Appendix 7b: Lactation

HAdministration of some drugs (e.g., ergotamine) to nursing mothers may harm the infant, whereas administration of others (e.g., digoxin) has little effect. Some drugs inhibit lactation (e.g., estrogens).
Toxicity to the infant can occur if the drug enters the milk in pharmacologically significant quantities. The concentration in milk of some drugs (e.g., iodides) may exceed that in the maternal plasma so that therapeutic doses in the mother may cause toxicity to the infant. Some drugs inhibit the infant’s sucking reflex (e.g., phenobarbital). Drugs in breast milk may, at least theoretically, cause hypersensitivity in the infant even when the concentration is too low for a pharmacological effect.
The following table lists drugs:
• which should be used with caution or which are contraindicated in lactation for the reasons given above;
• which are not known to be harmful to the infant although they are present in milk in significant amounts.
For many drugs; insufficient evidence is available to provide guidance and it is advisable to administer only drugs essential to a mother during lactation. Because of the inadequacy of information on drugs in breast milk, the following table should be used only as a guide; absence from the table does not imply safety.

Drug

Comment

Abacavir

Lactation recommended during first 6 months if no safe alternative to breast milk

Acetylsalicylic acid

Short course safe in usual dosage; monitor infant; regular use of high doses could impair platelet function and produce hypoprothrombinaemia in infant if neonatal vitamin K stores low; possible risk of Reye’s syndrome

Acyclovir

Significant amount in milk after systemic administration, but considered safe to use

Alcohol

Large amounts may affect infant and reduce milk consumption

Aminophylline

Present in milk-irritability in infant reported

Amitriptyline

Detectable in breast milk; continue lactation; adverse effects possible; monitor infant for drowsiness

Amoxycillin

Trace amounts in milk; safe in usual dosage; monitor infant

Amoxycillin + Clavulanic acid

Trace amounts in milk

Ampicillin

Trace amounts in milk; safe in usual dosage; monitor infant

Artemether + Lumefantrine

Discontinue lactation during and for 1 week after stopping treatment; present in milk in animal studies

Asparaginase

Lactation contraindicated

Atenolol

Significant amount in milk; safe in usual dosage; monitor infant

Atropine

Small amount present in milk; monitor infant

Azathioprine

Lactation contraindicated

Beclomethasone

Systemic effects in infant unlikely with maternal dose of less than equivalent of prednisolone 40 mg daily; monitor infant’s adrenal function with higher doses

Benzathine benzylpenicillin

Trace amounts in milk; safe in usual dosage; monitor infant

Benzylpenicillin

Trace amounts in milk; safe in usual dosage; monitor infant

Betamethasone

Systemic effects in infant unlikely with maternal dose of less than equivalent of prednisolone 40 mg daily; monitor infant’s adrenal function with higher doses

Bleomycin

Lactation contraindicated

Carbamazepine

Continue lactation; adverse effects possible (severe skin reaction reported in 1 infant); monitor infant for drowsiness;

Ceftazidime

Excreted in low concentrations; safe in usual dosage; monitor infant

Ceftriaxone

Excreted in low concentrations; safe in usual dosage; monitor infant

Chlorambucil

Lactation contraindicated

Chloramphenicol

Continue lactation; use alternative drug if possible; may cause bone-marrow toxicity in infant; concentration in milk usually insufficient to cause ‘grey syndrome’

Chlormethine

Lactation contraindicated

Chloroquine

For malaria prophylaxis, amount probably too small to be harmful; inadequate for reliable protection against malaria, ; avoid lactation when used for rheumatic disease

Chlorpheniramine

Safe in usual dosage; monitor infant for drowsiness

Chlorpromazine

Continue lactation; adverse effects possible; monitor infant for drowsiness

Ciprofloxacin

Continue lactation; use alternative drug if possible; high concentrations in breast milk

Cisplatin

Lactation contraindicated

Clindamycin

Amount probably too small to be harmful but bloody diarrhoea reported in 1 infant

Clomifene

May inhibit lactation

Clomipramine

Small amount present in milk; continue lactation; adverse effects possible; monitor infant for drowsiness

Clonazepam

Continue lactation; adverse effects possible; monitor infant for drowsiness;

Cloxacillin

Trace amounts in milk; safe in usual dosage; monitor infant

Colchicine

Present in milk but no adverse effects reported; caution because of risk of cytotoxicity

Contraceptives, oral

Combined oral contraceptives may inhibit lactation-use alternative method of contraception until weaning or for 6 months after birth; progestogen-only contraceptives do not affect lactation (start 3 weeks after birth or later)

