular weight and do not cross into breast milk to a significant extent. They are also poorly absorbed. Warfarin is also considered to be compatible with breastfeeding as transfer is low, and adverse effects and changes in prothrombin time have not been detected in breastfed infants. However, it would be prudent to monitor the infant’s prothrombin time during treatment. | ||||
| Warfarin | 0 | < 4.4 | Probably safe. No changes in prothrombin times detected in breastfeeding infants. Monitor prothrombin time. | |
| Anticonvulsants: Carbamazepine, phenytoin and sodium valproate are generally considered to be compatible with breastfeeding although the infant should be observed for evidence of central nervous system depression. Available data on the safety of lamotrigine in breastfeeding suggest that transfer into breast milk may be considerable and therapeutic concentrations have been detected in breastfed infants. There are insufficient published data to comment on the safety of gabapentin in breastfeeding. | ||||
| Carbamazepine | 0.36-0.39 | 2.8-7.3 | Considered safe. Monitor for sedation, poor suckling. | |
| Lamotrigine | ID | 10-22 | Concentrations in breastfed infants have been consistent with those expected to produce clinical effect. Best to avoid. | |
| Phenobarbitone | ID | 23-156 | Avoid due to high infant exposure. | |
| Pheyntoin | 0.13-0.18 | 3.0-7.2 | Considered safe. Observe for sedation, poor suckling. One report of methaemoglobinaemia, poor suckling and sedation. | |
| Sodium valproate | 0.05 | 1.8 | Considered safe at low doses. High doses may increase the risk of hepatitis. | |
| Vigabatrin | ID | <1% | Avoid until further data are available. | |
| Antidepressants: | ||||
| Tricyclics: | | Probably safe. Negligible or no concentrations detected in breastfed infants. | ||
| Amitriptyline | 0.83 | 0.6-0.9 | ||
| Desipramine | ID | 0.5-1.0 | ||
| Dothiepin | 0.8-1.6 | 0.2-1.5 | ||
| Doxepin | ID | 0.01 | ||
| Imipramine | ID | 0.13 | ||
| Nortriptyline | ID | 0.53 | ||
| SSRIs | ||||
| Selective serotonin reuptake inhibitors (SSRIs) transfer into breast milk to varying extents. Paroxetine is reported to have the lowest transfer into breast milk (weight-adjusted infant dose 1-3%). Fluoxetine transfers to a greater extent (weight-adjusted infant dose ≤ 14%) and its active metabolite, norfluoxetine, has a long half-life of one to two weeks and may accumulate in a breastfed infant. Data on citalopram (weight-adjusted infant dose approximately 5%) suggest that the relative infant dose of citalopram is intermediate between paroxetine and fluoxetine. Based on these data, paroxetine is the preferred SSRI in breastfeeding women. | ||||
| Others | ||||
| Moclobemide | 0.72 | 1.6 | Probably safe. | |
| Antiemetics: | ||||
| Domperidone | ID | 0.05 | Probably safe. May increase milk secretion. | |
| Metoclopramide | ID | 4.7-11.3 | Low dose or sporadic use probably safe. May increase milk secretion. | |
| Antihistamines: | ||||
| Loratadine | 1.2 | 0.7 | Probably safe. No adverse effects reported in infants. | |
| Triprolidine | 0.53 | 0.9 | Considered safe. | |
| Antipsychotics: | | Probably safe. May increase milk secretion. Monitor infant for sedation, irritability etc. | ||
| Chlorpromazine | ID | 0.2 | ||
| Flupenthixol | ID | 0.5-0.8 | ||
| Haloperidol | ID | 0.15-2.0 | ||
| Cardiovascular: | ||||
| Amiodarone | ID | 37 | Avoid in breastfeeding. | |
| Atenolol | 2.3-4.5 | 5.7-19.2 | Avoid in favour of antihypertensives with lower infant exposure. | |
| Captopril | 0.03 | 0.014 | Considered safe. | |
| Digoxin | 0.6-0.9 | 2.3-5.6 | Considered safe. | |
| Diltiazem | 0.98 | 0.9 | Unlikely to be problematical in breastfeeding. | |
| Enalapril | 0.02 | < 0.1 | Considered safe. | |
| Metoprolol | 2.8-3.6 | 1.7-3.3 | Probably safe. | |
| Nadolol | 4.6 | 5.1 | Consider choosing a beta-blocker with a lower infant dose, if feasible. | |
| Propranolol | 0.32-0.76 | 0.2-0.9 | Probably safe. | |
| Quinapril | 0.12 | 1.6 | Considered safe. | |
| Verapamil | 0.6 | 0.14-0.84 | Considered safe. | |
| Sedatives/hypnotics: | ||||
| Clonazepam | ID | 1.5-3.0 | Short-term use of low doses is probably safe. | |
| Diazepam | 0.16 | 2.0-2.3 | Reasonable to breastfeed after a low single dose but potential for accumulation with prolonged use. Sedation has been reported in breastfed infants. | |
| Lorazepam | ID | 2.2 | Short-term use of low doses is probably safe. | |
| Midazolam | 0.16 | 0.7 | Short-term use of low doses is probably safe. | |
| Nitrazepam | ID | ID | Short-term use of low doses is probably safe. Potential for accumulation with prolonged administration. | |
| Zopiclone | 0.5 | 4.1 | Short-term use of low doses is probably safe. | |
| Social Drugs: Infant exposure following maternal ethanol ingestion may be as high as 20% and has been associated with impaired psychomotor development. Alcohol consumption should be minimised during lactation (e.g. by withholding breastfeeding for about two hours after ingestion of a standard alcoholic drink). ———- Caffeine exposure may be as high as 34% of the weight-adjusted maternal dose and side effects such as restlessness and irritability have been reported in infants exposed via breast milk. ———- Nicotine has been detected in the plasma of breastfed infants, and smoking is best avoided by breastfeeding mothers. The use of nicotine replacement therapy (e.g. transdermal delivery systems) in breastfeeding mothers should be considered in terms of risks and benefits. However, as a general rule, the short-term use of nicotine replacement therapy is far preferable than continued smoking. | ||||
| Cannabis (THC) | ID | ID | Avoid as long-term effects are unknown. | |
| Caffeine | 0.5-0.8 | 0.6-21.0 | Low intake probably safe. Restlessness and irritability documented. Prolonged half-life (80-100 hours) in neonates. | |
| Ethanol | 0.9 | 3-4 | Occasional low usage probably safe. Chronic intake may be associated with impairment of psychomotor development. Consider withholding breastfeeding for 1-2 hours per standard drink. | |
| Nicotine | 2.92 | ID | Cigarette smoking should be avoided due to health hazards associated with smoking. Use of nicotine patches may be considered compatible with breastfeeding and is favoured over smoking. | |
| Miscellaneous: | ||||
| Ethinyloestradiol | ID | 0.3 | May suppress lactation. | |
| Levonorgestrel | ID | 1.1 | Considered safe. | |
| Medroxyprogesterone | ID-0.72 | 3.4-5.0 | Considered safe. | |
| Norethisterone | ID-0.26 | 0.02-1.9 | Considered safe. | |
| Prednisone | ID | 0.26 | Short courses of low doses (≤ 20mg daily) are probably safe. Note: there are insufficient data on other systemic corticosteroids (e.g. betamethasone, dexamethasone). | |
| Pseudoephedrine | 2.5 | 4.0 | Low doses or sporadic use probably safe. | |
| Sulphasalazine | ID | 1.2-7.0 | Avoid in infants with hyperbilirubinaemia or G6PD deficiency. | |