Pharmacology

Question 1

Are many drugs licensed for pregnancy

Answer 1

NO
Little evidence for almost every drug
Therefore most are prescribed off license

Question 2

What are the alternative to prescribing in pregnancy

Answer 2

Consider non-drug alternatives

e.g. CBT for depression or physio instead of painkillers

Question 3

What are some general principles for prescribing in pregnancy

Answer 3

Lowest effective dose for shortest period
If benefit outweighs risk, prescribe
Older drugs have better safety records

Question 4

Which drugs can cross the placenta

Answer 4

Majority can
small lipid soluble drugs cross fastest
Except large molecular weight drugs like heparin

Question 5

How can morning sickness affect medication

Answer 5

Absorption may be reduced

Particularly in Hyperemesis Gravidarum

Question 6

What is the effect of pregnancy on renal excretion

Answer 6

Increased GFR early on in pregnancy – renally excreted drugs tend to be excreted even more.
Eliminated faster

Question 7

Which drugs may pregnant women be more sensitive to

Answer 7

Hypertensive agents

Can lead to hypotension - particularly in the 2nd trimester

Question 8

What medications should be started before pregnancy

Answer 8

Folic acid 400mcg daily for 3 months prior and first 3 months of pregnancy
This is to prevent neural tube defects

Question 9

What is the period of greatest teratogenic risk

Answer 9

4th -11th week is the critical period

Avoid drugs if at all possible unless maternal benefit outweighs risk to foetus

Question 10

List common drugs which are teratogenic

Answer 10

ACE inhibitors/ARB		
Androgens			
Antiepileptics			
Cytotoxics			 
Lithium				 
Methotrexate			
Retinoids	
Warfarin

Question 11

What do common anti-epileptics do to a foetus

Answer 11

Cardiac, facial, limb, neural tube defects

Sodium valproate and phenytoin should be avoided

Question 12

What does lithium do to a foetus

Answer 12

Cardiovascular defects

Question 13

What effects can drugs have in the 2nd trimester

Answer 13

Can get intellectual impairment or behavioural abnormalities

It is the functional development that happens at this stage

Question 14

What is the risk of giving non-steroidal around term

Answer 14

Can cause premature closure of DA

Question 15

What effect do opiates have on a term baby

Answer 15

Opiates can cause respiratory depression and withdrawal syndrome later on

Question 16

Which drugs can cause withdrawal syndromes in a new-born

Answer 16

Opiates

SSRIs

Question 17

What happens to compliance in pregnancy

Answer 17

Often becomes poor as women stop taking it out of fear

Ideally discuss medication prior to conception so that its all safe and sorted

Question 18

What are the risks of having seizures in pregnancy

Answer 18

Frequent seizures during pregnancy are associated with lower verbal IQ in child, hypoxia, bradycardia, antenatal death, maternal death

Therefore epileptics need to stay on some form of treatment

Question 19

How much folic acid should be taken by a woman on anti-epileptics

Answer 19

5mg daily

Question 20

What are the risks of uncontrolled diabetes in pregnancy

Answer 20

increases risk of congenital malformations and intra-uterine death

Question 21

What diabetes drugs should be avoided in pregnancy

Answer 21

Sulfonylureas not safe

Convert patients to insulin

Question 22

Which hypertension drugs should be used in pregnancy

Answer 22

If need to treat, use one of Labetalol or Methyldopa

Avoid ACE inhibitors / ARB

Question 23

What naturally happens to BP in the second trimester

Answer 23

It falls

Question 24

What is the safest drug to use to treat N and V in pregnancy

Answer 24

cyclizine

Question 25

What should you use to treat UTIs in pregnancy

Answer 25

Nitrofurantoin, cefalexin, (3rd trimester – trimethoprim) More prone to UTIs in pregnancy.

Question 26

By how much does pregnancy increase the risk of VTE

Answer 26

10x

Question 27

What is the leading cause of maternal death during pregnancy

Answer 27

VTE

Question 28

Should pregnant women get VTE prophylaxis

Answer 28

YES - if high risk | Give them LMWH

Question 29

How do you treat VTE in pregnancy

Answer 29

Treated with LMWH Avoid warfarin in early pregnancy - teratogenic Avoid in late pregnancy also - haemorrhage

Question 30

Can drugs get into breastmilk

Answer 30

Most do - especially small, fat soluble ones | Few enter in sufficient quantities to cause a problem

Question 31

Which drugs should be avoided in breastfeeding as they accumulate

Answer 31

``` Phenobarbitone Amiodarone Cytotoxics Benzos Bromocriptine ```

Question 32

Which drugs would be used to manage hyperemesis

Answer 32

Anti-emetics like cyclizine or prochlorperazine Ondasentron is very effective but not as much data so 2nd line only Would use thiamine alongside (usually for 1 week) Put up to 5mg folic acid Omeprazole to protect stomach Fragmin to reduce clot risk

Question 33

What risk does ondansetron (anti-emetic) pose in pregnancy

Answer 33

Comes with a small risk of cleft palate in the foetus | Only used if nothing else works and benefit to mum outweighs cleft risk

Question 34

If a woman is on steroids throughout pregnancy, what precaution must be taken in labour and post-natally

Answer 34

Their natural stress hormone response will be suppressed by steroid treatment so they will need IV steroids in labour Would then need to wean them off after delivery

Question 35

Which analgesics can be given in pregnancy

Answer 35

Paracetamol Codeine (oral) Stronger opiates such as morphine (ora or IV) Just need to keep an eye on baby as they have had opiate exposure

Question 36

Which analgesics cannot be given in pregnancy

Answer 36

Cannot give NSAIDS In early pregnancy they have been associated with renal atresia In third trimester they can cause premature DA closure

Question 37

What caution must be taken when using biologics in pregnancy

Answer 37

Try and avoid in 3rd trimester as increased placental transfer so will affect foetus

Question 38

Which antibiotics would be used to treat PID in pregnancy

Answer 38

Ceftriaxone, metronidazole and doxycycline

Question 39

Which contraception can be put in place immediately after a C-section

Answer 39

Can insert a hormonal coil before closing

Question 40

When does breastfeeding act as a contraceptive

Answer 40

Only if exclusively breastfeeding, not having periods and baby is under 6 months

Question 41

What are the contraindications to placing a coil post C-section

Answer 41

- Only time you wouldn’t put in the coil is if she is septic or has massive fibroids

Question 42

How soon after birth can mum start taking the combined pill

Answer 42

Can’t use combined pill when breastfeeding until at least 6 weeks post-natal If not breastfeeding she would still need to wait 21 days due to clot risk

Question 43

What factors can affect drug levels in pregnancy

Answer 43

Increased blood volume (50% by 34 weeks) Increased clearance (glomerular filtration rate (GFR) 50% by 24 weeks) Increased hepatic metabolism Vomiting Decreased absorption Non compliance Fear of prescribing by medical professionals Therefore dose adjustment is needed in some cases

Question 44

Which type of steroids are metabolised by the placenta

Answer 44

Non-fluoronated such as prednisolone or hydrocortisone These are metabolised by the placenta so the foetus will get a lower dose In contrast flurinated are not metabolised so foetal dose is equivalent to maternal dose

Question 45

How can steroid use in pregnancy affect the foetus

Answer 45

Long term, high dose steroids may increase the risk of preterm rupture of membranes