drugs and the endocrine system Flashcards
what are endocrine diseases?
hormones involved - wide spread and diverse effects on body
hormone deficiency
hormone over activity
what is thyroid disease and what does it affect?
can be hypothyroidism or hyperthyroidism
can affect CNS, metabolism and CV system
what are the symptoms of hypothyroidism?
slow speech lethargy hypotension bradycardia anaemia weight gain low body temp intolerant to cold (everything depressed - under active)
what are the symptoms of hyperthyroidism?
anxiety nervousness hypertension tachycardia low grade fever inholerant to heat weight loss (everything activated - over active)
is a goitre present in hypo or hyperthyroidism?
both
what causes a goitre in hypothyroidism?
not enough iodine so insufficient T3 and T4
disrupts negative feedback
no TSH production
what causes a goitre in hyperthyroidism?
activation of TSH receptors by antibodies
increase in size and function of thyroid gland
what causes hyperthyroidism?
thyroid cells stimulated by auto-antibodies (autoimmune disease such as graves disease)
can treatment cure hyperthyroidism?
no but can supress
give two examples of drugs used to treat hyperthyroidism
Carbimazole
Propylthiouracil
(plus limited iodine intake)
what treatments other an drugs can be used to treat hyperthyroidism?
surgery or radioactive iodine - block and replace therapy
what does the drug carbimazole do to treat hyperthyroidism?
blocks T3 and T4 production - this is then replaced in small amounts
interferes with synthesis of thyroxine
(short half life)
where is carbimazole absorbed, activated and excreted?
absorbed in gut
activated in liver
excreted in urine
what are the side effects of carbimazole?
nausea
rash
agranulocytosis - deficiency of granulocytes in blood causing increased risk of infection
can cross placenta causing neonatal hyperthyroidism
how is hypothyroidism treated?
with thyroxine substitute
name two thyroxine substitutes
levothyroxine T4
triiodothyronine T3 - severe cases (IV)
which thyroxine substitute has a shorter half life and balances blood level?
triiodothyronine T3
name two drugs which can cause hypothyroidism
lithium (depression)
amiodarone (antiarrhythmic)
which hormone promotes reabsorption of Ca2+ from the kidneys?
parathyroid hormone
what does calcitonin (c-cells) do?
reduces Ca2+ - inhibits osteoclasts and reabsorption of Ca2+ from kidneys
what does calcitriol (vit D3) do?
increases Ca2+ - increase bone mobilisation and increase reabsorption in gut
what is hypocalcaemia?
not enough calcium
what are the symptoms of hypocalcaemia?
neuromuscular probs muscle cramps mental probs seizures cataracts
what are the causes of hypocalcaemia?
reduced Ca2+ intake (diet)
deficiency in PTH
lack of vit D (needed for absorption of Ca2+)
renal probs
what is used to treat hypocalcaemia due to vit D deficiency?
ergocalciferol (vit D) - good kidney function needed
calcitriol
what is used to treat hypocalcaemia due to Ca2+ deficiency?
calcium glucornate IV infusion - with or within calcium
what is hypercalcaemia?
too much calcium - urgent help needed
what symptoms would hypercalcaemia cause?
kidney stones
renal failure
muscle probs
cardiac arrest
what treatments would be used for hypercalcaemia?
Biphoshonates
Calcitonin - inhibits osteoblasts and reabsorption of Ca2+ from kidneys (reduces plasma Ca2+ levels)
which biphoshonate would be used to treat hypercalcaemia? and how does it do this?
alendronic acid - slows bone growth and turnover/ prevents Ca2+ loss (treats osteoporosis)
what side effects does alendronic acid have?
abdominal pain
GI problems
Oesophageal probs
why would alendronic acid be used instead of calcitonin?
