Copy of this information is available as a pdf

https://breastfeeding-and-medication.co.uk/wp-content/uploads/2023/05/travel-sicknes-and-breastfeeding.pdf

As the summer season and travels begin, my mind has turned to travel sickness and breastfeeding. I suffer badly personally!

I hope this helps you enjoy your travels rather than dread them

Causes of travel sickness

Travel sickness or motion sickness happens when the body, the inner ear, and the eyes send conflicting signals to the brain. This most often happens when you are in a car, boat, or airplane, but it may also happen on flight simulators or amusement park rides.

It is more common in children and in women. Sitting in the back of the car can also be a trigger for many people or a on a coach. I personally find the new trains which are faster much harder to deal with as they seem to sway much more.

It is difficult as a breastfeeding mother to deal  with your own travel sickness as well as a baby or children. You may be able to drive rather than be a passenger. If not ,then there are medications which you can take which wont reduce your supply (because only being used short term) or affect your baby. Some temporary drowsiness is possible with any medicine which makes you drowsy.

Symptoms of travel sickness

Symptoms can come on very suddenly but rapidly escalate:

• Nausea and vomiting
• Pale skin
• Cold sweats
• Dizziness
• Headache
• Increased salivation
• Fatigue
• Difficulty concentrating
• Rapid breathing

These are symptoms not dissimilar to panic.

Medication

• If you are breastfeeding and need to care for a baby you  may prefer one that is less likely to cause drowsiness – e.g.  cinnarizine (Stugeron™)
• Hyoscine (Kwells ™, Joy Rides™) is usually regarded as the most effective medicine for motion sickness taken 30-60 minutes before the journey.
• Prochlorperazine (Buccastem™, Stemetil™)
• Cyclizine might be prescribed for you but is no longer available over the counter.
• Hyoscine patch can be prescribed. These are applied behind the ear 5-6 hours before travelling.
• Metoclopramide and domperidone may be useful to slow gastric emptying but are generally not prescribed for travel sickness.
• Homeopathic remedies e.g. Nelson’s Travella has limited research but is not harmful to the breastfed infant if it is a remedy which the mother finds useful.
• Antihistamines which cause drowsiness e.g. promethazine (Phenergan™, chlorpheniramine (Piriton ™) may be useful for children who struggle with travel sickness although it is rare before the age of 2 years.

Acupressure Bands

Some studies suggest that acupressure may help reduce symptoms of motion sickness in the same way as acupuncture. Acupressure bands are available commercially to help prevent motion sickness. Studies suggest these bands may help delay the onset of symptoms.

Traditionally, the acupuncture point known as Pericardium 6 is said to help relieve nausea. It is on the inside of the wrist, about the length of 2 fingernails up the arm from the centre of the wrist crease.

To reduce risk of travel sickness without medication

https://www.nhs.uk/conditions/motion-sickness/

• sit in the front of a car or in the middle of a boat.
• look straight ahead at a fixed point, such as the horizon rather than at a book, phone screen or portable device.
• fresh air e.g.  open a car window
• close your eyes and breathe slowly while focusing on your breathing.
• distract children by talking, listening to music or singing songs.
• break up long journeys to get some fresh air, drink water or take a walk.
• some people recommend ginger, as a tablet, biscuit or tea but if you have had significant sickness in pregnancy this may bring back memories!
• Avoid heavy or fatty meals.

Fear of flying

One of the questions I have had frequently at this time of year has been about supporting the breastfeeding mother who has a fear of flying. I know this feeling myself so can empathise. I have always wanted to keep my headphones on and focus on breathing and listening to my music/relaxation most just when you are coming in to land and are told to take them off. I resort to counting backwards from a thousand.

However, diazepam as one or two low doses can be prescribed during breastfeeding. At worst the baby may temporarily be a little drowsy, but in practice this doesn’t seem to happen ( they are often too busy looking round and being social!)

Don’t forget to pack plastic bags or bowls ( just in case), wipes and cold water if the worst happens.