Cyclophosphamide

Lactation contraindicated during and for 36 h after stopping treatment

Cyclosporine

Present in milk-avoid

Cytarabine

Lactation contraindicated

Dacarbazine

Lactation contraindicated

Dactinomycin

Lactation contraindicated

Dapsone

Although significant amount in milk risk to infant very small; continue lactation; monitor infant for jaundice

Daunorubicin

Lactation contraindicated

Dexamethasone

Systemic effects in infant unlikely with maternal dose of less than equivalent of prednisolone 40 mg daily; monitor infant’s adrenal function with higher doses

Diazepam

Continue lactation; adverse effects possible; monitor infant for drowsiness;

Didanosine

Lactation recommended during first 6 months if no safe alternative to breast milk

Diloxanide

Avoid

Doxorubicin

Lactation contraindicated

Doxycycline

Continue lactation; use alternative drug if possible (absorption and therefore discolouration of teeth in infant probably usually prevented by chelation with calcium in milk)

Efavirenz

Lactation recommended during first 6 months if no safe alternative to breast milk

Eflornithine

Avoid

Ephedrine

Irritability and disturbed sleep reported

Ergocalciferol

Caution with high doses; may cause hypercalcaemia in infant

Ergotamine

Use alternative drug; ergotism may occur in infant; repeated doses may inhibit lactation

Erythromycin

Only small amounts in milk; safe in usual dosage; monitor infant

Ethinylestradiol

Use alternative method of contraception; may inhibit lactation; see also Contraceptives, Oral

Etoposide

Lactation contraindicated

Fluconazole

Present in milk; safe in usual dosage; monitor infant

Flucytosine

Avoid

5-Fluorouracil

Discontinue lactation

Fluphenazine

Amount excreted in milk probably too small to be harmful; continue lactation; adverse effects possible; monitor infant for drowsiness

Glibenclamide

Hypoglycaemia in infant

Haloperidol

Amount excreted in milk probably too small to be harmful; continue lactation; adverse effects possible; monitor infant for drowsiness

Halothane

Excreted in milk

Hydralazine

Present in milk but not known to be harmful; monitor infant

Hydrochlorothiazide

Use alternative drug; may inhibit lactation

Hydrocortisone

Systemic effects in infant unlikely with maternal dose of less than equivalent of prednisolone 40 mg daily; monitor infant’s adrenal function with higher doses

Ibuprofen

Amount too small to be harmful; short courses safe in usual doses

Imipenem + Cilastatin

Present in milk-avoid

Indinavir

Lactation recommended during first 6 months if no safe alternative to breast milk

Iodine

Stop lactation; danger of neonatal hypothyroidism or goitre; appears to be concentrated in milk

Isoniazid

Monitor infant for possible toxicity; theoretical risk of convulsions and neuropathy; prophylactic pyridoxine advisable in mother and infant

Ivermectin

Avoid treating mother until infant is 1week old

Lamivudine

Present in milk; lactation recommended during first 6 months if no safe alternative to breast milk

Levamisole

Lactation contraindicated

Levonorgestrel

Combined oral contraceptives may inhibit lactation-use alternative method of contraception until weaning or for 6 months after birth; progestogen-only contraceptives do not affect lactation (preferably start 6 weeks after birth or later)

Lithium

Present in milk and risk of toxicity in infant; continue lactation; monitor infant carefully, particularly if risk of dehydration

Lopinavir + Ritonavir

Lactation recommended during first 6 months if no safe alternative to breast milk

Lumefantrine

See Artemether + Lumefantrine

Medroxyprogesterone

Present in milk-no adverse effects reported (preferably start injectable contraceptive 6 weeks after birth or later)

Mefloquine

Present in milk but risk to infant minimal

6-Mercaptopurine

Lactation contraindicated

Metformin

Present in milk but safe in usual doses; monitor infant

Methotrexate

Lactation contraindicated

Metoclopramide

Present in milk; adverse effects possible; monitor infant for adverse effects

Metronidazole

Significant amount in milk; continue lactation; avoid large doses; use alternative drug if possible

Morphine

Short courses safe in usual doses; monitor infant

Nalidixic acid

Continue lactation; use alternative drug if possible; one case of haemolytic anaemia reported

Nelfinavir

Lactation recommended during first 6 months if no safe alternative to breast milk

Neostigmine

Amount probably too small to be harmful; monitor infant

Nevirapine

Present in milk; lactation recommended during first 6 months if no safe alternative to breast milk

