Wednesday, March 09, 2022

Breastfeeding and Drugs

This post is about one of an important topic Breastfeeding and Drugs. The choice of safe drugs during pregnancy and breastfeeding is paramount for an obstetrician. The safety profile for mother as well as infant is to be kept in mind. This post covers analgesics, antibiotics, antidepressants and drugs used for complex medical conditions. The points have been extracted from a TOG article which was published in April 2021. I have compiled the information in a tabulated form which will be helpful in quick revision for the exam. 


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Introduction

  Most drugs can be take safely by lactating mothers

  Medications use during breastfeeding shortens the duration of breastfeeding mainly due to maternal fear of harming the baby

 

Common drugs used in lactation period




















Analgesics

  In postnatal period — analgesia is needed routinely most often after CS, AVB & perineal tear repair



Analgesics

Pharmacokinetics

Drug levels — in mother / infant 

Effects on infant

Effect on lactation & breast milk

Paracetamol

    Non-opioid

    No anti-inflammatory action

    Oral absorption rates depend on gastric emptying 

    Peak in breast milk 1-2 hr after

    Infants exposed to 1%-3.5% of maternal-adjusted dose

No adverse affects

 

Ibuprofen

    NSAID 2 arylpropionic acid (2-APA) class

    Oral - rapid & complete absorption 

    Short half-life 

    Low risk of accumulation

    Undetectable in breast milk

No adverse affects

 

Codeine

    Very weak analgesic activity

    Analgesic activity provided by its metabolites

Metabolised to

    Morphine, norcodeine & codein-6-glucuronide via CYP2D6

    Morphine-6-glucuronide via UGT2B7

 

    1% of maternal-adjusted dose received by fully breastfed infant

    Plasma clearance prolonged in newborn infants

    Morphine:codeine ratio higher in infant serum

Contraindicated by MHRA to used during lactation

Increased serum prolactin — does not affect ability to breastfeed in established lactation

Aspirin

Rapidly metabolised to salicylic acid

Excreted into breast milk at high levels

    Metabolic acidosis may occur

    Thrombocytopenia, fever & petechia 

No effect

Tramadol

    Centrally acting

    Structurally related to codeine & morphine

    Agonist at mu opioid receptors

    Inhibits re-uptake of serotonin & noradrenaline

Low excretion into breast milk

Limited

Increased serum prolactin — does not affect ability to breastfeed in established lactation

Morphine

    Metabolised to inactive morphine-3-gluoronide (60%) & active morphine-6-glucoronide (10%) within 15-20 min of IM or SC & within 30-90 min or oral

    Much lower peak levels after oral use

    Prolonged plasma clearance in very young infants

    Clearance approach adult level at 2 months of age

 

Unlikely to be harmful

Delayed lactogenesis

 

Antibiotics



Antibiotics

Pharmacokinetics

Drug levels — in mother / infant 

Effects on infant

Effect on lactation & breast milk

Co-amoxiclave

Î’-lactam inhibits peptidoglycan synthesis 

0.25 - 0.5% of standard infant dose 

    Side effects uncommon

    Restlessness, diarrhoea, rash

Not significant

Flucloxacillin

Î’-lactam specially for G+ve organisms 

Low

Ocasional diarrea & thrush

Safe to use

Metronidazole

    Bactericidal 

    Inhibits nucleic acid synthesis in bacterial cells

    Well absorbed orally

    >90% bioavailability 

    Absorption unaffected by infection

    After topical — plasma levels 1% of that after 250 mg oral dose

    Use only water or gel-based for breast 

    Well distributed in breast milk 

    Infants exposed to less than standard paediatric doses

    Well tolerated

Candida infections & diarrhoea

    Altered taste of breast milk

    No negative impact on ability to breastfeed

Ciprofloxacin

    Fluoroquinolone 

    Inhibits DNA gyros & topoisomerase IV

    Negligible risk after topic use

    After oral infant would receive max of 0.57 mg daily

No effect

 

Tetracyclines

    Protein synthesis inhibitor 

    Biostatic 

    Inhibit translation by binding to 30S ribosomal subunit

 

Avg peak & trough levels approx 6% of maternal weight-adjusted dose

Short-term use unlikely to be harmful

 

Nitrofurantoin

    Contraindicated <1 month or in G6PD deficiency 

Low

    Do not use <8 days  after delivery or in G6PD deficiency 

 

Vancomycine & Teicoplanin

    Mainstay t/m for MRSA

    Poorly absorbed orally 

Unlikely to reach infant

 

 

 

Anxiety & Depression









 


  Antidepressants during breastfeeding depend on the drugs used antenatally

  Abrupt cessation or change of drugs not recommended

  If antidepressants taken 

  All through pregnancy — 37% less likely to breastfeed

  From 3rd trimester — 75% less likely to breastfeed

  Must support & reassure the patient 

 

Drugs

Drug levels — in mother / infant

Effect on lactation & breast milk

SSRI

Sertaline  — SSRI of choice

    Low levels in breast mil 

    Not detected in infant serum

If SSRI used during pregnancy & lactation, mother may struggle with breastfeeding

Fluoxetine — higher average level in breast milk

    Can cause colic & drowsiness 

    No long term adverse developmental outcomes

    Do not stop if needed by mother

    Monitor infants 

TCA

    Low levels in breast milk

    May cause drowsiness & sedation

 

Others

Venlafaxine — relatively higher dose transferred to infants

 

 

High Blood Pressure



VTE and Breastfeeding

 

Drugs

Drug levels — in mother / infant

Warfarin

    Very low levels in breast milk

    No effect on vitamin K-dependent clotting factors

    No special precautions required

LMWH

    Not excreted into breast milk or absorbed by an infant

Direct oral anticoagulants 

    Not recommended as first-line t/m in pregnancy / lactation

    Paucity of safety data

 

Complex Medical Problems

 

Condition/ Drugs

Mother / Infant

Asthma

Beta-2 Agonists & Steroid Inhalers —Safe

Montelukast — low levels excreted & can be used in children as young as 6 months

High-dose Steroids — can continue breastfeeding with short courses

Steroids

Prednisolone — safe up to 40 mg/day

    Poorly excreted into breast milk 

 

Monoclonal antibodies

    Paucity of safety data

    Excretion into breast milk minimal 

    Absorption minimal

Adalimumab / Inflximab — no adverse effects, be cautious 

Antiepileptic drugs

    Some drugs (e.g. phenytoin, carbamazepine) enhance metabolism of other drugs, whereas other (e.g. valproic acid) slow metabolism

Levetiracetam — low levels excreted in breast milk, safe to use, may reduce breast milk supply in some

Lamotrigine — encourage to breast feed. Need to monitor serum levels in infant & adjust the dose

Sodium valproate — reassuring safety profile, can be used

 

Contraception and Breastfeeding

Emergency Contraception

  No special precautions

  If used Ulipristal Acetate (ellaOne) — avoid breastfeeding for 1 week

Key messages 

  Lactational amenorrhea can be up to 98% effective if following criteria met

   Fully breastfeeding, infant age less than 6 months, woman amenorrhic

  If not breastfeeding — contraception required from 21 day postpartum

  Safe to use in breastfeeding women — POP, Injectables

  From 6 wks breastfeeding women can use — COCP, Patch 

Cu-IUCD & LNG-IUS can be fitted within 48 hrs of delivery


You may be interested in:

MRCOG Revision Courses

TOGs Topics List

All GTGs

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