(usually from salmon - salmaonin)
expensive
short half life
ineffective long term
name 4 steroids that are released naturally from the adrenal cortex but can also be given synthetically to treat endocrine dysfunction and immune disorders
corticosteroids
mineralocorticoids
glucocorticoids
endogenous hormones
what is the function of glucocorticoids?
lower BP
lower glucose
name five glucocorticoids?
hydrocortisone (cortisol) prednisolone methylprednisolone dexamethasone beclametasone
what is hydrocortisone (cortisol) used to treat and how is it administered?
treats Addison’s disease/ crisis and adrenal insuffiency
reduces inflammation in acute allergy
administered - oral/ IV/ topically
what is prednisolone used to treat?
treats acute asthma attacks (5x stronger than hydrocortisone)
what is methylprednisolone used to treat?
prevents rejection of organ transplanted (given parentally - not via GI tract)
what is dexamethasone used to treat and how is it administered?
high anti-inflammatory action (20x stronger than hydrocortisone )
treats cerebral oedema
administered orally or parentally
what is beclametasone used to treat?
asthma - brown inhaler
do glucocorticoids produce local or systemic effects?
wide systemic effects
list some of the adverse side effects of oral glucocorticoids
buffalo hump hypertension muscle wasting osteoporosis moon face increased abdo. fat thinning skin poor wound healing (known collectively as cushingoid features)
glucocorticoids cause stunting of growth, how does this differ between oral steroids and inhaled beclamethasone?
oral steroids - growth greatly stunted/ cushingoid features
inhaled beclamethasone - growth less affected/ no cushingoid features
what are the unwanted effects of inhaled glucocorticoids?
local immunosuppression in mouth/throat can cause opportunist candida albicans (oral thrush)
vocal cords affected - dysphonia (hoarseness) can result
what can reduce the unwanted effects of inhaled glucocorticoids?
using a spacer
rinsing mouth after inhaler used
what other side effects are associated with glucocorticoids
- psychiatric reaction (rare - high dose of systemic glucocorticoids) - prescribe with care to patients with existing or predisposition to mental health issues.
- risk of chickenpox
what would you advice patients when prescribing glucocorticoids?
immunosuppression
adrenal suppression
mood changes
GI tract probs
when stopping glucocorticoids use how must the process be managed and why?
glucocorticoids must be withdrawn slowly
abrupt withdrawal causes neg. feedback of ACTH/cortisol disruption - patient could enter addisonian crisis
what are the symptoms of an addisonian crisis?
low BP
low glucose
high K+
high Na
name two commonly used reproductive steriods
oral contraceptives-
combined pill
mini pill
describe how the combined pill is used and how it works
oestrogen and progesterone
inhibits ovulation
21days pill then 7days no pill
what are the benefits of the combined pill?
regulates menstrual cycle
reliable/reversible
reduces PMT
high dose - morning after pill
what are the risks associated with taking the combined pill?
MI /stroke hypertension DVT or PE cervical/breast cancer headaches
describe how the mini pill works
progesterone only inhibits ovulation (40%) alters endometrium/cervical mucus
what is medroxyprogesterone?
depot - progesterone only contraceptive injection
what are the risks associated with the mini pill?
nausea
vomiting
breast pain
how does the combined pill inhibit ovulation?
stimulates negative feedback which in turn inhibits the release of FSH, LH and GnRH
what happens to women post menopausally?
reduced oestrogen levels = ovulation stops
increased LH/FSH
how is the menopause treated?
using HRT - oestrogen (50ug)/oestrodiols
what are the risks associated with HRT?
cardiovascular disease osteoporosis cancer DVTs breast cancer
what are hormone modulators?
drugs that can be given to modulate the effect of hormones occurring naturally in the body
name five drugs which are given to modulate hormones
- tamoxifen - breast cancer due to oestrogen
- Clomiphene - stimulates ovulation
- somatatrophin
- oxytocin peptide hormones (PP)- induces labour (used with ergometrine to reduce haemorrhage
- prostaglandins - causes muscle contraction - induce labour/abortion
what is somatatrophin used for?
analogue of hGH
used in stunted growth (children)
turners syndrome/ russel silver syndrome (no appetite)
* also used after pituitary surgery
