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Pharmacokinetics and pharmacodynamics of orally administered clonidine: a model-based approach

R H Klein1, R Alvarez-Jimenez, R N Sukhai

  • 1Centre for Human Drug Research, Leiden University Medical Center, NL-2300 RC Leiden, The Netherlands. r.h.klein@lumc.nl

Hormone Research in Paediatrics
|June 6, 2013
PubMed

Insights

The oral clonidine test for growth hormone (GH) deficiency in children showed higher than necessary clonidine levels. A lower dose may reduce side effects while maintaining diagnostic accuracy for GH deficiency.

Area of Science:

  • Pediatric Endocrinology
  • Pharmacology
  • Diagnostic Testing

Background:

  • The oral clonidine test diagnoses growth hormone (GH) deficiency in children.
  • This test can cause bradycardia, hypotension, and sedation.
  • Serum clonidine levels were not previously measured during this test.

Purpose of the Study:

  • To assess serum clonidine levels during the oral clonidine test in children.
  • To explore the relationship between clonidine concentrations and clinical effects.
  • To determine if current dosing is optimal for diagnosing GH deficiency.

Main Methods:

  • 40 children underwent the oral clonidine test for suspected GH deficiency.
  • Blood samples were collected to measure clonidine and GH levels.
  • Vital signs and sedation scores were monitored for 210 minutes post-dose.

Main Results:

  • Peak clonidine levels reached 0.846 ± 0.288 ng/ml at 1 hour, with slow decline.
  • Significant interindividual variation in serum clonidine levels was observed.
  • Blood pressure decreased (systolic 12.8%, diastolic 19.7%) and heart rate dropped (8.4%), with moderate sedation.

Conclusions:

  • Observed clonidine concentrations exceeded model-based predictions for efficacy.
  • A lower clonidine dose might be sufficient for diagnosing GH deficiency.
  • Reducing the clonidine dose could minimize adverse effects like hypotension and sedation.
Abstract

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