Drugs in pregnancy

Question 1

teratogen

Answer 1

Greek translation - monster

Causes abnormality within the baby following fetal exposure during pregnancy

Usually discovered- after increased prevalence of a particular birth defect

first half of pregnancy is the most vulnerable- affect embryogenesis

Question 2

what are preventable teratogens

Answer 2

cohol- fetal alcohol syndrome

Smoking- low birth weight, preterm birth, cerebral palsy, learning difficulties

Marijuana, ecstacy, cocaine- low birth weight, withdrawl symptoms, learning and behavioural problems

Question 3

what is pharmokinetics

Answer 3

What the body does to a drug

Movement of the drug through, and out of the body

the time course - absorption, bioavailability, distribution, metabolism, and excretion.

Question 4

what are pharmacodynamics

Answer 4

What the drug does to the body
Biochemical /physiologic/ molecular effects of drugs on body
Receptor binding/post receptor effect

Normal physiologic changes in pregnancy lead to alteration in the pharmacokinetics of the drug and may affect the pharmacodynamics

Question 5

how should Nausea and vomiting be treated in a pregnant woman

Answer 5

Cyclizine- antihistamine
Prochloroperazine- phenothiazine
doxylamine/pyridoxine combination product (Xonvea®) was licensed for the treatment of NVP in the UK in 2018 and can also be offered as a first-line option.

Second line- ondansetron, metoclopramide

Question 6

how do you treat hypertension in a pregnant lady

Answer 6

Labetolol, nifedipine, methyldopa, hydralazine

Teratogenic medicines – ACE inhibitors, angiotensin receptor antagonist – change as soon as pregnancy confirmed

Question 7

how do you treat epilepsy in a pregnant woman

Answer 7

Pregnancy- Change in free serum conc of antiepileptics
Carbamazepine and lamotrigine- safest

Phenobarbitone- cardiac malformations
Sodium valproate- NTD, facial clefts

Always give high dose folic acid

Question 8

how do you treat epilepsy in a pregnant woman

Answer 8

Insulin – safest
Gestational diabetes/ type 2- metformin

NICE- All oral antidiabetic drugs, except metformin hydrochloride, should be discontinued before pregnancy (or as soon as an unplanned pregnancy is identified) and substituted with insulin therapy. Women with diabetes may be treated with metformin hydrochloride [unlicensed in type 1 diabetes] as an adjunct or alternative to insulin in the preconception period and during pregnancy, when the likely benefits from improved blood-glucose control outweigh the potential for harm. Metformin hydrochloride can be continued, or glibenclamide resumed, immediately after birth and during breast-feeding for those with pre-existing Type 2 diabetes. All other antidiabetic drugs should be avoided while breast-feeding.

Question 9

how do you treat thromboembolism in a pregnant lady

Answer 9

Low molecular weight heparin (LMWH)- safe
Warfarin- fetal warfarin syndrome/fetal embryopathy
nasal hypoplasia and skeletal abnormalities, including short limbs and digits, and stippled epiphyses, is a well-recognised complication of first trimester warfarin use in pregnancy
Avoid in 1st and third trimester

directly-acting anticoagulants (DOACs, e.g. apixaban, dabigatran, edoxaban and rivaroxaban)- manufacturer advises to avoid-animal toxicity

Question 10

how do you treat asthma in a pregnant women

Answer 10

Risk of medication use are lower than risk of untreated asthama
B2 agonist- albuterol, salbutamol - safe
Inhaled corticosteroid- budesonide
Theophyline- potential toxicity
Systemic corticosteroid- severe asthama

Question 11

how do you treat a migraine in a pregnant woman

Answer 11

Paracetamol
Ibuprofen- persistent pulm hypertension- avoid in 3rd trimes

Sumatriptan- acute treatment of migraine

Propanolol lowest effective dose

Question 12

morphine based medicines safety

Answer 12

No increase in congenital abnormalities
Risk of neonatal respiratory depression and with drawl
Used as labour analgesia
Avoid codeine during lactation- infant opiate toxicity

Question 13

antidepressants and antipsychotics

Answer 13

SSRI- Where the benefits of SSRI use outweigh potential risks, use of SSRIs during pregnancy may be indicated. The risks of destabilisation and maternal relapse must be taken into account when considering discontinuing SSRIs
Lithium- ebstein’s anomaly- cardiac anomaly
Diazepam- old studies clefts lip/palate- floppy infant syndrome
Quetiapine- large baby, poor neonatal adaptation syndrome

Weigh risk vs benefits of treatment

Question 14

antibiotics

Answer 14

Penicillin- generally safe- check allergy

Macrolide- azithromycin/erythromycin- use only if no alternative

Tetracycline- do not prescribe, animal studies- effects on skeletal development, discolouration of teeth

Sulphonamides- teratogenic-avoid in first trimester- folate antagonist

Aminoglycosides- auditory or vestibular nerve damage -The risk is greatest with streptomycin.

Cephalosporins- generally safe

Question 15

Cancer treatments

Answer 15

Most cytotoxic drugs are teratogenic

Exclude pregnancy before starting these medications

Take specialist advice- if needed to start or continue treatmet in pregnancy

Question 16

Corona virus treatments

Answer 16

Hydroxychloquine- no significant increased risk of major malformations in general, as well as craniofacial, cardiovascular, nervous system and genitourinary malformations specifically, and no significant increase in stillbirth, low birth weight or prematurity risks.
Azithromycin- macrolide antibiotics- Although individual studies have described increased risks of miscarriage and overall malformation following azithromycin use in pregnancy, the majority of studies do not support these findings.
Tocilizumab- Although adverse pregnancy outcomes have been described (including cases of congenital anomaly, miscarriages and preterm deliveries), the crude rates of these events do not generally appear to be notably increased above the background rate.
Lopinavir/ritonavir- protease inhibitors- approximately 3,000 exposed pregnancies and do not suggest an increased risk of malformation.[10] Studies investigating neurodevelopmental outcomes have also provided reassuring findings.[10] However, cases of preterm delivery, low birth weight and stillbirth have also been described.[24] Due to data limitations, the risk of these outcomes following maternal lopinavir/ritonavir use in pregnancy is currently undetermined.
Corticosteroids- majority of the best quality evidence does not suggest increased risks in either the overall malformation rate, or for specific malformations (including orofacial clefts and cardiac anomalies). The small number of methodologically limited studies investigating miscarriage and intrauterine death risks do not provide reliable evidence of increased risks, and similarly there is no reliable evidence indicating use of systemic corticosteroids impairs fetal growth