Preg & Breast - L1 Prescribing

Question 1

Fetus contraindications - 6

Answer 1

Consider certain medical conditions exacerbated by some drugs e.g. avoid B blockers with asthma, pethidine with epilepsy, ergometrine BP
Contraindications (for fetus):
1. Methotrexate
2. Radioactive iodine
3. Lithium
4. Isotretinoin
5. Sodium Valproate
6. Warfarin

Question 2

Pre-pregnancy - 6

Answer 2

1. Are their safer alternatives?
2. Should they delay pregnancy to optimize medical condition?
3. Pre-pregnancy counselling
4. Only switch drugs in pregnancy if meds unsafe and suitable alternative
5. Different drugs at varying gestations
6. Lifestyle e.g. Nicotine, alcohol, drug addiction

Question 2

Time frames of Pregnancies - 3

Answer 2

1. Within 20 days after fertilisation: foetus is highly resistant to birth defects; so, drugs have an all-or-nothing effect (death or no effect)
2. 3-8 weeks after fertilization: Possibly no effect, miscarriage, birth defect; organ development, particularly vulnerable to birth defects
3. 2nd & 3rd trimesters: Changes in growth & function of normally formed organs & tissue, unlikely to cause obvious birth defect but unknown long-term effects; Organ development complete

Question 3

Early pregnancy – 5

Answer 3

1. Plasma levels change, reduced absorption, dilution, excretion
2. Increase [drug]
3. Teratogenesis
4. S/Es of Hormones of Pregnancy
5. Hyperemesis: Cyclizine, Metoclopromide, Prochlorperazine, Ondansetron & Steroids

Question 4

Teratogenesis – 3

Answer 4

1. <1 in 20 of babies with congenital abnormality attributed to drugs – difficult to estimate because most of the abnormalities can also occur spontaneously
2. If a teratogenic agent is taken during the period of embryogenesis (up to 8 weeks) the result will be an anatomical malformation
3. Later in pregnancy function will be affected

Question 5

Epilepsy - 7

Answer 5

1. Carbamazepine, valproate, phenytoin & phenobarbitone are all teratogenic
2. NTDs esp. valproate & carbamazepine
3. Congenital cardiac defects esp. valproate & phenytoin
4. Orofacial clefts linked with phenytoin usage
5. Risk increases with poly-pharmacy – 6-7% for one drug, 15% for two and up to 50% for three
6. With valproate the effect is dose-dependent. If taking >1g/day risk 6x that if on 600mg/day
7. Lamotrigene similarly dose-dependent – try to control with <200mg bd

Question 6

Epilepsy minor malformations - 5

Answer 6

1. low-set ears
2. broad nasal bridge
3. irregular teeth
4. hypoplastic nails & digits
5. untreated maternal epilepsy associated w/ increased risk of cognitive abnormality

Question 7

Asthma in pregnancy – 10

Answer 7

1. Foetal growth restriction
2. Preterm birth
3. Increased perinatal mortality
4. Neonatal hypoxia (insufficient oxygen for homeostasis)
5. Hyperemesis (nausea & weight loss)
6. Hypertension
7. Pre-eclampsia (high BP & protein in urine)
8. Vaginal haemorrhage Complicated labour
9. Steroid treatment may increase the risk of cleft

Question 8

Asthma advice in pregnancy - 4

Answer 8

1. Pregnant patients: give drug therapy for acute asthma. Give High flow O2 to prevent maternal & foetal hypoxia
2. Use inhalers as normal (short & long-acting beta 2 agonists; corticosteroids; oral theophylline)
3. Offer oral corticosteroids to treat exacerbations of asthma (benefits outweigh risks)
4. If Leukotriene receptor antagonists or long-acting muscarinic receptor antagonists are needed to achieve asthma control, then should not be stopped

Question 9

Diabetes in pregnancy - 6

Answer 9

1. Insulin remains No.1 drug for Type 1, 2 & uncontrolled Gestational Diabetes
2. Human placenta produces Lactogen, cortisol & glucagon
3. All ANTI-INSULIN: raise in baseline blood glucose levels
4. Preconception counselling is essential
5. Regular antenatal monitoring & dose adjustments
6. Early Intervention for delivery if dramatic dose reducing requirements

Question 10

T1 & 2D - 5

Answer 10

1. Risk of hyperglycemia preconception & during organogenesis:
2. Structural abnormalities of CVS, CNS or GUS
3. Pregnancy loss: spontaneous miscarriage or still birth
4. Euglycemia does NOT eradicate these risks
5. MDT input essential: diet, lifestyle, HBA1c levels, adjust insulin levels

Question 11

2nd & 3rd trimester risks of diabetes - 6

Answer 11

1. Macrosomia 4.5kg (overweight baby)
2. Shoulder Dystocia (tearing)
3. Neonatal Admission
4. Neonatal Hypoglycemia
   Infancy & beyond:
5. Childhood obesity
6. Adult Diabetes

Question 12

Hypertension – 6

Answer 12

1. Pre-exist pregnancy or develop as a result
2. Risk of Pre-eclampsia: pregnancy specific condition
3. CVD is the no 1 cause of maternal deaths
4. Pregnancy threshold for treatment is 140/90- aim for BP<135/85mmHg
5. Treatment: Methyl dopa, Nifedipine, Labetalol (orally & IV), Hydralazine
6. Contra-indicated: ACE inhibitors, diuretics & ATII receptor blockers

Question 13

Mental health – 4

Answer 13

1. SSRIs benefit outweigh the risks
2. Possible placental transfer & risks newborn withdrawal
3. Monitor 48 hours after birth
4. Breast feeding benefit outweighs the risk

Question 14

Analgesia - 3

Answer 14

1. Paracetamol: Safest drug out there
2. NSAIDS: best avoid especially in 3rd trimester
3. OPIATES: risk of neonatal withdrawal if taken for prolonged periods, especially in month leading up to birth