Antiallergics, antiasthmatics and antitussives

4.2.1

Antihistamines (H ₁ -blocker)

Antihistamines are used to treat allergic illnesses, as antiemetics ( Chapter 4.3 ) and as sleeping aids.

The newer antihistamines, which have practically no sedative effect, have also proven beneficial during breastfeeding. Following a single dose of 40 mg loratadine (four times the current therapeutic dose) transfer to the infant was calculated at approximately 1% of the effective ingredient (including metabolites) compared to the maternal weight-related dose ( ). Only two infants (3.9%) among 51 exposed to loratadine during breastfeeding showed sedation ( ). There are no data on the passage into mother’s milk of cetirizine , which has a half-life of 9 hours. Previous comprehensive experience, however, does not indicate any noteworthy intolerance while breastfeeding. Terfenadine with an M/P ratio of 0.2 has a half-life of 20 hours. A study of four breastfeeding women indicated less than 0.5% of the weight-related dose for the infant. Only the active metabolites, but not the maternal substance, were detectable in the milk ( ). There is very limited experience with the following non-sedating H ₁ -blockers and no data on their passage into mother’s milk: desloratadine , ebastine , fexofenadine and levocetirizine . There are no observations at all on rupatadine and bilastine .

The older antihistamines with sedating action have become less important and should be reserved during breastfeeding for special conditions. Mild restlessness that does not need treatment and irritability were described in around 10%, and sedation or weak suckling in 1.6% of the children exposed to various antihistamines ( ). None of the manufacturers have data on the relative dose. Twelve hours after the start of maternal treatment with clemastine , a stiff neck, hyper-excitability and sleepiness were observed in a 10-week-old infant; 5–10 μg/L of the drug was detected in the milk. No clemastine was found in the infant’s serum ( ). In addition, the mother had long-term treatment with phenytoin and carbamazepine . Until a few years ago, dimetindene was a common antihistamine. It has a short half-life of 5 to 7 hours, was approved for children from age 1, and is comparatively non-sedating, but it has an atropine-like effect that should not be overlooked. Much less well studied are cyproheptadine , dexchlorpheniramine , hydroxyzine , mizolastine and triprolidine . Azelastine is available for systemic and local use. The latter is considered to be non-problematic but it could alter the milk taste leading to rejection by the infant.

Used exclusively for local therapy are bamipine , chlorphenoxamine and levocabastine as well as the newer substances epinastine and olopatadine . There are no data on passage into the mother’s milk for any of these substances. Their use during breastfeeding is considered unproblematic.

4.2.2

Selective effective β ₂ -sympathomimetics

The inhalable broncholytics fenoterol , salbutamol , albuterol and terbutaline , as well as reproterol , which is only available in a combination preparation, are well-tolerated during breastfeeding.

Only for terbutaline is there data available regarding passage into the mother’s milk – 3.5 μg/L of milk was measured with oral medication of 2.5 or 5 mg, three times a day. The M/P ratio was between 1 and 2. The infant’s intake was a maximum of 0.7μg/kg per day, which was about 0.7% of the maternal dosage per kg bodyweight. No toxic effects were observed ( ). With inhalation use, passage is less than with oral treatment. Excessive overdosing, however, can lead to restlessness and tachycardia in the infant.

The sympathomimetics formoterol and salmeterol are effective for longer but are less well studied. According to the experience to date, they are scarcely problematic for the breastfed infant. There are no observations available on indacaterol .

The oral or parenteral use of β ₂ -sympathomimetics such as, for instance, bambuterol , clenbuterol and tulobuterol should be reserved for exceptional conditions during breastfeeding.

4.2.3

Inhalable corticosteroids (ICS)

ICS such as budesonide and the fluoridated ICS beclomethasone , fluticasone , mometasone and ciclesonide do not require any limitation of breastfeeding. The best studied is budesonide. The passage into the mother’s milk and the serum concentrations were determined with eight mother–child pairs. The maternal oral dose was 200 or 400 μg 2 × daily, of which the infant received about 0.3%. No budesonide could be detected in the infant’s serum (detection limit 9 mg/L); 1/600 of the maternal plasma levels were considered possible mathematically ( ).