Characterization of the changes in supine blood pressure with long-term use of droxidopa in patients with neurogenic orthostatic hypotension

BACKGROUND AND AIMS

Patients with neurogenic orthostatic hypotension (nOH) due to autonomic dysfunction may also experience supine hypertension (defined as supine systolic blood pressure [SBP] ≥140 mmHg). Because pressor agents used to improve nOH symptoms by increasing standing blood pressure (BP) may exacerbate or cause supine hypertension, changes in supine BP with nOH treatments are of interest.

METHODS

This post hoc study examined changes in SBP in patients receiving droxidopa (100-600 mg, three times daily) during a 12-month long-term extension study based on whether patients had supine hypertension (ie, supine SBP ≥140 mmHg) at baseline. Shifts from baseline in supine hypertension categorization and mean supine and standing SBP after 6 and 12 months of treatment with droxidopa were determined.

RESULTS

At baseline, 64 patients did not have supine hypertension (mean supine SBP, 120 mmHg) and 38 patients had supine hypertension (mean supine SBP, 157 mmHg). A similar percentage of patients shifted from their respective baseline supine hypertension categorization (ie, with or without supine hypertension) to the other category after receiving droxidopa for 6 or 12 months. After 12 months of droxidopa treatment, patients with supine hypertension at baseline had a mean supine SBP decrease of 3 mmHg and a mean standing SBP increase of 9 mmHg. Patients without supine hypertension at baseline had mean supine and standing SBP increases of 12 and 15 mmHg, respectively.

CONCLUSIONS

There was no consistent or progressive elevation in supine SBP over time during the 12-month treatment with droxidopa in patients either with or without supine hypertension at baseline. These data suggest that long-term droxidopa treatment for nOH does not adversely affect supine BP.

Diagnosing and treating neurogenic orthostatic hypotension in primary care

In response to a change in posture from supine or sitting to standing, autonomic reflexes normally maintain blood pressure (BP) by selective increases in arteriovenous resistance and by increased cardiac output, ensuring continued perfusion of the central nervous system. In neurogenic orthostatic hypotension (NOH), inadequate vasoconstriction and cardiac output cause BP to drop excessively, resulting in inadequate perfusion, with predictable symptoms such as dizziness, lightheadedness and falls. The condition may represent a central failure of baroreceptor signals to modulate cardiovascular function, a peripheral failure of norepinephrine release from cardiovascular sympathetic nerve endings, or both. Symptomatic patients may benefit from both non-pharmacologic and pharmacologic interventions. Among the latter, two pressor agents have been approved by the US Food and Drug Administration: the sympathomimetic prodrug midodrine, approved in 1996 for symptomatic orthostatic hypotension, and the norepinephrine prodrug droxidopa, approved in 2014, which is indicated for the treatment of symptomatic neurogenic orthostatic hypotension caused by primary autonomic failure (Parkinson's disease, multiple system atrophy and pure autonomic failure). A wide variety of off-label options also have been described (e.g. the synthetic mineralocorticoid fludrocortisone). Because pressor agents may promote supine hypertension, NOH management requires monitoring of supine BP and also lifestyle measures to minimize supine BP increases (e.g. head-of-bed elevation). However, NOH has been associated with cognitive impairment and increases a patient's risk of syncope and falls, with the potential for serious consequences. Hence, concerns about supine hypertension - for which the long-term prognosis in patients with NOH is yet to be established - must sometimes be balanced by the need to address a patient's immediate risks.