Drugs And The Endocrine System Flashcards
Name the endocrine systems?
Pituitary glands, thyroid glands, adrenal glands, ovaries, kidneys
Explain thyroid disease
Affects the CNS, CVS, metabolic rate Symptoms: Hyperthyroidism -anxious, nervous, tremor, insomnia -hypertension, tachycardia, palpitations -low grade fever, intolerance to heat, increased appetite, weight loss
Hypothyroidism
- slow speech, lethargy, hyporeflexia
- hypotension, bradycardia, anaemia
- weight gain, low body temperature, intolerance to cold
Define goitre
Swelling of the neck due to increased thyroid gland
What happens in under active goitre?
1- not enough iodine, so insufficient T3/T4
2- disruption to the negative feedback
What happens in an overactive thyroid?
1- activation of the TSH receptors by antibodies (Graves’ disease)
2. Increase in size and function of thyroid gland
What happens in hyperthyroidism?
Graves’ disease autoimmune condition
Thyroid cells stimulated by auto-antibodies
Patients undergo remission
Treatment doesn’t cure but suppresses hyperthyroidism
What is the treatment for hyperthyroidism?
Carbimazole or propylthiouracil
Limit iodine intake
Long term treatment: surgery or radioactive
Iodined replacement therapy “block and replace”
UK: propylthiouracil reserved for patients who are intolerable to carbomazole
How does carbimazole work?
It inhibits the synthesis of thyroxine
Used for 4-6 weeks
Initially take 15-40mg daily until euthyroid the reduced dose
It’s absorbed through the gut , converted in the liver to its active form
Excreted via urine
Short 1/2 life
Active form is methimazole, accumulates in the thyroid gland agranulocytosis- bone marrow suppression presents as sore throat
What are the side effects of carbimazole?
Nausea Allergic rash/ itching Agranulocytosis Insomnia Can transfer across placenta and in breast milk resulting in neonatal hypothyroidism
Explain hypothyroidism
Patients require thyroxine substitute (T4) If severe administer T3 via IV
T3 much lower half life-balance blood level
What drugs are used for hypothyroidism?
Oral thyroxine/ levothyroxine t4
IV Triiodothyronine T3
Why is calcium needed in the body?
Calcium is the main hormone for remodelling bones
The parathyroid hormone promotes calcium absorption from the kidneys
Calcitonin (C cells) inhibits osteoclasts and reabsorption from the kidneys and so reduce calcium levels
Calcitriol (vitamin d3) increases calcium levels by increasing bone mobilisation and increase reabsorption from the gut
What are the causes do hypocalcaemia?
Inadequate calcium intake
Deficiency in PTH or lack of vitamin d3
Renal problems
What are the symptoms of hypocalcaemia?
Neuromuscular problems Muscle cramps Paraesthesia in extremities Over time- mental deficiency Fits Cataracts
What are the treatments for hypocalcaemia?
Calcium glucoronate IV infusion
Ergocalciferol (vitamin d)- can only be sued if kidney function is not compromised- or calcitriol
Why does hypercalcaemia need urgent attention?
Caused problems with the kidneys(stones), renal failure
Muscle problems- cardiac arrest
(Problems only last 2 days MAX)
What are the treatments for hypercalcaemia?
Bishops phoneys and calcitonin
Explain the use of biphosphonates.
Used to treat osteoporosis
Oral administration
AA slows rate of bone growth and turnover so prevents calcium loss from bones
Patient must not eat within1/2 hour of taking the medication, as food prevents proper absorption
What are the side effects of biphosphonates?
Abdominal pain
GI disturbance
Oesophageal problems
Explain use of calcitonin.
Usually from salmon-salmontonin Expensive Short life Ineffective with continuous use Nasal spray or SC or IM
Explain steroids in the body
Hormones
Can be given synthetically to treat for endocrine dysfunction or immune disorders
Most synthetic drugs have minercorticoid and glucocorticoid activity
What does glucocorticoids do in the body?
Cortisol or hydrocortisone increase glucose mobilisation (gluconeogenesis)
What does minieralocorticoid do in the body?
Aldosterone increase sodium retention and thus h20 retention, and potassium loss in DCT of the kidney nephron
Where is steroids secreted from?
Cortex of adrenal glands
Which drug is used to treat adrenal insufficiency?
Fludrocortisone
Use of glucocorticoids?
Administered orally
Metabolised in liver
Used topically for eczema (h45 cream)
Given low does orally for Addison’s disease/ crisis-adrenal insufficiency
Higher dose for the reduction of information following acute allergy
What are the four types of glucocorticoids?
Prednisolone- orally, acute asthma attack
Methylprednisolone- oral or parenterlly, not via GI tract, prevent rejection of transplant
Dexanethasone- orally or parenterally, high anti inflammatory action, treat cerebral oedema
Beclametasone- inhalation(brown inhaler), treat asthma
What are the effects of oral glucocorticoids?
Hydrocortisone- low dose few adverse effects. High dose both glucocorticoid and minieralocorticoid effects
Dexamethasone: glucocorticoid systematic effect
Topical therapy minimised effects
Cushingoid features Oral thrush Hoarseness Psychiatric reactions Risk of chicken pox
What is the withdrawal plan?
Gradual, If sudden can disrupt the negative feedback mechanism of ACTH/cortisol Low BP Low Glucose High potassium Low sodium Steroid card
What are the types of reproductive steroids?
Oral contraceptives
Hormone replacement therapy
Oestrogens
Progesterone
Why use oral contraception?
Contains one or more female sex hormones, prevents conception. Blocks the normal process of ovulation and menstrual cycle
What is the combined pill?
Inhibits ovulation
Taken for 21 days, stopped for 7
Uterine bleeding during withdrawal period
Absorbed lol orally
Metabolised by liver
Excreted in bile
Can be prescribed for dysmenorrhea (regulate menstrual cycle)
Reliable and reversible
Reduces PMT
High dose can be given as morning after pill up to 72 hours
Adverse effects of the combined pill
MI and Strokes risk increase in smokers Hypertension Venous thromboembolytic disease - DVT/PE- high oestrogen preparation more risk p, increase clotting capacity of blood. Common with gestodene( new progesterone preparations) Links to carcinomas cervical/ breast Headaches
What is the mini pill?
Progesterone only pill
Alters the endometrium and cervical mucus to prevent implantation
Inhibits ovulation in 40% of women
Medroxyprogesterone- injection lasts 3 months or orally
What are the effects of the mini pill?
Nausea
Vomiting
Breast discomfort
What are the drug are the drug reaction?
Both combined pill and mini pill interact with hepatic enzyme inducers causing an increase in metabolism
Some antibiotics also have similar effect (amoxycillin, ampicillin, doxycycline) reduce the effectiveness
When is HRT used?
Post menopausal women
Decrease in oestrogen levels and increase in LH/FSH
Cessation of ovulation
What risks are involved in HRT?
CVD
Oestrogen levels in pills
Osteoporosis
What does HRT treat?
Symptoms
Daily dose orally: oestrogens, oestrodiols
Flushes, long term use- breast cancer
What are the hormone modulators?
Tamoxifen-treat breast cancer, prophylaxis in high risk patients
Oestrogen receptor antagonist reduce oestrogen levels
Clomiphene- fertility treatment, oestrogen antagonist, inhibits the negative feedback if FSH/LH, can result in multiple births
Somatatrophin-analogue of hGH, short stature children, turners syndrome or after pituitary surgery. IM OR SC. insulin resistance. Swelling, join pain, headaches
Oxytocin-PP- induce labour. Reduce post-Parton haemorrhage
How is the endocrine system managed?
Hormones
