Protirelin

Hypothalamic Releasing Hormone / Thyrotropin Releasing Hormone (TRH) AnalogRx: PrescriptionCompound: Approved

Also known as: Lopremone, pGlu-His-Pro-NH2, Relefact TRH, Thypinone, Thyrotropin-releasing hormone, TRH

Educational Only — Not medical advice. Consult a qualified clinician before using any peptide.

Summary

Protirelin (synthetic TRH) is a tripeptide (pyroglutamyl-histidyl-prolinamide) used diagnostically to assess pituitary TSH reserve and to differentiate causes of hypothyroidism. It stimulates TSH and prolactin secretion from the anterior pituitary. It has been used clinically as the TRH stimulation test and was also investigated for neurological conditions.

Mechanism of Action

Synthetic tripeptide analog of endogenous thyrotropin-releasing hormone (TRH); binds TRH receptors in the anterior pituitary to stimulate release of thyroid-stimulating hormone (TSH) and prolactin; also has direct CNS effects via TRH receptors in the brain

Routes of Administration

Intravenous

Goals & Uses

  • Diagnostic assessment of pituitary TSH reserveEndocrine DiagnosticsHigh
  • Differentiation of hypothalamic vs. pituitary hypothyroidismEndocrine DiagnosticsHigh
  • Neuroprotection / CNS disorders (investigational)NeurologyLow
  • Prolactin secretion assessmentEndocrine DiagnosticsModerate

Contraindications

  • Known hypersensitivity to protirelinAllergy/ImmunologyHigh
  • Seizure disordersNeurologyModerate
  • Coronary artery disease (unstable)CardiovascularHigh
  • Myocardial infarction (recent)CardiovascularHigh

Adverse Effects

  • Urge to urinateUrologicalCommon
  • HeadacheNeurologicUncommonPain in the head or upper neck
  • Transient hypertensionCardiovascularUncommon
  • NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
  • Flushing / warmth sensationVascularCommon
  • Anxiety / lightheadednessNeurologicalUncommon

Drug Interactions

  • Dopamine agonists (e.g., levodopa, bromocriptine)Moderate
  • CorticosteroidsModerate
  • Antidepressants (tricyclics, SSRIs)Low
  • Levothyroxine / thyroid hormoneHigh

Population Constraints

  • PregnancyReproductive SafetyRelative
  • Elderly patients with cardiovascular diseaseCardiovascularRelative
  • Pediatric patientsAgeRelative
  • Patients with adrenal insufficiencyEndocrineRelative

Regulatory Status

  • European UnionApprovedApproved: Diagnostic test for thyroid and pituitary functionAvailable in several EU countries (e.g., Germany as Relefact TRH) for diagnostic endocrine testing
  • United StatesApprovedApproved: Diagnostic assessment of thyroid function (TRH stimulation test), Adjunctive assessment of pituitary thyrotroph responsivenessThypinone previously marketed; some branded products discontinued but compound retains approved status for diagnostic use
  • United KingdomApprovedApproved: TRH stimulation test for thyroid and pituitary assessmentLicensed for diagnostic use; product availability may vary

Approved in the US (Thypinone, Relefact TRH) for diagnostic use; some formulations have been discontinued. Still used in certain jurisdictions for diagnostic endocrine testing. Not for therapeutic replacement use in hypothyroidism.

Evidence & Sources

No sources recorded yet.

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