Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3RD YEAR SYSTEMS: Repro > Pharmacology in pregnancy > Flashcards

Pharmacology in pregnancy Flashcards

1
Q

Approximately what % of women of child-bearing age take some sort of medication?

A

80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why may a woman be on medicines during pregnancy, childbirth and lactation?

A

Hypertension
Asthma
Migraine
Epilepsy
Diabetes
Mental health disorders e.g depression/anxiety
Long-term anticoagulant therapy use e.g warfarin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pregnancy may affect any of the 4 basic kinetic processes. What are these?

A

Absorption
Distribution
Excretion
Metabolism and elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why might a pregnant women be unable to take oral medication?

A

Morning sickness - nausea and vomiting

Decrease in gastric emptying and gut motility - This is unlikely to be a problem with regular dosing, but may affect single doses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How might the absorption of an IM drug be altered in pregnancy?

A

Blood flow may be increased, so absorption may also increase using this route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How might the absorption of inhaled medication be altered during pregnancy?

A

During pregnancy a woman has increased cardiac output and increased tidal volume.

This may cause increased absorption of inhaled drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Drug distribution changes during pregnancy

A

Increase in plasma volume and fat will change distribution of drugs. So the volume of distribution will increase meaning more drug will be distributed to tissues (Esp fatty tissue)

Greater dilution of plasma decreases the relative amount of plasma proteins => results in increased fraction of free drug (unbound drug = active drug)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The hormones oestrogen and progestogen can inhibit which enzymes and ultimately alter drug metabolism?

A

They can induce or inhibit liver P450 enzymes which can increase or reduce metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give examples of medications affected by Oestrogen and progestogen?

A

Phenytoin - epilepsy medication - levels reduced during pregnancy due to induction of metabolism

Theophylline - COPD - levels increased due to inhibition of metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

By what % does the GFR increase in pregnancy?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What changes to medication may be required due to the increased GFR in pregnant women?

A

May need to increase the dose of the drug in order to obtain the required/correct plasma concentration of the drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What passes through the placenta from foetus to mother? (2)

A

CO2

Urea and other waste products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What passes through the placenta from mother to foetus?

A 
O2
Glucose
Amino acids
Lipids, FA's and glycerol
Vitamins
Ions
Alcohol, nicotine, drugs 
Viruses
Antibodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Look

A

Safest to assume all drugs will cross placenta

The placenta may also metabolise some drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How the drug affects the foetus depends on…

A

Rate at which drug crosses placenta and amount reaching the fetus

Duration of drug exposure

Distribution in different foetal tissues

Stage of placental and fetal development

Effects of drugs when used in combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does placental transfer depend on?

A

Molecular weight (smaller sizes will cross more easily)

Polarity (non-ionised molecules cross more readily)

Lipid solubility (lipid soluble drugs will cross)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is drug distribution different in the foetus?

A

Circulation is different (e.g. Umbilical vein to liver)

Less protein binding than adults therefore more “free” drug available

Little fat, so distribution different

Relatively more blood flow to brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is drug metabolism different in the foetus?

A

Reduced enzyme activity, although this increases with gestation.

Foetus exhibits different P450 isoenzymes to adults.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is drug excretion different in the foetus?

A

Excretion is into amniotic fluid – which the foetus swallows leading to recirculation.

Drugs and metabolites can accumulate in amniotic fluid.

Placenta not functioning at delivery so can be issues with excretory function,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Principles of prescribing in pregnancy

A

If you can, try non-pharmacological treatment first. If you have to use a medication… SAFEST DRUG, LOWEST DOSE POSSIBLE, SHORTEST TIME POSSIBLE (INTERMITTENT IF POSSIBLE)

Avoid the first 10 weeks of pregnancy if possible.

Consider stopping or reducing dose before delivery.

Never under treat disease which may be harmful to the mother or fetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Principles of prescribing for women of child-bearing age

A

Always consider possibility of pregnancy (planned or not!)

Warn women of possible risks

When treating medical conditions, advise women to attend before getting pregnant if planning to (optimise treatment)

Discuss contraception

If necessary, do not prescribe without contraception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 major risks of medication use in pregnancy?

A

Teratogenicity (first trimester)

Fetotoxicity (second and third trimester)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Look

A

Maternal chronic illness must be treated as under-treatment of maternal illness due to fear of using medicines during pregnancy may cause greater foetal risk!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When is the highest risk of teratogenicity?

A

3-8 weeks (organogenesis)

25
Q

Mechanisms of drug teratogenicity

A

Folate Antagonism

Neural Crest Cell Disruption

Endocrine Disruption: Sex Hormones

Induce foetal oxidative stress - imbalance of free radicals and antioxidants in the body

Vascular Disruption

Specific Receptor- or
Enzyme-mediated teratogenesis

26
Q

What process is key in DNA formation and new cell production?

A

Folate metabolism

27
Q

2 groups of drugs can affect folate metabolism. How do they work?

A

Block the conversion of folate to THF by binding irreversibly to the enzyme (eg methotrexate, trimethoprim)

Block other enzymes in the folate pathway (e.g. phenytoin, carbamazepine, valproate)

28
Q

What is normally the result of using folate anatogonistic drugs during pregnancy?

A

Tend to result in neural tube, oro-facial or limb defects

29
Q

Which types of drugs are Neural crest cell disruptions associated with?

