140 Midodrine Hydrochloride in the Management of Elderly Patients with Neurocardiogenic Syncope: A Prospective Observational Study

Background Midodrine hydrochloride is an alpha-1 agonist that has been used in the management of syncope in patients with orthostatic hypotension, vasovagal syncope and vasodepressor carotid sinus syndrome when non-pharmacological means have failed. However, there are very limited information about its use, tolerability and side effects among the elderly population. Objectives We aim to document effectiveness of Midodrine in patients who have been diagnosed with neurocardiogenic syncope assessed and managed at a specialist falls and syncope outpatient unit. We monitored for changes in patients' symptoms, adverse reactions reported and optimum drug dosages that have shown benefit in this cohort of patients. Methods A prospective observational study of 33 subjects aged between 68 and 94 (mean age 79) who have been started on Midodrine therapy following positive tilt table test or confirmed diagnosis of symptomatic orthostatic hypotension despite conservative managements. They have been followed up for a mean of 2.9 years. Results 81% of patients( n=27) reported significant improvement in their symptoms. Although 7 patients reported adverse reactions to Midodrine, the majority of the patients tolerated the therapy well and continued on the treatment except for one patient who experienced gastrointestinal discomfort and withdrew completely. Commonest side effects are pruritus and piloerection, but they are not amenable to treatment due to underlying mechanism of action of Midodrine on hair follicles. The dosage varies from 2.5mg to 10mg, taken at 8am, 12pm and 5pm due to risk of nocturnal supine hypertension. Higher dose did not correlate with higher possibility of experiencing side effects. Conclusion Midodrine appears to be effective, safe and well tolerated among the elderly population. It should be considered in the management of patients with neurocardiogenic syncope when non-pharmacological means have failed, irrespective of age. This observational study requires further confirmation by randomised control studies with larger sample size.