Nurs 8024 module 11 - 12
Primary hypothyroidism
abnormality in the thyroid gland itself (↑TSH, ↓FT4)
Secondary hypothyroidism
hypothyroidism is due to lack of pituitary TSH (↓TSH, ↓FT4)
Drugs that cause goiter
Lithium, amiodarone, propylthiouracil, methimazole, phenylbutazone, sulfonamides,
interferon
Factors affecting levothyroxine absorption
Should be taken on an empty stomach, without other medications, supplements, or food for
1 hour, or 4 hours after the last meal
•fasting administration helps keep TSH target range
T4 Dosing Considerations - Elevated TSH
typically indicates underreplacement
•Before increasing dosage, assess for angina, diarrhea, malabsorption
•Maintenance dose should be continued w/ same brand
•slight differences in absorption
T4 requirements increase with
oral estrogen therapy
•Increase T4 dose 30% as soon as pregnancy is confirmed
what to avoid with T4 administration?
administration with binding agents
•iron, aluminum hydroxide antacids, calcium supplements, soy milk; or with bile acid-binding
resins (cholestyramine)
hyperthyroidism/thyrotoxicosis
Hyperthyroidism is a hypermetabolic state resulting from excess thyroid hormone
•Affects 2% of women and 0.2% of men in their lifetimes
,Expected labs in thyrotoxicosis
Suppressed TSH + elevated thyroid hormone levels (↑Free T4, ↑Free T3)
Triad of Grave's Disease
1. Hyperthyroidism
2. Ophthalmopathy
3. Dermopathy
Medication tx of hyperthyroidism
Thioamides
(Methimazole, Propylthiouracil(PTU)
Iodides
symptomatic management of hyperthyroidism
Beta-Blockers
Thiomides MOA
First line RX
inhibit thyroid peroxidase reactions, iodine organification, and peripheral conversion of T 4to
T
Thiomides pharmacokinetics
Oral, delayed onset (3-4wks)
Thioamides ADE
Nausea, GI symptoms, rash, hypothyroidism
•Serious side effects rare: agranulocytosis, hepatitis, vasculitis, aplastic anemia (0.2 - 0.5%)
Iodides MOA
Inhibits iodine organification & hormone release
•reduces size & vascularity of thyroid gland
Iodides Pharmicokinetics
Oral, rapid onset of activity (within 2-7 days)
,Iodide ADE
Rare- avoid in pregnancy
advantages of thionamides
Chance of permanent remission
Some patients avoid permanent hypothyroidism
Lower initial cost
Disadvantages of THionamides
Minor side effects: rash, hives, arthralgias, transient granulocytopenia, gastrointestinal
symptoms
Major side effects: agranulocytosis, vasculitis (lupus-like syndrome), hepatitis
Risk of fetal goiter, hypothyroidism, and birth defects if pregnant
Requires more frequent monitoring
B-Blocker use for thyroid s/s
Provide symptom relief- helps to control adrenergic manifestations •Propranolol inhibits
peripheral conversion of T 4to T 3
•Propranolol- drug of choice
•Can use others... Atenolol, metoprolol
•Caution with CHF, asthma
Pregnancy considerations with hyperthyroidism
Almost solely caused by Graves' disease
•Preferred Rx - treatment with 131 I prior to pregnancy
•PTU during 1st trimester, (MMI assoc w/ fetal abn)
•Subtotal thyroidectomy in 2nd trimester is an option
Pregnancy considerations with hypothyroidism
Adequate levothyroxine essential for early fetal brain development
, •↑ levothyroxine dosage (30-50%) common
Amioderone
contains 37 percent iodine
•Can have multiple effects on thyroid function
Amiodarone and hyperthyroidism
2 types of amiodarone-induced thyrotoxicosis •Types differ in pathogenesis, management,
and outcome
•Type 1: increased synthesis of thyroid hormone •usually in patients with a preexisting
nodular goiter
•Type 2, there is excess release of T4 and T3 due to a destructive thyroiditis
Amiodarone and hypothyroidism
via antithyroid action of iodine
•especially in patients w/ preexisting thyroid disease
Eye manifestations of hyperthyroidism
-Blurred or double vision
-Eye fatigue
-Corneal ulcers/infection
-Increased tears
-Red conjunctiva
-Eyelid retraction/lag/globe lag
-Wide eye staring appearance
Most common cause of hyperthyroidism
Grave's disease (autoimmune)
Other causes of hyperthyroidism
Toxic nodular goiter
Thyroiditis
Excess iodine intake
Pituitary tumors
Thyroid cancer
Most common cause of hypothyroidism
Primary hypothyroidism
abnormality in the thyroid gland itself (↑TSH, ↓FT4)
Secondary hypothyroidism
hypothyroidism is due to lack of pituitary TSH (↓TSH, ↓FT4)
Drugs that cause goiter
Lithium, amiodarone, propylthiouracil, methimazole, phenylbutazone, sulfonamides,
interferon
Factors affecting levothyroxine absorption
Should be taken on an empty stomach, without other medications, supplements, or food for
1 hour, or 4 hours after the last meal
•fasting administration helps keep TSH target range
T4 Dosing Considerations - Elevated TSH
typically indicates underreplacement
•Before increasing dosage, assess for angina, diarrhea, malabsorption
•Maintenance dose should be continued w/ same brand
•slight differences in absorption
T4 requirements increase with
oral estrogen therapy
•Increase T4 dose 30% as soon as pregnancy is confirmed
what to avoid with T4 administration?