A

Retinoid drugs e.g isotretinoin/’accutane’ (acne medication)

accutane is so potent that it can only be given if the woman is on contraception

30
Q

What problems can Retinoid drugs cause as a result of neural crest cell disruptions

A

Aortic arch anomalies

Ventricular septal defects

Craniofacial malformations

Oesophageal atresia

Pharyngeal gland abnormalities

31
Q

Enzyme-mediated teratogenesis

A

Drugs which inhibit or stimulate enzymes to produce therapeutic effects may also interact with specific receptors and enzymes damaging fetal development.

e.g NSAIDs - causing orofacial clefts and cardiac septal defects

32
Q

What are possible issues related to fetotoxicity?

A 
Growth retardation
Structural malformations
Foetal death
Functional impairment
Carcinogenesis
33
Q

Common drug example that causes fetotoxicity later in pregnancy and should NOT be given to pregnant women?

A

ACE inhibitors/ARBs

May cause foetal renal dysfunction and growth retardation

34
Q

Teratogenic drugs to avoid during pregnancy

A

Sodium valproate, phenytoin - neural tube defects

Warfarin - associated with haemorrhage in the fetus, as well as multiple malformations in the CNS and skeletal system.

ACE inhibitors - renal damage

NSAIDs - teratogenic and fetotoxic

Alcohol - foetal alcohol sydnrome

Retinoids - potent teratogenic

35
Q

Drugs and lactation

A

Almost all drugs/medication the mother takes will be present in breast milk

Important to know what concentration will be in breast milk - what are the potentially toxic effects of those when they move into the baby

36
Q

When considering drug therapy for a mother who is breast feeding what are the most important factors?

A

Minimal infant exposure

Treating the mother if completely necessary

37
Q

How is minimal exposure achieved?

A

If a drug needs to be used, then the mother should take the medication immediately after feeding the baby

Avoid breast-feeding during peak drug effect

Avoid drugs with long half-life or active metabolites

Drugs that are highly protein-bound are preferred

Extra caution if baby is severely ill or preterm.

38
Q

What 2 popular herbal galactagogues for nursing mothers pose a health risk to their infants?

A

Fenugreek

Comfrey

39
Q

What are considered preventable teratogens?

A

Alcohol
Smoking
Drugs i.e marijuana, ecstacy and cocaine

40
Q

What problems can smoking during pregnancy cause in the foetus/baby?

A

Low birth weight
Pre-term birth
Cerebral palsy
Learning difficulties

41
Q

What is Pharmacokinetics?

A

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.

Affected by pregnancy

42
Q

What is the 1st line treatment for nausea and vomiting during pregnancy?

A

Cyclizine- antihistamine

Prochloroperazine- phenothiazine

Doxylamine/pyridoxine combination product

43
Q

2nd line treatment for nausea and vomiting

A

Ondansetron

Metoclopramide

44
Q

What medication is given for hypertension in pregnancy?

A

Labetolol, nifedipine, methyldopa or hydralazine

45
Q

What common hypertensive medication is teratogenic and should NOT be given to pregnant women?

A

ACE inhibitors

46
Q

What are the safest drugs to give a pregnant woman to treat Epilepsy?

A

Carbamazepine and lamotrigine

47
Q

What should always be given with anti-epileptics in pregnancy?

A

Folic acid

48
Q

Diabetic treatment in pregnancy

A

Insulin = safest

Gestational diabetes / type 2 = metformin

All oral antidiabetic drugs, exceptmetformin, should be discontinued before pregnancy and substituted with insulin therapy.

Treatment is key if benefits from improved blood-glucose control outweigh the potential for harm

49
Q

Which drug is given to prevent thromboembolism in pregnancy?

A

Low molecular weight heparin = safe

50
Q

What is considered safe Asthma treatment during pregnancy?

A

Risks of medication use are lower than risk of untreated asthma

B2 agonist- albuterol, salbutamol - safe

Inhaled corticosteroid- budesonide

Systemic corticosteroid if severe asthma

51
Q

What medication is safe to use to treat headaches and migraines during pregnancy?

A

Paracetamol

Ibuprofen- persistent pulm hypertension- avoid in 3rd trimester!!

Sumatriptan- acute treatment of migraine

Propanolol lowest effective dose

52
Q

True or false: Morphine is used as labour analgesia

A

True

53
Q

Antidepressants and antipsychotics during pregnancy

A

Need to weigh risk vs benefits of treatment

Selective Serotonin Reuptake Inhibitor (SSRI) - Where the benefits of SSRI use outweigh potential risks, use of SSRIs during pregnancy may be indicated.

54
Q

What antibiotics are considered safe during pregnancy?

A

Penicillin- generally safe- check allergy

Macrolide- azithromycin/erythromycin- use only if no alternative

Sulphonamides- teratogenic-avoid in first trimester- folate antagonist

Cephalosporins- generally safe

55
Q

Is Tetracycline safe during pregnancy? (Antibiotic)

A

No

Animal studies show it has effects on skeletal development and can cause discolouration of teeth

56
Q

Are Aminoglycosides safe during pregnancy?

A

No

Can result in auditory or vestibular nerve damage -The risk is greatest with streptomycin.

57
Q

Look

A

Most cytotoxic cancer drugs are teratogenic

Exclude pregnancy before starting these medications

58
Q

If a woman in labour has had no analgesia but is crying out for pain relief what should be given first (before morphine)?

A

Inhalation Analgesia (Entonox)

3RD YEAR SYSTEMS: Repro (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions