NU 516 Study Guide for Unit 4 Exam 2025

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Study Guide for Unit 4 Exam


Treatments for hypothyroidism:
 Familiarize yourself with TSH levels, what labs are important, what to do when TSH is low or
elevated
o Serum values for thyroid function (pg 713)
o Serum TSH (pg 713)
 Most sensitive measurement for hypothyroid – anterior pituitary sensitive to
changes in TH levels
 Very small changes in T3 & T4  big rise in TSH
 Used to determine primary from secondary hypothyroid
 High – primary
o thyroidal
 Low – secondary
o Anterior pituitary dysfunction
o Serum T4 (pg 713)
 Monitor therapy & screen for thyroid dysfunction
o Serum T3 (pg 713)
 Dx hyperthyroid (will rise sooner than T4)
 Monitor TH therapy
 Review hypothyroidism in neonates – how is this treated? (pg 714)
o If started w/I few days of birth—development will be normal, but if delayed, some
permanent disability will be evident
o In all children… therapy should last for 3 years & then stopped for 4 weeks
 Obj: determine if transient or permanent
 If TSH increases (TH production is low) – deficiency is permanent
 TSH & T4 normalize – transient.. no need to further treat
 Review dosing in adults and elderly (pg 716)
 What drugs interact with levothyroxine – what do you do to adjust the medication?
o See below & pg 715-716
 Patient education regarding pregnancy and hypothyroidism
o Most impact during 1st trimester
o Need for increased dosage begins weeks 4-8 gestation, levels off around week 16, then
remains steady

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o Some ppl increase T4 dosage by 30%
o Monitor TSH
 What is the difference between levothyroxine and synthroid? – currently being debated (pg 716) –
if switch is made, retest serum TSH in 6 weeks
o Levothyroxine (T4) (pg 715)
 Absorption reduced by food – take in AM on empty stomach
 No need to give T3 w/ b/c much of dose is converted over
 Highly protein bound prolonged ½ life
 Steady long time dosing
 Takes 1 month to reach plateau
 Therapeutic uses
 All hypothyroid: congenital hypothyroid, myxedema coma, simple goiter,
primary hypothyroid, hypothyroid from insufficient TSH & TRH, maintain
hormones following thyroid surgery, irradiation, treatment w/ antithyroid
drugs
 NOT for obesity treatment
 Adverse effects
 Acute OD: thyrotoxicosis
o Tachycardia, angina, tremor, nervous, insomnia, hyperthermia, heat
intolerance, sweating
 Chronic OD: bone loss, AFIB, fractures
 Drug interactions
 Drugs that reduce absorption – separate by 4 hrs
o H2 receptor blockers (cimetidine, Tagamet)
o PPI (prevacid)
o Sucralfate (Carafate)
o Cholestyramine (Questran)
o Colestipol (Colestid)
o Alum containing antacids (Maalox, Mylanta)
o Calcium supplments (Tums)
o Iron supplements
o Mag salts
o Orlistat (Xenical)
 Drugs that accelerate metabolism

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o Phenytoin (Dilantin)
o Carbamazepine (tegretol, carbatrol)
o Rifampin
o Sertraline (Zoloft)
o Phenobarbital
 Warfarin
o Levothyroxine accelerates degradation of vit K clotting factors 
warfarin effects are enhanced
 So need to decrease warfarin dose
 Catecholamines
o TH increase cardiac responsiveness to catecholamines  increased
risk of dysrhythmias
 Increase the requirements for insulin and dig
 Admin
 PO – 30-60 min before eating
 IV – myexedema coma & if cant take PO, dose should be 50% of PO dose
 Eval
 TSH normalization lags behind T3 & T4… don’t monitor until 6-8 weeks
after starting
 TSH: .5-2
 Dosage
 Lower for older adults w/ CAD
 Myexedma coma
o Also give steroids
 Congenital hypothyroid
o Adjust dose to normalize TSH & T4


Hyperthyroidism
 Review propylthiouracil – indications, SEs, patient education (pg 718)
o 2nd line treatment
o Contrasts with methimazole
 PTU  severe liver damage
 Shorter ½ life (so requires 2-3 doses)
 Less readily crosses placenta