Drugs in pregnancy and breastfeeding Flashcards
(23 cards)
Stages of Pregnancy
First trimester:
Congenital malformations
Greatest risk from 3rd to 11th week of pregnancy
Second and third trimester
Affect growth or functional development
Toxic effect on foetal tissues
Before term or during labour
Adverse effect on labour
Adverse effect on neonate after delivery
General Pre-conception advice - AVOID
Recreational drugs
‘natural’ or herbal remedies
Alcohol
Smoking
Vitamin A products
Minimise caffeine consumption
Some foods-see Dr Pufal’s lecture
Some drugs in both men and women
General conception advice - RECOMMEND
Folic acid- 400micrograms daily (5mg if assessed as high risk of NTD)
Vitamin D 10 micrograms daily
Drugs in Pregnancy - what was withdrawn from uk marker
Thalidomide withdrawn from UK market in 1961
Consequently realised that drugs have the potential to cross the placenta
Specialist Counselling before conception recommended for women requiring drug treatment for example
Epilepsy
Hypertension
Diabetes
Mental Health
Valproate containing medicines
Sodium valproate and valproic acid
Changes in Human Medicines Regulations 2023 (Oct 23)
Pharmacists must dispense all licensed medicines containing valproate in the manufacturer’s original full pack
Pharmacists should round up or down the quantity prescribed
Valproate-containing medicines must not be re-packaged in plain dispensing package
Based on individual risk assessment which assesses the needs of a patient, an exception can be made (e.g. in a monitored dosage system) providing processes are in place to ensure a PIL is supplied
MHRA update advises:
on sodium valproate
‘Valproate medicines must no longer be used in women or girls of childbearing potential unless a Pregnancy Prevention Programme is in place’
Under the Pregnancy Prevention Programme healthcare professionals are responsible for prescribing valproate safely
Role of GPs on sodium valproate
GPs must-
identify and review all female patients on valproate, including when it is used outside the licensed indications (off-label use) - for example migraine prophylaxis
provide patient information materials every time the patients attend their appointments or receive their medicines
check they have been reviewed by a specialist in the last year and are prescribed appropriate contraception
Role of Specialists on sodium valproate
Specialists must
book review appointments at least annually with women and girls under the Pregnancy Prevention Programme
re-evaluate treatment as necessary
explain clearly the conditions as outlined in the supporting materials
complete and sign the valproate annual risk acknowledgement form
provide copies of the form to the patient, carer or responsible person and send a copy to the GP
Role of Pharmacists in sodium valproate
Pharmacists must
ensure valproate medicines dispensed to women and girls of childbearing potential have a warning label
discuss risks in pregnancy with female patients each time valproate medicines are dispensed
make sure patients have the valproate patient guide and have seen their GP or specialist to discuss their treatment and the need for contraception
Some drugs may affect sperm
Azathioprine: due to anti-metabolite effects concerns that use could result in genetic abnormalities in sperm and disorders in subsequent offspring
Griseofulvin: men should avoid fathering a child during and for at least 6 months after administration
Methotrexate: men should avoid fathering a child during and for at least 6 months after administration (6 month is 2 sperm cycles)
Post-conception advice
Avoid drugs where ever possible- attempt non-drug treatments first
Avoid all drugs in first trimester when ever possible
Give at lowest effective dose for shortest period of time
Select drugs with established safety profile
Avoid drugs that have not been used extensively in pregnant women
Medicines in breastfeeding
Most medicines will be unlicensed for use in a breastfeeding mother – implications for prescriber
The female breast
The breast is composed of lobes containing glandular tissue and fat.
At the end of pregnancy the hormone prolactin is produced and this stimulates the glandular tissue to lactate
Further stimulation occurs on suckling (x100) and the milk is transported to the ducts
Promoting or reducing lactation
Suckling is the strongest stimulus; if milk is not removed lactation is supressed by pressure in the capilliaries
Suckling stimulates neural pathways to produce prolactin and oxytocin.
As lactation progresses the suckling response diminishes and milk removal becomes the bigger stimulus
Failed lactation
Rare – but commonly perceived
Can be caused by nicotine, retained placental fragments, obesity, bulimia, prolonged stress
Galactagogues should only be used after thorough evaluation, increased frequency of feeding, checking attachment, expression have failed
No licensed treatments in UK – use domperidone 10-20mg three to four times a day. A dopamine antagonist enhances prolactin production
Suppression of lactation
Bromocriptine and cabergoline are both licensed but NOT recommended for routine use for suppression of symptoms of post-partum pain or engorgement
If a dopamine receptor antagonist is used then cabergoline is preferred; 1mg as single dose post-partum or for established lactation 250micrograms bd for 2 days
So – how much of Mum’s medicines reach her milk? - what does it depend on
It depends on
Blood level of medicine in the mother
Amount of drug that enters the milk - depends on the characteristics of the medicine; ionisation, solubility of drug in fatty material or aqueous material, half life of drug, protein binding
Relative concentrations (passive diffusion)
Amount of feed taken by the baby
General advice to mothers …
Breast milk is the best form of nutrition for a baby
Protects babies from infection and atopy
Cheaper than bottles
May protect mother against cancer, weight loss for mother
Mothers are encouraged to feed for at least 6 months (although <1:100 achieve this)
Almost inevitable that mothers will expose baby to some medicines via feeding
New babies and maternal medicines
Once the baby is born it must rely on its own excretory systems to eliminate drugs
Drug clearance values are substantially less in neonates and especially so in premature babies
Beware of drugs with long half lives as accumulation may occur (e.g. antidepressants)
The older a baby is then the less risk of effects from drugs taken by its mother
Warning signs of problems in a baby…
Any unexpected or changes in behaviour
Floppy baby
Irritable baby
Prolonged crying
Prolonged sleeping
Tremor
Feeding problems
Essential questions to ask if faced with a query
Essential questions to ask if faced with a query
Has mum already taken medicine?
Indication, dose, route, frequency and duration?
Prescribed or self-management?
Any other medicines?
Age of baby, full term or prem, healthy?
How often feeding?
Mixed bottle and breast or all breastfed?
General Advice
Avoid unnecessary medicines by assessing risk: benefit for mother and baby
Use lowest effective dose for the shortest period of time
Take special care with premature babies (and the very young)
Check if the medicine is licensed for / or used in babies – if so then there is unlikely to be a problem
Avoid new medicines – no data
Avoid long acting medicines – risk of accumulation
Time drugs to be taken after feeding and avoid feeding when levels are highest
Monitor baby for any adverse effects