When I was working as an independent pharmacist prescriber my main role was to look at primary prevention of cardio vascular disease – identifying factors which raised the risk of people to have a heart attack or stroke in the next 10 years. I used an online calculator using various data like BMI, smoking status, blood pressure and cholesterol ( https://qrisk.org/three/). I didnt see many breastfeeding patients and we concentrated on the over 50s. But in the process I learned a lot about managing weight and encouraging a healthy diet and portion size, smoking cessation and control of cholesterol. In many cases we managed to reduce the risk with lifetyle changes.

It seems that mothers may now have their cholesterol measure and advised that it is too high. I had 20 -30 minute appoitments to encourage lifestyle change. This isnt possible for GPs with pressures on appointments so often the mothers are offered medication to reduce cholesterol. Until recently the only drug compatible with breastfeeding was cholestryamine. This is fine if there isnt a history of familial hypercholesterolaemia and a much higher risk of a cardio vascular event.

A colleague pointed me to some data on elactancia which had a very different list of references and information on cholesterol in standard artificial formula. Thus began a journey to this factsheet over the past couple of months. It isnt a recommendation, as there are currently no studies on the use of statins during breastfeeding nor the effect on the baby . However, it looks at an evidence base which can prompt discussion with clinicians. I hope it helps.

My thanks to Sam Morris and Amanda Da Costa for their knowledge and support as pharmacists and breastfeeding helpers on the BfN Drugs in Breastmilk Information Service

See also SPS information April 2023

https://www.sps.nhs.uk/articles/using-lipid-lowering-medicines-during-breast= feeding/

Raised cholesterol and breastfeeding factsheet

Breastfeeding mothers may take mebendazole and continue to breastfeed as normal

Threadworms, also known as pinworms, are tiny parasitic worms that infect the large intestine of humans. Threadworms are a common type of worm infection in the UK, particularly in children under the age of 10. European estimates have suggested that 20 to 30% of pre-school and primary-school-aged children will have threadworm infestation. The worms are white and look like small pieces of thread.

Threadworms spread easily within childcare settings when children scratch their bottoms causing the eggs which have come out of the anus, to collect underneath fingernails. They can then be transferred into the mouth or substances like PlayDough! I know it is a yucky thought bit part of toddler life!

How threadworms spread

Threadworms spread when their eggs are swallowed. They lay eggs around the bottom (anus), which make it itchy. The eggs get stuck on fingers when scratching. They can then pass on to anything touched, including:

• clothes
• toys
• toothbrushes
• kitchen or bathroom surfaces
• bedding
• food
• pets

Eggs can pass to other people when they touch these surfaces and then touch their mouth. They take around 2 weeks to hatch.

Once ingested, larvae emerge from the eggs and mature within 1–2 months into adults in the small intestine. The mature adult female worm migrates through the anus and lays thousands of eggs on the peri-anal skin (typically at night) causing itching. Adult threadworms survive for about 6 weeks and infection is maintained by swallowing fresh eggs.

Complications caused by threadworm include:

• Lack of sleep (due to itching) with subsequent daytime irritability and difficulty in concentrating.
• Bedwetting
• Weight loss or loss of appetite.
• Breakdown and soreness of the skin around the back passage

Treatment (BNF)

• In adults, 100 mg mebendazole (Ovex ™ or Vermox ™) for 1 dose. If reinfection occurs, a second dose may be needed after 2 weeks.
• In children, aged 6 months to 17 years, 100 mg for 1 dose, if reinfection occurs, a second dose may be needed after 2 weeks.

Breastfeeding

• Amount present in milk too small to be harmful but manufacturer advises avoid (BNF).
• Oral bioavailability 2-10%, highly plasma protein bound, half life 2.8-9 hours Considering the poor oral absorption and high protein binding, it is unlikely that mebendazole would be transmitted to the infant in clinically relevant concentrations (Hale Medications and Mothers Milk accessed April 2023)
• Mebendazole is poorly excreted into breastmilk and poorly absorbed orally. Reports on the use of mebendazole during breastfeeding have found no adverse reactions in breastfed infants. (LactMed https://www.ncbi.nlm.nih.gov/books/NBK501340/ accessed April 2023)
• Based on a low oral bioavailability, concentration in the infant’s plasma should be nil or low, except in premature and newborn infants with a increased intestinal absorption capacity. (Elactancia https://www.e-lactancia.org/breastfeeding/mebendazole/product/ accessed April 2023)