administration with binding agents
•iron, aluminum hydroxide antacids, calcium supplements, soy milk; or with bile acid-binding
resins (cholestyramine)
hyperthyroidism/thyrotoxicosis
Hyperthyroidism is a hypermetabolic state resulting from excess thyroid hormone
•Affects 2% of women and 0.2% of men in their lifetimes
,Expected labs in thyrotoxicosis
Suppressed TSH + elevated thyroid hormone levels (↑Free T4, ↑Free T3)
Triad of Grave's Disease
1. Hyperthyroidism
2. Ophthalmopathy
3. Dermopathy
Medication tx of hyperthyroidism
Thioamides
(Methimazole, Propylthiouracil(PTU)
Iodides
symptomatic management of hyperthyroidism
Beta-Blockers
Thiomides MOA
First line RX
inhibit thyroid peroxidase reactions, iodine organification, and peripheral conversion of T 4to
T
Thiomides pharmacokinetics
Oral, delayed onset (3-4wks)
Thioamides ADE
Nausea, GI symptoms, rash, hypothyroidism
•Serious side effects rare: agranulocytosis, hepatitis, vasculitis, aplastic anemia (0.2 - 0.5%)
Iodides MOA
Inhibits iodine organification & hormone release
•reduces size & vascularity of thyroid gland
Iodides Pharmicokinetics
Oral, rapid onset of activity (within 2-7 days)
,Iodide ADE
Rare- avoid in pregnancy
advantages of thionamides
Chance of permanent remission
Some patients avoid permanent hypothyroidism
Lower initial cost
Disadvantages of THionamides
Minor side effects: rash, hives, arthralgias, transient granulocytopenia, gastrointestinal
symptoms
Major side effects: agranulocytosis, vasculitis (lupus-like syndrome), hepatitis
Risk of fetal goiter, hypothyroidism, and birth defects if pregnant
Requires more frequent monitoring
B-Blocker use for thyroid s/s
Provide symptom relief- helps to control adrenergic manifestations •Propranolol inhibits
peripheral conversion of T 4to T 3
•Propranolol- drug of choice
•Can use others... Atenolol, metoprolol
•Caution with CHF, asthma
Pregnancy considerations with hyperthyroidism
Almost solely caused by Graves' disease
•Preferred Rx - treatment with 131 I prior to pregnancy
•PTU during 1st trimester, (MMI assoc w/ fetal abn)
•Subtotal thyroidectomy in 2nd trimester is an option
Pregnancy considerations with hypothyroidism
Adequate levothyroxine essential for early fetal brain development
, •↑ levothyroxine dosage (30-50%) common
Amioderone
contains 37 percent iodine
•Can have multiple effects on thyroid function
Amiodarone and hyperthyroidism
2 types of amiodarone-induced thyrotoxicosis •Types differ in pathogenesis, management,
and outcome
•Type 1: increased synthesis of thyroid hormone •usually in patients with a preexisting
nodular goiter
•Type 2, there is excess release of T4 and T3 due to a destructive thyroiditis
Amiodarone and hypothyroidism
via antithyroid action of iodine
•especially in patients w/ preexisting thyroid disease
Eye manifestations of hyperthyroidism
-Blurred or double vision
-Eye fatigue
-Corneal ulcers/infection
-Increased tears
-Red conjunctiva
-Eyelid retraction/lag/globe lag
-Wide eye staring appearance
Most common cause of hyperthyroidism
Grave's disease (autoimmune)
Other causes of hyperthyroidism
Toxic nodular goiter
Thyroiditis
Excess iodine intake
Pituitary tumors
Thyroid cancer
Most common cause of hypothyroidism
