NAME OF DRUG
levo-thyroxine sodium

CLASSIFICATION

Thyroid hormone

ALTERNATE NAME

SYNTHROID

 INDICATIONS

• reversal of myxedema coma or stupor without concomitant severe heart disease
• replacement therapy in primary hypothyroidism if patient cannot receive oral therapy for greater than 7-10 days

 RECONSTITUTION AND STABILITY

• powder is stable at room temperature
• reconstitute with diluent provided or 5 mL NS to provide a concentration of 0.1 mg/mL; shake well to ensure complete mixing
• use solution immediately after reconstitution; discard unused portion

 COMPATIBILITY

• DO NOT ADD RECONSTITUTED SOLUTION TO INTRAVENOUS FLUIDS
• incompatible with any other drug

 ROUTES OF ADMINISTRATION

• IV direct - preferred route
  • 0.1 mg or fraction over 1 minute
• IM - not recommended as absorption is unpredictable

 VH & HSC ADMINISTRATION POLICY

E - May be administered by direct IV route by nurses on general nursing units provided a venous access has been established, and according to policies and recommendations stated in this manual.

 DOSAGE

Adults:

Myxedema coma:

• Initial dose: 0.2-0.5 mg IV; if response is not optimum by the second day, an additional 0.1-0.3 mg IV may be given; repeat as indicated
• Usual maintenance dose: 50-200 mcg IV daily until condition stabilizes and drug can be given orally

Primary hypothyroidism:

• 1/2-1/3 oral dosage 2-3 times weekly or adjusted according to response

 POTENTIAL HAZARDS OF PARENTERAL ADMINISTRATION

IMPORTANT IMPLICATIONS

• adverse effects include:  chest pain, tachycardia, hypertension, muscle cramps, nervousness, perspiration
• adrenocortical insufficiency, if present, must be corrected before administration, or acute adrenal crisis and death may result
• use with caution in diabetes mellitus and cardiovascular disease
• increases the metabolic rate; dosage adjustments may be required for anticoagulants, antidepressants, oral hypoglycemics, insulin, digoxin
• onset of action is slow - 5-8 hours (24 hours may be necessary to note full effects)
• contraindicated after myocardial infarction and thyrotoxicosis
• thyroid function status should be monitored

Rev. July 1987