The drug midodrine can help patients with pulmonary arterial hypertension (PAH) tolerate the gradual increase in dosage of prescribed therapies without experiencing undesirable side effects, according to a study presented at the American Thoracic Society (ATS) 2022 Annual Meeting, held in San Francisco, CA, May 13 to 18.

Midodrine is used to treat orthostatic hypotension, which commonly occurs in patients taking PAH drugs. However, no study has investigated whether midodrine can relieve hypotension in such patients. Investigators for the current study sought to determine whether midodrine could stabilize the blood pressure of PAH patients, enabling them to continue their PAH medications.

Researchers based in Houston conducted a search of the Pulmonary Hypertension Center database at Houston Methodist Lung Center and found 132 individuals with idiopathic, inherited, or drug- or toxin-induced PAH who had been prescribed midodrine. Data on the midodrine titration and PAH therapies of the patients were extracted.


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A total of 7 PAH patients had hypotension severe enough to affect their therapy regimen. All had idiopathic PAH except 1 patient whose condition was induced by a drug or toxin. According to study researchers, patient data showed that the average time since diagnosis was 5 ± 5 years (mean ± SD), and the average pulmonary vascular resistance (PVR) at diagnosis was 13 ± 4 Wood units. All 7 patients were women, and their mean age was 38 ± 14 years.

The investigators’ review found that patients’ dosage of midodrine ranged from 2.5 mg 3 times a day (TID) to 10 mg TID. After getting the maximum tolerated dosage of midodrine, 6 of the 7 patients experienced higher mean arterial pressure, with an average change from baseline of 14 ± 16 mmHg. Mean arterial pressure before midodrine administration was 67 ± 9 mmHg and rose to 80 ± 11 mmHg (P =.027) after patients received the maximum dose.

In 6 patients, the doses of PAH therapy were increased or switched, or a medication was added. The remaining patient’s condition improved such that she no longer needed PAH therapy or midodrine.

“With the support of midodrine, patients are able to tolerate the uptitration and augmentation of PAH therapies,” the authors explained. “This combination can aid patients in reaching target PAH therapies to improve their symptoms and counteract their peripheral vasodilatory effects,” they noted.

Reference

Rao NI, Tanabe C, Sahay S, Safdar Z. Midodrine as a novel tool to optimize pulmonary arterial hypertension therapies. Presented at: the American Thoracic Society (ATS) 2022 International Conference; May 13-18, 2022; San Francisco, CA. Abstract P184.