الاسم : سعد بن محمد نور بن محمد ولي الرقم الجامعي : التخصص : معيد بكلية الصيدلة قسم الأدوية Pharmacology استخدام الحاسب لتقديم محاضرة في موضوع مختص بالبوربوينت

The thyroid is one of the largest endocrine glands. The thyroid gland is found in the neck, below (inferior to) the thyroid cartilage (which forms the laryngeal prominence, or 'Adam's Apple').

The functional unit of the thyroid is the follicle or acinus. Each follicle consists of a single layer of epithelial cells around a cavity, the follicle lumen, which is filled with a thick colloid containing thyroglobulin.

The thyroid gland secretes three main hormones: 1- thyroxine (T 4 ) 2- triiodothyronine (T 3 ) 3- calcitonin.

The main steps in the synthesis, storage and secretion of thyroid hormone are as follow:  uptake of plasma iodide by the follicle cells.  oxidation of iodide and iodination of tyrosine residues of thyroglobulin.  secretion of thyroid hormone.

1- Hyperthyrodism - Toxic goiter:enlarged thyroid gland. - Thyrotoxicosis:Increase the body's metabolic rate and in the hands and jerk Increase in appetite. - Grave's disease:is a disease of autoimmune disorder, which affects the thyroid gland and cause hyperthyroidism. And is one of the most common type of overactive thyroid prevalent.

Thioamides Such as:carbimazole, methimazole and propylthiouracil Use: To the treat of thyperthyroidism Mechanism of action: The major action is to prevent hormone synthesis by inhibiting the thyroid peroxidase-catalyzed reactions and blocking iodine organification. Side effect: Rashes are more common (2-25%), and other symptoms, such as headaches, nausea, jaundice and pain in the joints, can occur.

Iodide Mechanism of action: Blockade of hormone release. Side effect: Allergic reactions can occur; these include angio-oedema, rashes, drug fever, lacrimation, conjunctivitis, pain in the salivary glands and a cold-like syndrome. Use: The main uses of iodine/iodide are for the preparation of hyperthyroid subjects for surgical resection of the gland, and as part of the treatment of severe thyrotoxic crisis (thyroid storm).

Radioiodine 131 I ( iodide radio iso to ) Use: surgically or by destruction destruction of the gland by beta particles emitted by radioactive iodine (131I), Another use for this drug is the treatment of thyroid cancer. side effect: Radioiodine is best avoided in children and also in pregnant patients because of potential damage to the fetus. There is a theoretical risk of thyroid cancer following the treatment.

Propranolol Mechanism of action: The β-adrenoceptor antagonist. propranolol, are not antithyroid agents as such, but they are useful for decreasing many of the signs and symptoms of hyperthyroidism-the tachycardia, dysrhythmias.

:2- Hypothyrodism -Myxedema:in adult due to iodine deficiency sipmle goiter:deficiency of iodine in diet. -cretinism:in childhood due to Endemic extreme iodine deficiency and sporadic defective hormone synthesis.

Levothyroxine Use: It is the drug choice for suppressent of the hormone. Side effect: nervousness, heart palpitations and tachycardia, intolerance to heat, and unexplained weight loss.

Liothyronine Side effect: precipitating angina pectoris, cardiac dysrhythmias or even cardiac failure “ cardiac toxicity ” Use: To increase secreation of thyroid.

it is located behind the thyroid gland in the neck. Parathyroid hormone is the most important endocrine regulator of calcium and phosphorus concentration in extracellular fluid.

if calcium ion concentrations in extracellular fluid fall below normal, Parathyroid hormone stimulating at least three processes:  Mobilization of calcium from bone: parathyroid hormone is to stimulate osteoclasts to resorb (breakdown) bone mineral, liberating calcium into blood.  Enhancing absorption of calcium from the small intestine: Parathyroid hormone stimulates calcium absorption with help of vitamin D  reabsorption of calcium from urine: parathyroid hormone is affected by stimulating tubular reabsorption of calcium.

1- Hyperparathyrodism: - Increas secrete extra PTH and blood calcium rises. - extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer. 2- Hypoparathyrodism:  do not have enough PTH.  blood will have too little calcium and too much phosphorous.

: Saline Diuresis - rapid reduction of serum calcium - the initial infusion of 500–1000 mL/h of saline to reverse the dehydration and restore urine flow can by itself substantially lower serum calcium.

: Bisphosphonates Pamidronate, and zoledronate, have been approved for the treatment of hypercalcemia of malignancy for this indication.

: Calcitonin Calcitonin by itself seldom restores serum calcium to normal, and refractoriness frequently develops. Calcimar (salmon calcitonin) is available for parenteral and nasal administration.

: Gallium Nitrate It is used in hypercalcemia of malignancy and is undergoing trials for the treatment of advanced Paget's disease.

: Plicamycin (Mithramycin) - Because of its toxicity, plicamycin (mithramycin) is not the drug of first choice for the treatment of hypercalcemia. - The most dangerous toxic effect is sudden thrombocytopenia followed by hemorrhage.

: Phosphate - Giving intravenous phosphate is probably the fastest and surest way to reduce serum calcium, but it is a hazardous procedure if not done properly - The risks of intravenous phosphate therapy include sudden hypocalcemia, acute renal failure, and hypotension.

Calcium A number of calcium preparations are available for intravenous, intramuscular, and oral use. Calcium gluceptate, calcium gluconate and calcium chloride are available for intravenous therapy.

Vitamin D (calcitriol) - vitamin D itself for long-term therapy. - it is capable of raising serum calcium within 24– 48 hours.

   Book : Basic And Clinical Pharmacology Book : Basic And Clinical Pharmacology