Nifedipine

Small amount in milk; continue lactation; monitor infant

Nitrofurantoin

Only small amounts in milk but could be enough to produce haemolysis in G-6-PD-deficient infants

Norethisterone

Combined oral contraceptives may inhibit lactation-use alternative method of contraception until weaning or for 6 months after birth; progestogen-only contraceptives do not affect lactation (preferably start injectable contraceptive 6 weeks after birth or later)

Ofloxacin

Continue lactation; use alternative drug if possible

Paracetamol

Small amount present in milk: short courses safe in usual dosage; monitor infant

Pentamidine

Avoid unless essential

Pentavalent antimony compounds

Avoid

Phenobarbital

Continue lactation; adverse effects possible; monitor infant for drowsiness;

Phenoxymethylpenicillin

Trace amounts in milk; safe in usual dosage; monitor infant

Phenytoin

Small amount present in milk; continue lactation; adverse effects possible; monitor infant for drowsiness;

Potassium iodide

Stop lactation; danger of neonatal hypothyroidism or goitre; appears to be concentrated in milk

Povidone–iodine

Avoid; iodine absorbed from vaginal preparations is concentrated in milk

Praziquantel

Avoid lactation during and for 72 h after treatment; considered safe to continue lactation in treatment of schistosomiasis

Prednisolone

Systemic effects in infant unlikely with maternal dose of less than prednisolone 40 mg daily; monitor infant’s adrenal function with higher doses

Primaquine

Avoid; risk of haemolysis in G-6-PD-deficient infants

Procainamide

Present in milk; continue lactation; monitor infant

Procarbazine

Lactation contraindicated

Promethazine

Safe in usual dosage; monitor infant for drowsiness

Propranolol

Present in milk; safe in usual dosage; monitor infant

Propylthiouracil

Monitor infant’s thyroid status but amounts in milk probably too small to affect infant; high doses might affect neonatal thyroid function

Pyrimethamine

Significant amount-avoid administration of other folate antagonists to infant

Quinidine

Significant amount but not known to be harmful

Ranitidine

Significant amount present in milk, but not known to be harmful

Ritonavir

See Lopinavir with Ritonavir

Salbutamol

Safe in usual dosage; monitor infant

Saquinavir

Lactation recommended during first 6 months if no safe alternative to breast milk

Senna

Avoid; large doses may cause increased gastric motility and diarrhoea

Silver sulfadiazine

Continue lactation; monitor infant for jaundice-small risk of kernicterus in jaundiced infants particularly with long-acting sulphonamides, and of haemolysis in G-6-PD-deficient infants

Sodium valproate

see Valproic acid

Stavudine

Lactation recommended during first 6 months if no safe alternative to breast milk

Sulfadiazine

Continue lactation; monitor infant for jaundice-small risk of kernicterus in jaundiced infants particularly with long-acting sulphonamides, and of haemolysis in G-6-PD-deficient infants

Sulfadoxine + Pyrimethamine

Continue lactation; monitor infant for jaundice-small risk of kernicterus in jaundiced infants and of haemolysis in G-6-PD-deficient infants (due to sulfadoxine)

Sulfamethoxazole + Trimethoprim

Continue lactation; monitor infant for jaundice-small risk of kernicterus in jaundiced infants and of haemolysis in G-6-PD-deficient infants (due to sulfamethoxazole)

Sulfasalazine

Continue lactation; monitor infant for jaundice-small amounts in milk (1 report of bloody diarrhoea and rashes); theoretical risk of neonatal haemolysis especially in G-6-PD-deficient infants

Tamoxifen

Suppresses lactation; avoid unless potential benefit outweighs risk

Testosterone

Avoid; may cause masculinization in the female infant or precocious development in the male infant; high doses suppress lactation

Tetracycline

Continue lactation; use alternative drug if possible (absorption and therefore discolouration of teeth in infant probably usually prevented by chelation with calcium in milk)

Theophylline

Present in milk-irritability in infant reported; modified-release preparations preferable

Thiamine

Severely thiamine-deficient mothers should avoid lactation as toxic methyl-glyoxal excreted in milk

Trimethoprim

Present in milk; safe in usual dosage; monitor infant

Valproic acid

Small amount present in milk; continue lactation; adverse effects possible; monitor infant for drowsiness; (Sodium valproate)

Vancomycin

Present in milk-significant absorption following oral administration unlikely

Vinblastine

Lactation contraindicated

Vincristine

Lactation contraindicated

Warfarin

Risk of haemorrhage; increased by vitamin-K deficiency; warfarin appears safe

Zidovudine

Lactation recommended during first 6 months if no safe alternative to breast milk