Paramedics can safely and effectively treat potentially life-threatening seizures using intravenous injections of mild tranquilizers, according to a new study in The New England Journal of Medicine.
Seizures were halted before they got to the emergency room in 59 percent of patients who received the drug lorazepam (also sold as Ativan) and in 43 percent of patients who got diazepam (Valium). Among patients given a placebo drug, only 21 percent reached the hospital without seizures.
The study, carried out by researchers at the University of California-San Francisco and published Thursday, included 205 patients diagnosed by city paramedics with "status epilepticus" - continuous or repeated seizures lasting five minutes or more without recovering consciousness.
About half the people in the study were suffering seizures due to epilepsy, the rest from other causes including alcohol abuse, adverse drug reactions, stroke or head trauma.
"A patient with this type of seizure needs to be treated as quickly as possible in order to prevent serious neurological damage," said Dr. Audrey Penn, acting director of the National Institute of Neurological Disorders and Stroke, which funded the research. "This study demonstrates that there is a safe and early treatment for a serious condition."
The likelihood of brain damage is reduced if seizures are stopped within 30 minutes, and some paramedic units around the country already administer the tranquilizers, part of a class of drugs known as benzodiazepines. Usually, they administer Valium because it's more stable and easily stored than others in the class.
But because the drugs suppress the central nervous system, they can cause some patients to stop breathing, breath too shallowly, or cause heart problems - complications that may be difficult to address in an ambulance. So, in many places, the drugs are administered to seizure victims only when they reach an emergency room, which often pushes or exceeds the 30-minute ideal treatment window.
Until now, there had been no systematic, controlled study to determine if the benefits of delivering the drugs earlier outweigh the potential serious side effects.
The San Francisco paramedics involved in the study had all received special training in diagnosing and treating seizures. They were in radio contact with a doctor who authorized enrollment in the study and they started the treatment using one of three color-coded kits stocked in their ambulance.
Researchers found complications with breathing or the cardiovascular system occurred in 11 percent of the patients who got lorazepam and in 10 percent injected with Valium. But the rate of problems was more than twice as high - 23 percent - in patients who were injected with a placebo solution.
"This study will reassure many EMS systems that treatment with benzodiazepines is both safe and effective," said Brian Alldredge, a professor of clinical pharmacy and neurology at the University of California-San Francisco and lead author of the study.
"It suggests too that lorazepam is likely to be a better choice than diazepam. Lorazepam is not as stable in warm climates, so in hot areas (where temperatures regularly exceed 85 degrees), it might be necessary to install refrigeration units on ambulances," he said. The drug kits in San Francisco were replaced every two months.
The researchers also noted that 40 percent to 57 percent of the patients treated with the drugs were still having seizures when they reached the emergency department and that those patients were twice as likely to require intensive care than patients whose seizures ended earlier.
Alldredge hopes to do more studies using higher doses of tranquilizers or administered through other delivery routes, such as intramuscular injection, which are easier to give aboard an ambulance than IV injections.
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