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Effect of midodrine on orthostatic intolerance after hip and knee arthroplasty: A randomized controlled trial (the
Monica Skarin1, Jill Collier1, David Rice2
1Department of Anesthesiology and Perioperative Medicine, Health New Zealand Waitematā, Private Bag 93503, Takapuna, Auckland 0740, New Zealand.
Background:
Orthostatic intolerance (OI), characterized by dizziness and nausea during postural change, is common after hip and knee arthroplasty and can delay mobilization and discharge. Midodrine, an oral alpha-1 agonist, may reduce OI by improving vascular tone, but evidence in this setting is limited.
Methods:
A double-blind, randomized, placebo-controlled trial was performed in adults undergoing primary unilateral total hip or knee arthroplasty. Patients received oral midodrine hydrochloride 10 mg or placebo (four to five doses over 24-30 h). Mobilization included a standardized orthostatic challenge on postoperative days 0 and 1 with continuous beat-to-beat blood pressure monitoring. The primary outcome was OI during first mobilization on day 0. Secondary outcomes included OI on day 1, orthostatic hypotension, safety, hemodynamic responses, and length of stay.
Results:
170 patients were randomized; 159 were included in the modified intention-to-treat analysis. On day 0, OI occurred in 18% of patients receiving midodrine versus 33% receiving placebo (adjusted relative risk 0.56; p = 0.038). On day 1, OI occurred in 6% versus 15%, respectively (unadjusted relative risk 0.41; p = 0.064). Syncope occurred only in the placebo group (8%). Midodrine increased supine systolic and diastolic blood pressure at first mobilization and reduced symptom-defined OI, while the incidence of orthostatic hypotension defined by blood pressure thresholds did not differ between groups. Median length of stay was 2 days with midodrine versus 3 days with placebo. Adverse events were similar.
Conclusion:
Regular postoperative administration of midodrine 10 mg is well tolerated and reduces clinically relevant OI during early mobilization following hip and knee arthroplasty, potentially supporting safer and earlier recovery.