Pharmacokinetics of pyridostigmine in a child with postural tachycardia syndrome.

Abstract

Pyridostigmine has been proposed for the treatment of postural orthostatic tachycardia syndrome in adults at a dose of 60 mg twice daily, but no dosing recommendation exists for children. With the approval of our local ethics board, we tested the pharmacokinetics of pyridostigmine in 6 children with myasthenia and a pediatric index patient with severe postural orthostatic tachycardia syndrome whose condition failed all conventional therapy and who had developed significant postural hypertension. Pyridostigmine was quantified by using a validated, semiautomated, and specific high-performance liquid chromatography/tandem mass spectrometry assay in combination with online column-switching extraction and turbo electrospray ionization. The patient with postural orthostatic tachycardia syndrome showed a dose-dependent favorable response to oral pyridostigmine. Pharmacokinetic evaluation revealed a short half-life of 2.29 hours, similar to the 2.0 +/- 0.63 hours in the patients with myasthenia. The patient with postural orthostatic tachycardia syndrome has subsequently been treated at a dose of 45 mg in the morning, 30 mg at lunchtime, and 15 mg at bedtime; after 9 months, there has been persistent positive effect and without additional blood pressure medication. No major adverse effects occurred. Pyridostigmine has been a safe and effective treatment modality for this child with postural orthostatic tachycardia syndrome. The short half-life suggests that dosing 3 times per day is preferable.

• Authors: Guido Filler, Robert M Gow, Renisha Nadarajah, Pierre Jacob, Gillian Johnson, Yan-Ling Zhang, Uwe Christians
• Journal: Pediatrics (Pediatrics) Vol. 118 Issue 5 Pg. e1563-8 (Nov 2006) ISSN: 1098-4275 [Electronic] United States
• PMID: 17015495 (Publication Type: Case Reports, Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Cholinesterase Inhibitors
• Pyridostigmine Bromide

Topics

• Adolescent
• Child
• Child, Preschool
• Cholinesterase Inhibitors (pharmacokinetics)
• Female
• Humans
• Male
• Posture
• Pyridostigmine Bromide (pharmacokinetics)
• Syndrome
• Tachycardia (metabolism)