Breastfeeding mothers may take the mebendazole and continue to breastfeed as normal

Things to do to stop re-infection

• wash hands and scrub under fingernails – particularly before eating, after using the toilet or changing nappies
• encourage children to wash hands regularly
• bathe or shower every morning
• rinse toothbrushes before using them
• keep fingernails short
• wash sleepwear, sheets, towels and soft toys (at a hot temperature)
• disinfect kitchen and bathroom surfaces
• vacuum and dust with a damp cloth
• make sure children wear underwear at night – change it in the morning

Head lice are a common problem with older children. Scratching the head is normally the first sign but eggs may be seen behind the ears and nape of the neck. The breastfeeding mother may need to apply preparations to her children and usually herself.  Head lice are spread by head-to-head contact common between all mums and children as well as siblings and friends, not forgetting grandparents. Headlice are not a sign of poor hygiene and in fact they prefer clean hair.

Medicated lotions should not be used unless live lice are detected after 17 days regular combing.

Prevention is best achieved by regular combing with a fine-toothed comb. For further information see https://www.nhs.uk/conditions/head-lice-and-nits/ and https://www.chc.org/for-parents-2/ for a video.

Head lice may be mechanically removed by meticulous combing of wet, well-conditioned hair with a fine-toothed detection comb. Combing needs to be undertaken for at least 30 minutes at four-day intervals for a minimum of two weeks. Conditioner facilitates combing particularly of long hair. If there are still live headlice then suitable chemical treatment should be used.

Treatments with lotions or liquids are preferable to shampoos which are diluted below an effective therapeutic concentration. Aqueous solutions are recommended for children with eczema or asthma. Rotation of treatments is no longer recommended. A mosaic approach is considered advisable however, whereby the child or adult is treated with a different chemical at each infestation or if a treatment fails.

Absorption of the products through the skin for sufficient quantities to pass into breastmilk is unlikely although the patient information leaflet in the box may suggest otherwise.  If a breastfeeding mother has to treat several children’s heads it may be sensible to use gloves to protect her hands and to ensure the room is well ventilated.

There are a variety of products available to treat head lice E.g., Vamousse™, Lyclear™, Full Marks™, Hedrin™

Treatments not recommended as evidence suggests that they are ineffective (https://www.nhs.uk/conditions/head-lice-and-nits/) :

• products containing permethrin
• head lice “repellents”
• electric combs for head lice
• tree and plant oil treatments, such as tea tree oil, eucalyptus oil and lavender oil herbal remedies

Following the recommendation by NICE (March 2023) I looked at the evidence on semaglutide and breastfeeding. There are no current published reports, only theory from pharmacokietics.

It seems that there are no supplies just now either as I understand.

I have found the ZOE podcast interesting (no financial involvement) https://link.chtbl.com/s9cwxMzY

And Margaret MCartnetny view in the BMJ https://www.bmj.com/content/380/bmj.p624.full

Pdf of factsheet :

https://breastfeeding-and-medication.co.uk/wp-content/uploads/2023/03/semaglutide-and-breastfeeding-.pdf

Semaglutide binds to, and activates, the GLP-1 (glucagon-like peptide-1) receptor to increase insulin secretion, suppress glucagon secretion, and slow gastric emptying.

Semaglutide is used to treat Type 2 diabetes mellitus as monotherapy (if metformin inappropriate), or in combination with other antidiabetic drugs (including insulin) if existing treatment fails to achieve adequate glycaemic control. In March 2023 it was recommended for the treatment of obesity in specific circumstances.

Use in obesity.

Semaglutide (Wegovy™) was recommended by the National Institute for Health and Care Excellence (NICE) to treat thousands of people with obesity in England (March 2023). Semaglutide will be allowed to be prescribed to help people lose weight as part of their treatment in an NHS specialist weight management service. The drug works by suppressing appetite by mimicking the hormone glucagon-like peptide-1 (GLP-1), which is released after eating. It is injected once a week by patients. NICE first recommended the drug in draft guidance 2022, after a clinical trial of just under 2000 volunteers found that people lost on average 12% more weight with semaglutide alongside supervised weight loss coaching (BMJ 2023;380:556).

