Pharmacology Final

more active than T4

inactive

longer duration of action than T3

70-195 ng/dl

5-12 mcg/dl

0.3-5.0 mIU/L

24-34%

4 to 11

• T3
• T4
• T3U
• Free Thyroxine index

TSH

• T3
• T4
• T3U
• Free thyroxine index

TSH

• grave's disease
• congenital thyrotoxicosis
• transient hyperthyroidism
• metastatic thyroid carcinoma

used in treatment of hypothyroidism

should not be used for weight loss

• increases response to oral anticoagulation therapy
• effects of digitalis glycosides may be reduced by levothyroxine

• treatment of hypothyroidism
• can be used in pt allergic to desiccated thyroid or thyroid extract derived from pork or beef

rare

• thyroid hormones increase catabolism of vitamin K dependant clotting factors
• may cause increases in insulin or oral hypoglycemic requirements
• estrogens increase serum thyroxine binding globulin decreasing levothyroxine

• leads to increased receptor sensitivity and enhanced anti-depresant activity
• transient cardiac arrhythmias have been observed

TH increases metabolic rate which requires an increase in digitalis dosing

when administered together may cause hypertension and tachycardia

TH increases adrenergic effect of catecholamines such as epinephrine and norepinephrine

• hyperthyroidism
• may lead to remission of the disease
• used when thyroidectomy is contraindicated

• Agranulocytosis
• Granulocytopenia
• Thrombocytopenia

• Anticoagulants
• Beta adrenergic blocking agents
• Digitalis glycosides
• Theophylline

activity of anticoag may be potentiated by methimazole

When pt. has hyperthyroidism, they will have increased clearance of beta blockers. When their thyroid is fixed they will require a dose reduction.

Digitalis levels increased when pt returns to euthyroid

theophylline clearance may decrease when hyperthyroid pt becomes euthyroid. pt will require a dose reduction.