Clinical pharmacology

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Clinical pharmacology

• Thyroid disorders

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Thyroid Function Tests

• "TSH" Test -- Thyroid Stimulating Hormone / Serum
  thyrotropin

Under .4 can indicate possible hyperthyroidism. Over 6 is considered indicative of hypothyroidism.)
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Thyroid Function Tests

• Free T4 / Free Thyroxin - FT4
• Less than 0.7 is considered indicative of
  possible hypothyroidism.
• T3 / Serum triiodothyronine
• Less than 80 can indicate hypothyroidism.

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Thyroid disorders Imbalance in production of
thyroid hormones arises from dysfunction of the
thyroid gland itself, the pituitary gland, which
produces thyroid-stimulating hormone (TSH), or
the hypothalamus, which regulates the pituitary
gland via thyrotropin-releasing hormone (TRH).
Concentrations of TSH increase with age,
requiring age-corrected tests. Hypothyroidism
affects between three and ten percent of adults,
with incidence higher in women and the
elderly. Hypothyroidism may cause cretinism and
myxodema. Hyperthyroidism causes Graves disease.
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Thyroid disorder

• Hyperthyroidism is a condition in which the
  thyroid gland makes too much thyroid hormone,over
  long or short period.
• Causes.
• Getting too much iodine
• Graves disease
• Inflammation (thyroiditis).
• Noncancerous growths of the thyroid gland
  Symptoms,.
• Fatigue-Goiter-Heat intolerance-Increased
  appetite-Increased sweating-Weight loss -High
  blood pressure-exophthalmos-(palpitations)

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Diagnosis treatment

• Blood tests are also done to measure levels of
  thyroid hormones.
• TSH (thyroid stimulating hormone) level is
  usually low
• T3 and free T4 levels are usually high
• Treatment
• Antithyroid medications
• Radioactive iodine
• Surgery

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Thyroid disorder

• Hypothyroidism
• Hypothyroidism is a condition in which the
  thyroid gland does not make enough thyroid
  hormone.
• Causes
• The most common cause of hypothyroidism is
  inflammation of the thyroid gland.
• Autoimmune in which the immune system attacks
  the thyroid gland.
• Other common causes of hypothyroidism include
• Radiation treatments to the neck to treat
  different cancers
• Radioactive iodine used to treat an overactive
  thyroid.

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Hypothyroidism

• Surgical removal of part or all of the thyroid
  gland.
• Certain drugsAmiodarone.
• Symptoms,weakness,lethargy,memory loss, weight
  gain.hair loss,
• Treatment, thyroxine replacement therapy.

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Case 1

• Miss SM is 25 year old with Grave disease.She was
  treated with carbimazole but developed severe
  rash, so the drug was withdrawn.Rash also occured
  with propylthiouracil.She is thyrotoxic with
  blood pressure 160/60.Pulse rate 110 bpm and very
  large thyroid gland.Lab test shows elevated
  T4.Surgery is indicated.
• What are the indications for surgery?
• What therapy would you recommend to alleviate
  some of her symptoms?
• What preoperative thyroid preparation is needed?
• What postoperative complications are associated
  with thyroidectomy

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Answer

• 1-Surgery is the treatment of choice when
  malignancy is suspected, and when patient has
  features of local compression,as difficulty
  swallowing,for removal of goitre, (
  cosmetic),when thionamides have caused side
  effects, and when patient is pregnant.
• 2-B-blockers, relieve tremors,palpitations,
• 3-All patients should be euthyroid at time of
  surgery to avoid rapid elevation of T4 and
  precipitation of thyroid crysis.
• She should recieve Lugol solution,B blocker,
• 4-Postoperative complications, are risk of
  anaesthesia,and surgery itself.
• Hypoparathyrodism,infection and poor wound
  healing,

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Case 2

• Mr BC is 66.He has been commenced on thyroxine.He
  has a prescription for carbamazepine too , and
  FeSO4 in the morning.
• What issues should be covered when counseling Mr
  BC about his medicines?

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Answer

• There are two potential drug interactions,
• Ferrous sulphate has been shown to cause
  reduction in the effect of thyroxine in patients
  with hypothyrodism.
• So separate thyroxine and ferrous sulphate doses
  by two hours at least.
• Anticonvulsants have been reported to increase
  the metabolism of thyroid hormones, but this is
  not very important.
• Mr BC should attend for regular monitoring.
• It should be explained to him that it may be
  several weeks or months before symptoms are fully
  controlled.
• Mr BC should also be told that he may need
  lifelong therapy,it is also important to
  reinforce this when the patient has become
  asymptomatic from his thyroid disease.