therapeutics Flashcards
where does primary thyroid disease affect
thyroid gland
where does secondary thyroid disease affect
pituitary gland
where does tertiary thyroid disease affect
the hypothalamus
where is the thyroid located
below the larynx in the neck region
causes of primary hypothyroidism
autoimmune disease
previous treatment for hyperthyroidism
iodine imbalance
congenital hypothyroidism
risk factors of primary hypothyroidism
female
symptoms of hypothyroidism
lethargy/weakness dry scaly skin depression hair loss memory loss weight gain constipation sensitive to cold weather
what is primary hypothyroidism
high levels of TSH but low levels of unbound t4
what thyroid function tests are carried out
TSH and unbound t4
management of primary hypothyroidism
treat with lifelong t4 If TSH >10 or TSH 5-10 with low t4.
what is the daily maintenance dose of thyroxine
50-200mcg
what initial dose of thyroxine should a person with heart disease and over 50 have
25mcg od adjusted by 25mcg
what initial dose of thyroxine can a person under 50 have
50-100mcg adjusted by 25-50mcg
how long after prescribing thyroxine should TSH be measured
after 8-12 weeks
what is he half life of t4
7 days
how often should TSH levels be monitored in adults and children when prescribed thyroxine
every year for adults and every 4-6 months for children until they hit puberty
during thyroxine treatment what should be carefully monitored
angina
what other combination treatments can be considered for hypothyroidism
liothyronine and levothyroxine or natural thyroid extraction`xt
are there any prescription charges for thyroxine
no
what should you not take at the same time as thyroxine
calcium iron containing preparations or any caffeine beverages
what is hyperthyroidism
low TSH high unbound t4
what causes hyperthyroidism
stimulation of thyroid gland by antibodies on the TSH receptor
risk factors
females
symptoms
anxious, palpitations, tremor, weight loss, tachycardia, goitre, warm moist skin, heat intolerance, difficulty sleeping
what is the most common drug therapy used for hyperthyroidism
carbimazole (methimazole is active metabolite)
moa for hyperthyroidism drugs
inhibit thyroperoxidase activity in follicular lumen
what drug is used to treat hyperthyroidism in pregnancy
propylthiouracil 200-400mg DIVIDED DOSES maintenance 50mg tds.
carbimazole regimen
15-40mg od until TFTs normal then maintain for 12-18months then decrease monthly until 5-15mg.
what is the blocking replacement regimen
carbimazole 40-60mg for 4 weeks the carb + thyroxine 50-100mg = temporarily hypothyroid. treat for 18 months
are prescription charge necessary for treatment of hyperthyroidism
yes
why can’t carbimazole be used in pregnancy
increased foetal nail abnormalities. advise on contraception
carbimazole side effects
agranulocytosis e.g. sore throat, mouth ulcer, bruising
propythioluracil side effects
hepatic dysfunction
in which case is radioactive iodine treatment considered
severe disease, failure to drug treatment, relapse after drugs, cardiac disease
risks of surgery
high chance of long term hypothyroidism, damage to parathyroid gland, scarring
what other combination treatments are considered for hyperthyroidism
beta blockers - relieve symptoms of palpitations/tremor (not in asthma)
propranolol - may ned to be given more frequently as increased metabolism
what happens with an overdose of iodine
inhibition of t3/4 release from thyroid
why does amiodarone cause problems in thyroid disease
it contains organic iodine which inhibits t3/4 in hypothyroidism and increases TSH and t4 in hyperthyroidism
problems associated with lithium
prevents t3+4 release as it inhibits iodine uptake
