Difficulty in recruiting subjects.

This study is designed to investigate whether the treatment of non-anemic iron deficiency with intervenous iron sucrose will result in decreased symptom reporting and improved cardiovascular indices in adolescents (age 12-21) with Postural Orthostatic Tachycardia Syndrome (POTS).

Postural orthostatic tachycardia syndrome (POTS) is characterized by an exaggerated heart rate response to the standing position in a patient with symptoms of orthostatic intolerance. It is likely a heterogeneous disorder representing a common manifestation of a number of possible underlying derangements such as impaired sympathetically mediated vasoconstriction, excessive sympathetic drive, volume dysregulation and deconditioning. While the actual prevalence of POTS is unknown, it has been estimated to affect at least 500,000 individuals in the United States. It predominately affects young individuals, and particularly women.

The prevalence of iron deficiency in adolescents with POTS has been reported to be greater than that expected in the general adolescent population. The use of intravenous iron sucrose has been shown to be a safe and effective therapy for correcting iron deficiency in children and adolescents. Anecdotal experience at our clinic has demonstrated an immediate reduction in self-reported orthostatic symptoms in several patients diagnosed with POTS following the administration of intravenous iron sucrose for iron deficiency.

This study is a randomized, double blind, placebo-controlled study to assess the efficacy of a single iron sucrose infusion in adolescents with non-anemic iron deficiency and POTS. Subjects will be screened at outpatient clinic visit appointments. Interested qualified subjects will be consented and offered participation in this trial. Once consent and assent (for patients less than 18 years of age) has been obtained, subjects will be randomized to either treatment or placebo group. Subjects will participate in two on site study visits. During the first visit subjects will complete baseline laboratory studies, tilt table test and study questionnaires. Subjects will then receive the intervention study drug or placebo. The second study visit will occur 7 days + 2 days from the first study visit. During the second study visit subjects will repeat laboratory studies, tilt table test and study questionnaires. Follow up questionnaires will be sent to all subjects six months following the initial study visit.

Inclusion criteria

• aged 12-21 years
• chronic (>3 months)symptoms of orthostatic intolerance (including but not limited to lightheadedness, syncope, headache, fatigue, weakness, sweating, nausea and palpitations)
• symptomatic orthostatic heart rate increase of greater than or equal to 40 beats per minute during a 10 minute 70 degree head up tilt study
• presence of non-anemic iron deficiency, defined as serum ferritin level less than or equal to 20 ug/L with normal hemoglobin

Exclusion criteria

• orthostatic hypotension within 3 minutes of 70 degree head up tilt
• pregnant or lactating females
• presence of other organ failure or systemic illness that can affect autonomic function
• concurrent medication therapy with anticholinergic, alpha-adrenergic antagonists, beta-adrenergic antagonists unless medication is held for five half-lives prior to study
• laboratory evidence of anemia or iron overload
• personal history of hematochromatosis or first degree relative with hematochromatosis
• known sensitivity to Venofer (TM) or other intravenous iron preparations

Six months

The study was terminated early due to difficulty in recruiting subjects.