Parenteral Manual


Disclaimer: Official controlled document is the CHEO online copy. It is the responsibility of user to ensure that any paper copy version is the same as the online version before use.

Alternate Name(s): 
RELEFACT , Thyrotropin Releasing Hormone , TRH
Diagnostic Agent, Thyroid Function
Original Date: 
January 2008
Revised Date: 
September 2011
  • Diagnostic agent for disorders of the thyroid or pituitary gland
Reconstitution and Stability: 
  • Available in 500 mcg/mL solution
  • Stable at room temperature
  • Discard unused portion

-Solutions Compatible:  NS


(For approved routes of administration by nursing personnel, refer to Policy for the Administration of Intravenous Medications.)

IV Direct

YES  -over 15 - 30 seconds (may be injected into tubing of running NS infusion)


IV Intermittent Infusion NO
IV Continuous Infusion NO

(For neonatal dosages, refer to Neonatal IV Drug Manual.)



  • Diagnostic test: 7 mcg/kg   (up to max 500 mcg) IV


  •  Diagnostic test: 200 to 500 mcg IV



Potential hazards of parenteral administration: 
  • Flushing, chest tightness, hypotension or hypertension; continuous blood pressure monitoring is required
  • Lightheadedness, anxiety, seizures, drowsiness, headache
  • Nausea, abdominal discomfort, metallic taste in the mouth, urinary urgency, diaphoresis
  • Patient should be supine before, during and at least 15 minutes after the injection
  • Blood samples should be drawn immediately before the injection and at 20 to 30 minutes after injection.  Samples may have to repeated 45 to 60 minutes after injection to detect possible delayed response.
  • Use with caution in patients with cardiac disease, hypertension, renal insufficiency, or bronchial asthma
  • Caffeine enhances TRH activity and therefore patients should avoid food and beverages containing this for 12 to 14 hours before the test
  • Medications that may interfere with testing results: exogenous estrogens, glucocorticoids, levodopa, lithium, thyroid hormones, antithyroid agents, theophylline.

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