Reviews

Evaluating and managing postural tachycardia syndrome

Author and Disclosure Information

 

References

Other agents

Midodrine is a prodrug. The active form, an alpha-1-adrenergic agonist, constricts peripheral veins and arteries to increase vascular resistance and venous return, thereby reducing orthostatic tachycardia.52 It is most useful in patients with impaired peripheral vasoconstriction (eg, neuropathic POTS) and may be less effective in those with hyperadrenergic POTS.64 Major limitations of midodrine include worsening supine hypertension and possible urinary retention.39

Because of midodrine’s short half-life, frequent dosing is required during daytime hours (eg, 8 AM, noon, and 4 PM), but it should not be taken within 4 to 5 hours of sleep because of the risk of supine hypertension. Midodrine is typically started at 2.5 to 5 mg per dose and can be titrated up to 15 mg per dose.

Midodrine is an FDA pregnancy category C drug (adverse effects in pregnancy seen in animal models, but evidence lacking in humans). While ideally it should be avoided, we have used it safely in pregnant women with disabling POTS symptoms.

Pyridostigmine, an acetylcholinesterase inhibitor, increases cardiovagal tone and possibly sympathetic tone. It has been reported to significantly reduce standing heart rate and improve symptom burden in patients with POTS.65 However, pyridostigmine increases gastrointestinal mobility, leading to severe adverse effects in over 20% of patients, including abdominal cramps, nausea, and diarrhea.66

Droxidopa, a synthetic amino acid precursor of norepinephrine, improves dizziness and fatigue in POTS with minimal effects on blood pressure.67

Modafinil, a psychostimulant, may improve POTS-associated cognitive symptoms.4 It also raises upright blood pressure without significantly worsening standing heart rate or acute orthostatic symptoms.68

EFFECTS OF COMORBID DISORDERS ON MANAGEMENT

Ehlers-Danlos syndrome

Pharmacologic approaches to POTS should not be altered based on the presence of Ehlers-Danlos syndrome, but because many of these patients are prone to joint dislocation, exercise prescriptions may need adjusting.

A medical genetics consult is recommended for patients with Ehlers-Danlos syndrome. Although the hypermobile type (the form most commonly associated with POTS) is not associated with aortopathy, it can be confused with classical and vascular Ehlers-Danlos syndromes, which require serial aortic screening.30

Mast cell activation syndrome

Consultation with an allergist or immunologist may help patients with severe symptoms.

Autoantibodies and autoimmunity

Treatment of the underlying disorder is recommended and can result in significantly improved POTS symptoms.

SPECIALTY CARE REFERRAL

POTS can be challenging to manage. Given the range of physiologic, emotional, and functional distress patients experience, it often requires significant physician time and multidisciplinary care. Patients with continued severe or debilitating symptoms may benefit from referral to a tertiary-care center with experience in autonomic nervous system disorders.

PROGNOSIS

Limited data are available on the long-term prognosis of POTS, and more studies are needed in pediatric and adult populations. No deaths have been reported in the handful of published cases of POTS in patients older than 50.1 Some pediatric studies suggest that some teenagers “outgrow” their POTS. However, these data are not robust, and an alternative explanation is that as they get older, they see adult physicians for their POTS symptoms and so are lost to study follow-up.6,44,69

We have not often seen POTS simply resolve without ongoing treatment. However, in our experience, most patients have improved symptoms and function with multimodal treatment (ie, exercise, salt, water, stockings, and some medications) and time.

Next Article:

Dabigatran-induced esophagitis

Related Articles