What would happen if a healthy person took thyroxin pills?

Question

a. The level of TSH in the blood would increase
b. the output of TSH-RF (TSH-RH) would increase
c. The thyroid would increase it's activity
d. There would be an increase in metabolic activity of body cells, but negative feedback would shut down the thyroid
e. none of the above

Answer 1

I would say 'D'; like most hormone systems, thyroid hormones like thyroxin are regulated partly by negative feedback. This means that as the concentration of the specific hormone increases, it will have an inhibitory effect of the gland cells that produced it. This makes sense, because if you have a lot of hormone being made, you naturally want it to slow down eventually. Since thyroxin boosts metabolic activity, you'd see a spike in cellular metabolism, and an almost completely inhibited thyroid gland.

Answer 2

THYROXINE - a patient's guide
Editorial Team


BRAND NAME: Eltroxin

USE: Thyroid hormone (hypothyroidism)

This medicine is primarily indicated for the treatment of hypothyroidism (underactive thyroid gland), where thyroxine is used as replacement therapy in people having a lower thyroid function than normal. Treatment is usually long term as it is replacing thyroid hormone the body is not producing. The dosage is usually adjusted according to response and blood test results.

Caution:

Patients with heart disease (angina) should start the medication cautiously on a low dose and build up as needed under medical supervision.

Other cautions to be aware of include:

Adrenal insufficiency

Breastfeeding

Thyrotoxic crisis ('thyroid storm')

Elderly - slowly on a low dose and build up if needed.

Diabetics (raises sugar levels)

Side effects:

Dose related:

chest pain (also an increase in heartbeat)

muscle cramps

stomach upset

weight loss

restlessness and insomnia

headache

sweating and hot flushes

Side effects usually reside after a dose reduction is made by your doctor.

Overdose:

Results in excess irritability, confusion, sweating and other side effects (seek urgent medical help).

Interactions:

Thyroxine increases the effect of warfarin, tricyclic antidepressants and amiodarone.

Oral contraceptives, anticonvulsants, cholestyramine and rifampicin may reduce efficacy.

Patient information:

Follow the instructions on the label of this medicine.

Used as maintenance therapy therefore should be taken regularly (do not stop taking this medicine unless directed by your doctor). If you miss a dose, it is not necessary to take an extra dose, as the drug is very long-acting.

Contact your doctor or seek medical help if side effects are severe or ongoing.

Answer 3

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