Guidelines for use in obesity

Semaglutide is recommended as an option for weight management, including weight loss and weight maintenance, alongside a reduced-calorie diet and increased physical activity in adults, only if:

• it is used for a maximum of 2 years, and within a specialist weight management service providing multidisciplinary management of overweight or obesity (including but not limited to tiers 3 and 4), and
• they have at least 1 weight-related comorbidity and:
• a body mass index (BMI) of at least 35.0 kg/m2, or a BMI of 30.0 kg/m2 to 34.9 kg/m2 and meet the criteria for referral to specialist weight management services in NICE’s guideline on obesity: identification, assessment and management.

Consideration should be made to stop semaglutide if less than 5% of the initial weight has been lost after 6 months of treatment. (https://www.nice.org.uk/guidance/TA875/chapter/1-Recommendations)

Currently Wegovy is not commercially available. Ozempic is available but is not licensed for weight management but only treatment of diabetes.

Dose

By subcutaneous injection( Ozempic™ ): Initially 0.25 mg once weekly for 4 weeks, then increased to 0.5 mg once weekly for at least 4 weeks, then increased if necessary to 1 mg once weekly.

By mouth (Rybelsus™): Initially 3 mg once daily for 1 month, then increased to 7 mg once daily for at least 1 month, then increased if necessary to 14 mg once daily, dose to be taken on an empty stomach, one 14 mg tablet should be used to achieve a 14 mg dose; use of two 7 mg tablets to achieve a 14 mg dose has not been studied and is therefore not recommended; maximum 14 mg per day.

By subcutaneous injection (Wegovy™): initially 0.25 mg once a week and increased every 4 weeks until the full dose of 2.4 mg is reached.

Compatibility with breastfeeding

• It is currently not known if semaglutide is excreted in human milk.  The molecular weight of this medication  means that it would have great difficulty entering breast milk. It is described as having oral bioavailability < 1% although an oral preparation exists. In consequence very little of this medication would be absorbed by the infant orally even  if found in breast milk. The risk of this in a breastfed infant would be expected to be very low (Hale and Krutsch).
• Manufacturer advises avoid stating that it is present in milk in animal studies. so its use in a lactating mother would be outside of the product licence (BNF)
• No information is available on the clinical use of semaglutide during breastfeeding. Because semaglutide is a peptide molecule with a molecular weight of 4113 daltons and is over 99% protein bound, the amount in milk is likely to be very low. Absorption by the infant is unlikely because the drug is probably destroyed in the infant’s gastrointestinal tract. Until more data become available, semaglutide should be used with caution during breastfeeding, especially while nursing a new-born or preterm infant. (https://www.ncbi.nlm.nih.gov/books/NBK500980/)
• Elactancia cites semaglutide as of very low risk in lactation (https://www.e-lactancia.org/breastfeeding/semaglutide/product/ ).  Its high molecular weight and high fixation to plasma proteins make it very unlikely to pass into mothers’ milk in a clinically significant quantity. (Serrano 2015). In addition, due to its protein nature it is inactivated in the gastrointestinal tract, not being absorbed (practically null oral bioavailability), which hinders or prevents the passage into plasma of the infant from ingested breast milk (Serrano 2015), except in premature infants and during the immediate neonatal period, in which there may be greater intestinal permeability.

Common or very common side effects

Appetite decreased; burping; cholelithiasis; constipation; diarrhoea; dizziness; fatigue; gastrointestinal discomfort; gastrointestinal disorders; hypoglycaemia (in combination with insulin or sulfonylurea); nausea; vomiting; weight decreased (BNF).

Monitoring of nursling for side effects

Although adverse effects have not been noted the baby should be monitored for decreased appetite, abdominal distension, GERD, constipation, diarrhoea. (Hale and Krutsch)

Can my GP prescribe Wegovy™  in the UK for weight loss?

