Standard Valsalva is safe, but achieves cardioversion for only 5% to 20% of patients with acute SVT. Nonresponders usually receive intravenous adenosine, which causes transient asystole and has other side effects, including a sense of “impending doom” or imminent death, the investigators noted.1
For the modified Valsalva maneuver, patients underwent standardized strain at 40 mm Hg pressure for 15 seconds while semi-recumbent, but then immediately laid flat while a staff member raised their legs to a 45-degree angle for 15 seconds. They returned to the semi-recumbent position for another 45 seconds before their cardiac rhythm was reassessed. The control group simply remained semirecumbent for 60 seconds after 15 seconds of Valsalva strain.
The adapted technique should achieve the same rate of cardioversion in community practice, and clinicians should repeat it once if it is not initially effective, said the researchers. “As long as individuals can safely undertake a Valsalva strain and be repositioned as described, this maneuver can be used as the routine initial treatment for episodes of supraventricular tachycardia regardless of location,” they said. Patients did not experience serious adverse effects, and transient cardiac events were self-limited and affected similar proportions of both groups, they added.
The National Institute for Health Research funded the study. The researchers declared no competing interests.
Off-label prescriptions link to more adverse events
BY MARY ANN MOON
FROM JAMA INTERNAL MEDICINE
Vitals Key clinical point: Off-label prescribing in adults is common and very likely to cause adverse events. Major finding: The incidence of adverse events was 44% higher for off-label use (19.7 per 10,000 person-months) than for on-label use (12.5 per 10,000 person-months) of prescription drugs. Data source: A prospective cohort study of 46,021 adults who received 151,305 incident prescriptions from primary care clinicians in Quebec during a 5-year period. Disclosures: No sponsors were identified for this study. Dr Tewodros Eguale and his associates reported having no relevant financial disclosures. |
Off-label prescribing of drugs is common and very likely to cause adverse events, particularly when no strong scientific evidence supports the off-label use, according to a report published in JAMA Internal Medicine.
No systematic investigation of the off-label use of prescription drugs has been done to date, in part because physicians aren’t required to document intended indications. Recent innovations in electronic health records provided an opportunity to track off-label prescribing and its influence on adverse drug events for all 8.5 million residents in the Canadian province of Quebec. There, physicians must provide the indication for every new prescription, the reason for any dose changes or drug discontinuation, and the nature of any adverse events, said Dr Tewodros Eguale of the department of epidemiology, biostatistics, and occupational health at McGill University, Montreal, and his associates.
“Selected examples of adverse events associated with the most frequently used off-label drugs include akathisia resulting from the use of gabapentin for neurogenic pain; agitation associated with the use of amitriptyline hydrochloride for migraine; hallucinations with the use of trazodone hydrochloride for insomnia; QT interval prolongation with the use of quetiapine fumarate for depression; and weight gain with the use of olanzapine for depression,” the authors reported.
Prescribing information in electronic medical records of 46,021 adults (mean age 58 years) given 151,305 new prescriptions was analyzed during a 5-year period. Physicians reported off-label use in 17,847 (12%) of these prescriptions, and that off-label use lacked strong scientific evidence in 81% of cases. The median follow-up time for use of prescribed medications was 386 days (range, 1 day to 6 years).
The class of drugs with the highest rate of adverse effects was anti-infective agents (66.2 per 10,000 person-months), followed by central nervous system drugs such as antidepressants, anxiolytics, and antimigraine medicine (18.1 per 10,000); cardiovascular drugs (15.9 per 10,000); hormonal agents (12.7); autonomic drugs including albuterol and terbutaline (8.4); gastrointestinal drugs (6.1); ear, nose, and throat medications (2.8); and “other” agents such as antihistamines, blood thinners, and antineoplastics (1.3).
“Off-label use may be clinically appropriate given the complexity of the patient’s condition, the lack of alternative effective drugs, or after exhausting approved drugs.” However, previous research has shown that physicians’ lack of knowledge of approved treatment indications was one important factor contributing to off-label prescribing. And one study showed that physicians are finding it difficult to keep up with rapidly changing medication information, and this lack of knowledge is affecting treatment, Dr Eguale and his associates said.