Read Mosby's 2014 Nursing Drug Reference Online
Authors: Linda Skidmore-Roth
Canada only Side effects:
italics
= common;
bold
= life-threatening
Nurse Alert
See
Appendix B
(lee-voe-thye-rox′een)
Eltroxin
, Levothroid, Levoxyl, Synthroid, Tirosint, Unithroid
Func. class.:
Thyroid hormone
Chem. class.:
Levoisomer of thyroxine
Do not confuse:
Synthroid
/Symmetrel
Increases metabolic rate; controls protein synthesis; increases cardiac output, renal blood flow, O
2
consumption, body temp, blood volume, growth, development at cellular level via action on thyroid hormone receptors
Hypothyroidism, myxedema coma, thyroid hormone replacement, thyrotoxicosis, congenital hypothyroidism, some types of thyroid cancer, pituitary TSH suppression
Adrenal insufficiency, recent MI, thyrotoxicosis, hypersensitivity to beef, alcohol intolerance (inj only)
Black Box Warning:
Obesity treatment
Precautions:
Pregnancy (A), breastfeeding, geriatric patients, angina pectoris, hypertension, ischemia, cardiac disease, diabetes
• Adult ≤50 yr:
PO
1.7 mcg/kg/day, 6-8 wk, average dose 100-200 mcg/day; max 200 mcg/day
IM/IV
50-100 mcg/day as single dose or 50% of usual oral dosage
• Adult >50 yr without heart disease or <50 yr with heart disease:
PO
25-50 mcg/day, titrate q6-8wk
• Adult >50 yr with heart disease:
PO
12.5-25 mcg/day, titrate by 12.5-25 mcg q6-8wk
• Child >12 yr:
PO
2-3 mcg/kg/day as single dose in
AM
• Child 6-12 yr:
PO
4-5 mcg/kg/day as single dose in
AM
• Child 1-5 yr:
PO
5-6 mcg/kg/day as single dose in
AM
• Child 6-12 mo:
PO
6-8 mcg/kg/day as single dose in
AM
• Child to 6 mo:
PO
8-10 mcg/kg/day as single dose in
AM
• Adult:
IV
200-500 mcg, may increase by 100-300 mcg after 24 hr; give oral medication as soon as possible
• Adult:
PO
1 mcg/kg/day may be sufficient
Available forms:
Powder for inj 200, 500 mcg/vial; tabs 25, 50, 88, 100, 112, 125, 137, 150, 175, 200, 300 mcg; cap (liquid filled) 13, 25, 50, 75, 88, 100, 112, 125, 137, 150 mcg
•
In
AM
if possible as single dose to decrease sleeplessness; at same time each day to maintain product level; take on empty stomach
•
Only for hormone imbalances; not to be used for obesity, male infertility, menstrual conditions, lethargy
•
Lowest dose that relieves symptoms; lower dose to geriatric patients and for those with cardiac diseases
•
Crush and mix with water; nonsoy formula or breast milk for infants, children
•
Separate antacids, iron, calcium products by 4 hr
•
IV after diluting with provided diluent 500 mcg/5 ml, 200 mcg/2 ml; shake; give through
Y
-tube or 3-way stopcock; give ≤100 mcg/1 min; do not add to IV inf
•
Considered to be incompatible in syringe with all other products
CNS:
Anxiety, insomnia, tremors
, headache,
thyroid storm,
excitability
CV:
Tachycardia, palpitations, angina, dysrhythmias
, hypertension,
cardiac arrest
GI:
Nausea, diarrhea, increased or decreased appetite, cramps
MISC:
Menstrual irregularities, weight loss, sweating, heat intolerance, fever, alopecia, decreased bone mineral density
Half-life euthyroid 6-7 days, hypothyroid 9-10 days, hyperthyroid 3-4 days, distributed throughout body tissues
PO:
Onset 3-5 days, peak 6-8 wk, duration 1-3 wk
IV:
Onset 6-8 hr, peak 24 hr, duration unknown
Increase:
cardiac insufficiency risk—EPINEPHrine products
Increase:
effects of anticoagulants, sympathomimetics, tricyclics
Decrease:
levothyroxine absorption—bile acid sequestrants, orlistat, ferrous sulfate
Decrease:
levothyroxine effect—estrogens, antacids, sucralfate, aluminum, magnesium, calcium, iron, rifampin, rifabutin
Decrease:
thyroid hormone effect—soy
Increase:
CPK, LDH, AST, blood glucose
Decrease:
thyroid function tests
•
B/P, pulse periodically during treatment
•
Weight daily in same clothing, using same scale, at same time of day
•
Height, growth rate of child
•
T
3
, T
4
, FTIs, which are decreased; radioimmunoassay of TSH, which is increased; radio uptake, which is increased if patient receiving too low a dose of medication
•
Patient may require decreased anticoagulant; check for bleeding, bruising
•
Increased nervousness, excitability, irritability, which may indicate too high a dose of medication, usually after 1-3 wk of treatment
•
Cardiac status: angina, palpitation, chest pain, change in VS
•
Storage in tight, light-resistant container; sol should be discarded if not used immediately
•
Withdrawal of medication 4 wk before RAIU test
•
Therapeutic response: absence of depression; increased weight loss, diuresis, pulse, appetite; absence of constipation, peripheral edema, cold intolerance; pale, cool, dry skin; brittle nails, alopecia, coarse hair, menorrhagia, night blindness, paresthesias, syncope, stupor, coma, rosy cheeks
•
That hair loss will occur in child, is temporary; that hypothyroid child will show almost immediate behavior/personality change
•
To report excitability, irritability, anxiety, which indicate overdose
•
Not to switch brands unless approved by prescriber
•
That product may be discontinued after giving birth; that thyroid panel should be evaluated after 1-2 mo
•
That product is not to be taken to reduce weight
•
To avoid OTC preparations with iodine; to read labels; to separate antacids, iron, calcium products by 4 hr
•
To avoid iodine-rich food, iodized salt, soybeans, tofu, turnips, high-iodine seafood, some bread
•
That product is not a cure but controls symptoms; that treatment is lifelong, full effect may take up to 6 wk
Canada only Side effects:
italics
= common;
bold
= life-threatening
Nurse Alert
(lye′doe-kane)
LidoPen Auto-Injector, Xylocaine, Xylocard
Func. class.:
Antidysrhythmic (Class Ib)
Chem. class.:
Aminoacyl amide