Semaglutide can only be prescribed as part of a specialist (tertiary) weight management service with multidisciplinary input and for a maximum of two years. https://www.nice.org.uk/guidance/ta875/chapter/1-Recommendations

Conception and contraception

Manufacturer advises women of childbearing potential should use effective contraception during and for at least two months after stopping treatment.

References

Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501922/

Hale TW and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (online access HalesMeds.com January 2023)

Joint Formulary Committee (2022) British National Formulary. [Online]. London: British Medical Association and  Royal Pharmaceutical Society of Great Britain. Available at: Medicines Complete Database, [Accessed January 2023].

 Elactancia Is it compatible with breastfeeding? https://www.e-lactancia.org/

Serrano Aguayo P, García de Quirós Muñoz JM, Bretón Lesmes I, Cózar León MV. Tratamiento de enfermedades endocrinológicas durante la lactancia. [Endocrinologic diseases management during breastfeeding.] Med Clin (Barc). 2015 Jan 20;144(2):73-9.

Breastfeeding-specific multi vitamin supplements are expensive and many mothers want to purchase standard multivitamin and mineral supplements. The standard products such as Sanatogen™ and Centrium™ are suitable for use. It is important not to take products which claim to be high dose and where the recommended daily amount is reported as in excess of 100% on the label.

The only vitamins needed by breastfeeding mothers are vitamin D 10 mcg/day and folic acid 400mcg/day if no active contraception is being used. Normal diets should provide everything your body needs. Remember babies need vitamin D supplements too according to UK recommendations

However, we do know that as a new mum finding time to eat properly can be a challenge and a multivitamin is a safety net.

AVOID dose of vitamin A above 700-800 mcg/day and vitamin B6 above 20-50 mg/day. Iodine can concentrate in breastmilk so do not take levels in excess of 100% RDA.

Omega fatty acids are compatible with breastfeeding

There are no studies on the safety of high dose intra-venous (IV) vitamin drips in breastfeeding mothers. These are purported to cure hangovers, help fight exhaustion, have anti-ageing benefits and to boost the immune system. These claims lack scientific evidence of benefit.

In the absence of a diagnosed vitamin deficiency a standard multivitamin and mineral preparation or a supplement developed for pregnant and breastfeeding mothers, containing vitamin D and folic acid, as above should supply all nutritional needs alongside a healthy diet.

See also factsheet on high dose vitamin D supplements and breastfeeding

High Dose Vitamin D Supplements and Breastfeeding

https://breastfeeding-and-medication.co.uk/fact-sheet/high-dose-vitamin-d-supplements-and-breastfeeding

After some discussions with the Thyroid Trust I have put this information together

PDF of this factsheet available here https://breastfeeding-and-medication.co.uk/wp-content/uploads/2023/02/thyroid-and-breastfeeding-.pdf

Underactive Thyroid and Breastfeeding (Hypothyroid)

“Many medical professionals seem unaware of how important adjusting meds during and post pregnancy is and that it can influence breastfeeding as well”

Description

An underactive thyroid gland is where the thyroid gland does not produce enough hormones. Common signs of an underactive thyroid are :

• tiredness,
• weight gain
• feeling depressed
• being sensitive to the cold,
• slowed thought processes,
• muscle pains
• dry skin and brittle hair.

Most people presenting with symptoms of depression will be asked to have a blood test before medical treatment. Similarly although it is normal to lose the thicker hair which is enjoyed in pregnancy, significant hair loss should also be considered a possible symptom.

Hypothyroidism is identified by blood tests which are conducted regularly until they are within stabilised levels. Blood levels are ideally taken routinely after delivery and especially  if the mother reports a poor milk supply. Levels at the low end of normal are frequently associated with low prolactin and poor breastmilk supply.

Hypothyroidism is ten times more common in women than it is in men. In the UK, around 1-2 in 100 people have hypothyroidism. It most commonly develops in adult women and becomes more common with increasing age. However, it can occur at any age and can affect anyone.

