Methyldopa for hyperadrenergic postural orthostatic tachycardia syndrome: A case series of five patients

To describe the therapeutic capability of methyldopa in patients with postural orthostatic tachycardia syndrome (POTS) and clinical features suggestive of a hyperadrenergic subtype. We conducted a retrospective chart review of five patients diagnosed with POTS at the Calgary Autonomic Investigation and Management Clinic that had hyperadrenergic features, such as episodes of tremors, diaphoresis, heat intolerance, irritability and/or increased anxiety, and were treated with methyldopa. Demographics, clinical features, autonomic function testing results, and treatment response were collected. Autonomic testing included head-up tilt table testing or active stand testing, and the Valsalva maneuver. Patients also completed an online survey assessing response to methyldopa via the Malmö POTS symptom score (MaPS). All five patients in this case series had POTS with hyperadrenergic features including episodes of tremors, diaphoresis, heat intolerance, irritability and/or increased anxiety often occurring at night. All five patients reported improvements in their orthostatic symptoms and sleep quality while taking methyldopa, with fewer episodes of nocturnal tachycardia, diaphoresis, and/or tremors. Overall, fatigue was improved in these patients. All patients lacked orthostatic hypertension on at least one visit, only one patient had orthostatic hypertension on formal active stand/head up tilt-table testing, and only two of the four patients had ∆DBP > 17 mmHg or a vigorous Phase 2 L SBP recovery on Valsalva (putative markers of a hyperadrenergic state in POTS). In patients with POTS and hyperadrenergic features, methyldopa is a safe central acting sympatholytic that can be used to treat their hyperadrenergic symptoms.