Reflex syncope is the most common cause of transient loss of consciousness. Practical manoeuvres may help, but additional measures are often required. In our experience, midodrine gives consistently good results in patients with reflex syncope. This study also provides reassurance that the effect on blood pressure is measureable, but small, and side effects are infrequent. UK prescribing may have been limited when midodrine was unlicensed, but midodrine is now licensed.
We treated 195 patients, age 40 ± 18 years, 72 (37%) aged under 30 years, 151 female (78%), who attended a Rapid Access Blackouts Triage Clinic and gave a clear history of reflex syncope. The median duration of symptoms was 28 months. A misdiagnosis of epilepsy had occurred in 39 patients and 42 had significantly low blood pressure.
Follow-up was 50 ± 42 months in 184 patients (93%), with 11 patients lost to follow-up. Twenty-eight patients had minor electrocardiogram (ECG) changes but had a normal echocardiogram. Overall, 143 (73%) patients improved on a mean dose of 10 mg a day of midodrine. Syncopal events fell from 16 ± 16 to 2.6 ± 5 per six months (p<0.05), and in 69 (35%) patients, syncope was eradicated. Nineteen (10%) patients were able to stop midodrine after 52 ± 42 months due to symptom resolution. Fifteen patients (7%) stopped midodrine because of side effects, while 17 (8%) patients failed to respond. Mean supine systolic blood pressure rose from 114 mmHg to 121 mmHg at final midodrine dose (p<0.05).
In conclusion, in patients with reflex syncope, midodrine shows clinical benefit in greater than 70%, with 24% having complete symptom resolution. Side effects are rare, and there is little evidence of a hypertensive effect.