Treatment

Levothyroxine is secreted in extremely low levels into breastmilk, if at all (Bennett 1988; Oberkotter 1983; Sato 1979). It is highly bound to proteins in the maternal plasma, so little is free to pass into breastmilk.

The level to which the baby will be exposed via breastmilk is virtually undetectable. Levels secreted into milk are too low to influence tests for neonatal hypothyroidism according to Martindale (2017). There is no need to routinely test breastfed babies unless there They should be swallowed with water on an empty stomach, with no food for 30 minutes afterwards.

References

• Bennett PN (ed.), Drugs and Human Lactation, Amsterdam: Elsevier, 1988.
• Brown A Jones W A guide to breastfeeding for the medical professional Routledge 2019
• Drugs and Lactation Database (LactMed®) https://www.ncbi.nlm.nih.gov/books/NBK501003/
• E lactancia https://www.e-lactancia.org/breastfeeding/levothyroxine/product/
• Jones W Breastfeeding and Medication Routledge 2018
• Martindale The Complete Drug Reference. Pharmaceutical Press 2017
• Oberkotter LV, Tenore A, Separation and radioimmunoassay of T3 and T4 in human breastmilk, Horm Res, 1983;17:11–18.
• Sato T, Suzuki Y, Presence of triiodothyronine, no detectable thyroxine and reverse triiodothyronine in human milk, Endocrinol Jpn, 1979;26:507–13.

Overactive thyroid and breastfeeding  (Hyperthyroid disease)

“I was told to stop breast feeding immediately after being put on carbimazole for an overactive thyroid. I’m still so angry that it wasn’t necessary”

Description

Hyperthyroidism has a variety of causes. It is ten times more common in women than men, and typically begins between 20 and 40 years of age It is often diagnosed post-partum in breastfeeding women.

Symptoms include:

• nervousness,
• anxiety and irritability,
• mood swings,
• difficulty sleeping,
• persistent tiredness and weakness,
• sensitivity to heat, palpitations,
• weight loss (despite increased appetite),

Three in every 4 cases of hyperthyroid are caused by Graves’ disease, an auto-immune condition.  Less commonly it develops because of nodules on the thyroid gland.

Treatment

Carbimazole – is a pro-drug that is bioactivated to methimazole. It produces sub-clinical levels in infants exposed to less than 30 mg a day through their mother’s breastmilk (Rylance 1987). Carbimazole has a relative infant dose of 2.3% – 5.3% (Hale) where levels less than 10% are regarded as compatible with breastfeeding.

In a study of 5 five lactating women receiving 40 mg/d, the mean concentration of methimazole in milk measured by .Johansen was 182 µg/L, with a mean milk/serum ratio of 0.98.  The mean total amount of methimazole excreted in milk over 8 h was 34 µg. The limited data suggest that the transfer of carbimazole is too low to affect thyroid function in breastfeeding infants.

If the drug is used at a dose above 30mg, monitoring of the infant’s thyroid function periodically might be advisable. Otherwise monitoring would only be necessary if the baby exhibits clinical symptoms.

In February 2019 the MHRA issued a notice that “ Carbimazole is associated with an increased risk of congenital malformations, especially when administered in the first trimester of pregnancy and at high doses. Women of childbearing potential should use effective contraception during treatment with carbimazole.”  https://breastfeeding-and-medication.co.uk/fact-sheet/carbimazole-in-women-of-childbearing-age

References

• Brown A Jones W A guide to breastfeeding for the medical professional Routledge 2019
• Drugs and Lactation Database (LactMed®) https://www.ncbi.nlm.nih.gov/books/NBK501759/
• E lactancia https://www.e-lactancia.org/breastfeeding/carbimazole/product/
• Hale TW  and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (also available as https://www.halesmeds.com/ by subscription). Springer Pub
• Jones W Breastfeeding and Medication Routledge 2018
• MHRA Carbimazole: increased risk of congenital malformations; strengthened advice on contraception www.gov.uk/drug-safety-update/carbimazole-increased-risk-of-congenital-malformations-strengthened-advice-on-contraception
• Rylance GW, Woods CG, Donnelly MC, Oliver JS, Alexander WD, Carbimazole and breastfeeding, The Lancet, 1987;1(8538):928

