Case report: severe myoclonus associated with oral midodrine treatment for hypotension

RATIONALE: Midodrine is widely used in the treatment of hypotensive states, there have been no reports of myoclonus associated with midodrine use in hypotension with chronic kidney disease. PATIENT CONCERNS: We report a 58-year-old female patient with chronic kidney disease (CKD) presenting with involuntary tremor 2 h after taking midodrine, which became more frequent after 6 h. Brain CT and neurological examination did not yield findings of note. Blood chemistry showed serum albumin of 3.1 g/L, ALT of 19 U/L, AST of 22 U/L, SCr of 273.9 μmol/L, K(+) of 2.94 mmol/L, Ca(2+) of 1.63 mmol/L, and Mg(2+) of 0.46 mmol/L. Her BP was maintained at 83–110/56–75 mmHg. Her urine volume was 600–1000 mL/d, and her heart rate was within a range of 90–100 beats/min. DIAGNOSIS: Chronic kidney disease (CKD), hypotension, metabolic acidosis, hypocalcemia, hypokalemia, and hypomagnesemia. INTERVENTIONS: Midodrine treatment was stopped and the patient was treated with intravascular rehydration and furosemide. Myoclonus ceased one day after midodrine withdrawal. LESSONS: Oral midodrine is widely used in the treatment of orthostatic hypotension, recurrent reflex syncope and dialysis-associated hypotension and the adverse effects are mostly mild. However, clinicians should be alert for midodrine-induced myoclonus, especially in patients with CKD.