Midodrine helps reduce fainting
Midodrine, when administered in tandem with guidance on lifestyle risk reduction, lowered the recurrence of vasovagal syncope among patients who experienced fainting spells, data show.
“This is the first time that a medication has been shown in a randomized clinical trial to treat the commonest cause of fainting, which happens to perhaps 50% of people in their lives,” Robert S. Sheldon, PhD, MD, a professor of cardiac sciences at the University of Calgary in Canada, told Healio Primary Care. “Other properly done studies have hinted that other drugs might work, but nothing has been as clear cut as this study.”
Sheldon and colleagues randomly assigned 133 patients with recurrent vasovagal syncope in a 1:1 ratio to receive placebo or midodrine. The patients’ ages ranged from 25 to 47 years and 73% were women. All had a median of six syncope episodes in the previous year and none had any comorbidities.
The patients were also “taught the pathophysiology of vasovagal syncope; reassured about its benign nature; and provided advice on conservative measures to prevent vasovagal syncope, including physical maneuvers and dietary advice that emphasized fluid and sodium intake,” Sheldon and colleagues wrote in Annals of Internal Medicine. Most patients were followed until their first syncope episode or for 12 months.
Sheldon and colleagues reported that 42% of midodrine recipients had at least one syncope episode compared with 61% of placebo recipients (RR = 0.69; 95% CI, 0.49-0.97). The absolute risk reduction was 19 percentage points (95% CI, 2-36), and the number needed to treat to prevent one patient from having an episode was 5.3 (95% CI, 2.8-47.6). The time to first syncope was longer among midodrine recipients (HR = 0.59; 95% CI, 0.37-0.96). In addition, the type and occurrence of adverse events — including temporary tingling or prickling of body digits, erection of skin hair, headache and nausea — were similar among both groups, according to the researchers.
Sheldon said he was not surprised by the results.
“There were ample preliminary data that suggested that this would be a positive study,” he said.
Given the statistical significance of the findings, a larger trial would likely yield the same results, according to Sheldon.
Before prescribing pharmacological treatment to patients with recurrent vasovagal syndrome, Sheldon encouraged primary care physicians to try “conservative measures first,” including educating patients about the condition, reassuring patients the condition usually causes no harm, and, if the patient does not have heart failure or high BP, encouraging him or her to increase their salt and water intake.
Michele Brignole, MD, of the Istituto Auxologico Italiano, San Luca Hospital in Milan, Italy, wrote in a related editorial that in addition to midodrine, treatment options for recurrent vasovagal syncope include counterpressure maneuvers, fludrocortisone, cardiac pacing and deprescribing of antihypertensive medications.
“Other promising therapies” that are being evaluated for the condition include atomoxetine, theophylline and cardiac ganglia ablation, but “it seems no one therapy is effective in all patients,” she added.
“Now that we have identified several effective therapies, we need to learn how to best apply them to individual patients,” she wrote. “It is time to move toward personalized, mechanism-specific medicine.”
To do so, physicians should thoroughly assess the primary reason for the syncope and select a treatment based on the phenotype, she wrote.
“The identification of the precise mechanism of recurrent vasovagal syncope and personalized treatment should be the focus of future research in this field,” Brignole concluded.
References:
Brignole M. Ann Intern Med. 2021;doi:10.7326/M21-2859.
Sheldon RS, et al. Ann Intern Med. 2021;doi:10.7326/M20-5415.