Propylthiouracil has been the drug of choice in a breastfeeding mother as the transfer into breastmilk is lower than that with carbimazole. In 2009 the US Food and Drug Administration (FDA) in the USA alerted practitioners to an increased risk of hepatotoxicity (liver toxicity)  with PTU use and recommended that all patients should be observed and monitored for signs of liver disease, particularly during the first six months of treatment. Signs of liver damage, which should be reported to the prescriber immediately are anorexia, nausea, vomiting, fatigue, abdominal pain, jaundice, dark urine, or pruritus (BNF). Propylthiouracil crosses the placenta and in high doses may cause foetal goitre and hypothyroidism.

Only small amounts of propylthiouracil are secreted into breastmilk and reports suggest that levels are too low to produce side effects (Cooper 1987). Propylthiouracil is extensively plasma protein bound (80%) and has an oral bioavailability of 50–75% which is low. At doses of 400 mg, a study of nine women and their babies showed levels of PTU in milk reached only 0.7 µg per millilitre (Kampmann 1980). One of the babies was studied for five months during which the mother received 200–300 mg of PTU daily. There were no changes to the infant’s thyroid functions. Momotani’s (2000) study of 11 babies has shown that up to 750 mg produced no changes in babies monitored up until 11 months of age. Monitoring is recommended as a precaution if clinical symptoms are identified in the baby.

References

• Cooper DS, Antithyroid drugs: to breastfeed or not to breastfeed, Am J Obstet Gynecol, 1987;157:234–5.
• Drugs and Lactation Database (LactMed®) https://www.ncbi.nlm.nih.gov/books/NBK501084/
• E lactancia https://www.e-lactancia.org/breastfeeding/propylthiouracil-ptu/product/
• FDA Alert 2009, Information for Healthcare Professionals – Propylthiouracil-Induced Liver Failure (www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm162701.htme).
• Hale TW  and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (also available as https://www.halesmeds.com/ by subscription). Springer Pub
• Jones W Breastfeeding and Medication Routledge 2018
• Kampmann JP, Johansen K, Hansen JM, Helweg J, Propylthiouracil in human milk, The Lancet,1980;1(8171):736–7.
• Momotani N, Yamashita R, Makino F, Noh JY, Ishikawa N, Ito K, Thyroid function in wholly breastfeeding infants whose mothers take high doses of propylthiouracil, Clin Endocrinol (Oxf), 2000;53(2):177–81.

Propranolol is often used to relieve symptoms of an over active thyroid. It is 90% plasma protein bound, the milk plasma ratio and it is only 30% orally bio available. Its relative infant dose is 0.3-0.5% so virtually none passes into milk and breastfeeding can continue as normal. This has been confirmed in several studies.

References

• Bauer JH, Pape B, Zajicek J, Groshong T. Propranolol in human plasma and breast milk. Am J Cardiol. 1979; 43(4):860-862.
• Brown A Jones W A guide to breastfeeding for the medical professional Routledge 2019
• Drugs and Lactation Database (LactMed®) https://www.ncbi.nlm.nih.gov/books/NBK501162/
• Elactancia https://www.e-lactancia.org/breastfeeding/propranolol/product/
• Hale TW  and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (also available as https://www.halesmeds.com/ by subscription). Springer Pub
• Jones W Breastfeeding and Medication Routledge 2018
• Lewis AM, Patel L, Johnston A, Turner P. Mexiletine in human blood and breast milk. Postgrad Med J. 1981 Sep;57(671):546-547.
• Smith MT, Livingstone I, Hooper WD, Eadie MJ, Triggs EJ. Propranolol, propranolol glucuronide, and naphthoxylactic acid in breast milk and plasma. Ther Drug Monit. 1983; 5(1):87-93.
• Taylor EA, Turner P. Anti-hypertensive therapy with propranolol during pregnancy and lactation. Postgrad Med J. 1981;57(669):427-430.

Radiotherapy involving ingestion of iodine is not suitable during breastfeeding as iodine concentrates in breastmilk and lasts for some time so would mean stopping breastfeeding