Potentially life threatening seizures can be safely treated by paramedics using injections of diazepam or similar benzodiazepine drugs en route to the hospital, rather than waiting for hospital staff to administer the drugs, according to a new study led by researchers at the University of California, San Francisco .
The likelihood of brain damage is reduced if seizures are stopped quickly, and many paramedic units already administer benzodiazepines, bolstered by anecdotal evidence that they are effective in stopping seizures before reaching the hospital, the researchers note. But benzodiazepines can cause some people to stop breathing, breathe too shallowly or can cause cardiac complications, and emergency medical vehicles lack the full range of support measures available in hospitals to respond to these events.
The new study is the first to systematically examine the benefits of early administration of modest doses of benzodiazepines by paramedics and determine if the benefits clearly outweigh potential serious side effects.
Published in the New England Journal of Medicine , the study is based on 205 patients diagnosed with “status epilepticus” - a prolonged seizure or one seizure after another without regaining consciousness. About half the people in the study had seizures as a result of epilepsy, and about half experienced seizures from other causes, such as alcohol abuse, adverse drug reactions, stroke or head trauma.
Those who received the anti-seizure drugs in the ambulance were far more likely to be free of seizures by the time they reached the hospital than were those who remained unmedicated en route, the researchers found.
Although diazepam is currently the drug of choice used by paramedics to treat someone with a prolonged seizure, lorazepam, a related drug also in the benzodiazepine class, was found to be at least as effective and possibly more so, the study found. While 43 per cent of those given five-to-ten-milligram diazepam injections were seizure-free upon arrival at the hospital, almost 60 per cent of those given comparable doses of lorazepam were free of their seizures. The differences between the two drugs, while striking, were not found to be statistically significant because of the relatively small number of people in the study. By contrast with the two drug-treated groups, only 21 per cent of the unmedicated group were seizure free by the time they reached the hospital.
“This study will reassure many EMS [emergency medical services] systems that treatment with benzodizepines is both safe and effective” the researchers said. “It suggests too that lorazepam is likely to be a better choice than diazepam. Lorazepam is not as stable as diazepam in warm climates, so in hot areas, it might be necessary to install refrigeration units on ambulances.”