Additional information relating to breastfeeding

To be used in conjunction with individual drug entries for specific information and guidance.

Many of the drugs covered by this broad section are used for a variety of indications other than hypertension. Drugs from different pharmacological sections may be used in combination with, or as a replacement for, each other for both hypertension and other cardiovascular indications. Choice of drug in a breastfeeding mother may, therefore, be dependant on a number of issues, including patient-specific clinical conditions and local/national guidelines, which will impact on the choice of drug for a breastfeeding mother and the alternatives that may be considered or are appropriate.

Angiotensin-converting enzyme inhibitors

The evidence for the safe use of ACE inhibitors in breastfeeding is very limited. Small amounts of ACE inhibitors can cause hypotension in premature infants and neonates when used therapeutically. It is, therefore, advised to monitor infants, especially premature and newborn, for hypotension if exposed to an ACE inhibitor while breastfeeding.

Captopril and enalapril are considered to be compatible with breastfeeding, although monitoring advice still applies.

Angiotensin-II receptor antagonists

There is no published evidence of the safe use of any drug in this group during breastfeeding. ACE inhibitors, captopril and enalapril, are considered to be possible alternatives. Premature and newborn infants are theoretically at risk from hypotension when exposed to angiotensin-II antagonists in breast milk. Therefore, it is advised to monitor breastfed infants for hypotension.

Centrally acting antihypertensives
(includes clonidine, methyldopa, moxonidine)

Methyldopa is considered compatible with breastfeeding. Other drugs in this class should be used with caution, especially in premature and newborn infants, with infant monitoring for hypotension. Consider using an alternative antihypertensive (e.g. methyldopa, propranolol, labetalol, hydralazine) – choice will depend on clinical situation.

Beta-adrenoceptor blockers

Clinical properties of beta blockers vary widely with indications varying between hypertension, angina, myocardial infarction, heart failure, arrhythmias, thyrotoxicosis and anxiety. Therefore, propranolol may not always be a suitable clinical alternative. Sotalol is not included in this section as it is used solely for paroxysmal supraventricular arrhythmias.

In general, beta blockers that are considered to pose less risk to a breastfeeding infant have, or are predicted to have, lower levels in breast milk (due to a high degree plasma protein binding, low lipid solubility and a short half-life) and relatively low renal excretion. The risks of currently available beta blockers vary widely due to these features.

Propranolol is considered to be the beta blocker of choice in breastfeeding. Metoprolol is also considered to pose a low risk. Acebutolol, atenolol and nadolol are favoured least because of relatively high milk levels and possible side effects in breastfed infants.

Monitor breastfed infants for signs of beta blockade, especially bradycardia.

Calcium-channel blockers

Clinical actions of calcium channel blockers vary widely which give a variety of indications which include hypertension, angina, arrhythmias, Raynaud’s phenomenon and cluster headache. Therefore, nifedipine or verapamil may not always be a suitable clinical alternative.

Nifedipine and verapamil are considered compatible with breastfeeding, including modified-release formulations, which is supported by limited published evidence and clinical experience. Nicardipine is also considered compatible, but with less clinical experience. Nimodipine is used for cerebrovascular conditions and is also considered to be compatible with breastfeeding. Nifedipine is also used for painful nipple spasm in breastfeeding mothers (off-label).

If non-preferred agents are used, monitor the infant for adverse effects.

Vasodilator and other antihypertensives
(includes diazoxide, hydralazine, minoxidil, sodium nitroprusside)

Vasodilator antihypertensives have two main indications: pulmonary arterial hypertension (see separate section) and hypertensive emergencies. These drugs may therefore be used in clinical situations in which mothers are too ill to breastfeed, although appropriate precautions will still need to be taken on recommencing breastfeeding.

Hydralazine is considered compatible with breastfeeding for moderate to severe hypertension.

Alpha-adrenoceptor blockers
(includes doxazosin, indoramin, phentolamine, prazosin, terazosin)

Alpha blockers for essential hypertension should be used with caution, especially in premature and newborn infants, with infant monitoring for hypotension. Consider using an alternative antihypertensive (e.g. methyldopa, propranolol, labetalol, hydralazine) – choice will depend on clinical situation.

Phentolamine is only used for hypertensive episodes in phaechromocytoma prior to surgery. Breastfeeding during these periods is unlikely to take place.

Drugs for pulmonary hypertension
(includes ambrisentan, bosentan, epoporostenol, iloprost, macitentan, sildenafil, tadalfil)

These drugs may be used in clinical situations in which mothers are too ill to breastfeed, although appropriate precautions will still need to be taken on recommencing breastfeeding.