Pharmacy Issues in Pregnancy- 20 Flashcards
When can conception occur.
Conception date might be the day sex occured or some days later as sperm can live in body for up to 5 days.
When can prenatal death occur.
weeks 1 and 2
when can major morphological abnormalities occur
Weeks 3-7
when can physiological defects and minor morphological abnormalities occur
Weeks 8-38
What are the 3 stages of foetal development and when do they occur.
Blastocyst formation- 0-16 days
Organogenesis 17-60 days
Histogenesis 61 days- full term
What physiological changes occur during pregnancy.
CV- Increased heart rate and decreased BP
GI- Decreased gastric acid secretion and gastric emptying
Renal- Decreased bladder capacity and urinary control.
What are the routes of the routes of transfer during pregnancy
Placenta
Respiratory function (gas exchange)
Excretory function (maintains water and pH balance)
Resorptive function (like GI tract)
What does the quantity of drug reaching the foetus depend on
The physio-chemical characteristics of the molecule and maternal pharmacokinetic parameters.
What are the three groups of degree of placental transfer
High: drug crosses rapidly, at equilibrium foetal conc close to the maternal pharmacological concentration
Limited: foetal concentration is lower than maternal concentration
Excess: Foetal concentration is higher than maternal
What are maternal factors to consider when prescribing in pregnancy
Implications of not taking the drug
Maternal choice
Gestation
Co-Morbidities
What are foetal factors to consider when prescribing in pregnancy
Risk of congenital malformations (weeks 1-8)
Risk of organ toxicity
Withdrawls post partum
What are drug factors to consider during pregnancy
Altered ADME
Narrowing of theraputic index
Safer alternative
Ability to cross placenta
Topical v Systemic
Adverse affects
What are common ailments related to pregnancy
Nausea and Vomiting- morning sickness
Haemorrhoids
Acid Reflux
UTI’s/Thrush
Anaemia
Infections
What is morning sickness when and why does it happen and how is it treated.
Nausea & Vomiting in 70-80% of all pregnant women
4-8 weeks gestation- rarely after 16 weeks
Hormonal, neurological, physical factors
increased hCG hormone, decreased gastric emptying)
Treatment is by anti-emetics
What are the causes of constipation and Haemorrhoids in pregnancy and how are they treated.
Constipation- Decreased motility of smooth muscle caused by an increase in progesterone or use of iron supplements.
Treated using bulk-forming laxatives.
Haemorrhoids- Enlarging of uterus exerts pressure, causes venous dilation.
Treated using anaesthetic creams or ointments.
How is indigestion caused in pregnancy and what is the treatment.
Caused increased gastric pressure due to the foetus.
Treated using gaviscon alginates
Have small frequent meals, avoid triggers foods.
How is thrush caused during pregnancy and what are the treatments.
Caused by hormonal changes in vaginal environment.
Treated via topical agents eg clotrimazole canestan cream or fluconazole one tablets oral (2nd line).
How are UTI’s caused in pregnancy and what are the treatments.
UTIsare very common duringpregnancy.
(growing foetus can put pressure on the bladder andurinary tract. This traps bacteria or causes urine to leak).
Do not treat OTC – refer to GP
Why is anaemia caused during pregnancy and what is the treatment
Iron deficiency can cause anaemia during infancy, spontaneous abortion, premature delivery, low birth weight of infant.
Treated using Iron supplements- variety of doses, usually 200mg FeSO4 or other iron salts –depending on tolerability. Also consider diet- leafy veg, cereals.
What are common conditions experienced in pregnancy.
Hypertension and pre-eclampsia
Gestational diabetes
Venous thromboembolism (VTE)
Obstetric cholestasis
Not for management in Community Pharmacy- although will be seen in Primary Care / GP.
What is a teratogen.
a substance, organism or process that causes malformations in a foetus (congenital abnormalities)
What can teratogenic substances cause in the foetus
Physical effects (structural abnormalities, dysfunctional growth-e.g 1st 6 weeks Heart & CNS- congenital heart defects or neural tube defects)
Behavioural effects- i.e effects on brain which manifest as behaviour – avoid psychotropic drugs.
What are major teratogenic drugs in humans
Anticoagulants
Warfarin
Antidepressants
Lithium
Anticonvulsants
Valproic acid
Carbamazepine
Chemotherapy
6-mercaptopurine
Methotrexate
Cyclophosphamide
Hormones
Androgens
19-Norsteroids
Retinoids
Isotretinoin
Acitretin
Thalidomide
What are the 5 FDA categories of teratogenic drugs
A - drug is well-studied and poses no threat to a developing baby
B – drug less-studied, but probably still low-risk
C is a drug that has not been studied and therefore the risk is unknown
D-based on animal or human data, may pose a risk
X means the drug, based on animal or human data, causes birth defects or there is no benefit for its use during pregnancy. Not recommended in pregnancy.
What are counselling points for taking drugs while breastfeeding
Insufficient evidence – advisable to administer only essential drugs to a mother during breast feeding
Use drugs with short half life
Feed just before mother takes medication (trough level)
Lipid soluble drugs diffuse into breast milk : concentrate because of high fat content of milk.
Generally, the quantity/conc of drug is too small to be of concern
