Rescue Medications for Home Treatment of Acute Seizures
Epilepsy is a chronic disease and is treated with continuous medications aiming at sustained complete seizure control. However, in its course, emergency situations may sometimes arise that require acute interventions. In some epileptic conditions, seizures occur only occasionally but in series or prolonged states. These require rapid action, whereas continuous treatment may not be indicated. Rescue medication (RM) can also be used to prevent seizures when risk is perceived.
Conditions requiring acute drug administration
Febrile and nonfebrile serial seizures of childhood
Febrile seizures (FS) are the most frequent type of acute epileptic seizures and occur at the ages of 6 months to 5 years. There is a strong genetic predisposition. Although simple, uncomplicated FS have no sequelae, febrile status epilepticus has been correlated with the development of hippocampal sclerosis with the consequence of chronic temporal lobe epilepsy. It is therefore highly important that FS be treated as early and effectively as possible to prevent prolonged seizures. FS are often a once-in-a-lifetime event and not considered an indication for continuous antiepileptic drug (AED) treatment. However, recurrence occurs in up to one-third of children.
Recurrent prolonged and serial seizures unconnected with febrile illness are much more common in children than in adults and, in some patients, have a high risk of status epilepticus. RM should be made available.
Epilepsies with habitual clusters of seizures
In some patients with epilepsy, seizures habitually occur in clusters of several seizures on one or subsequent days. These clusters may affect ability to work, independence, and life quality much more than single seizures. In many cases, clusters can be effectively prevented by self-application of an RM after the first seizure.
Prodromes and auras
Some patients have “warnings” before their seizures. These can be auras—that is, subjective symptoms that seem to precede the seizure but actually are the first seizure symptoms. These are quite common but usually last only seconds or fractions of seconds, too short for any drug intervention. In some patients, however, the auras last on the order of minutes, and a rapidly acting drug can possibly interrupt these.
A more rare kind of warning is the prodrome, which precedes a seizure for periods from 30 min upwards. Sometimes prodromes represent increased subclinical seizure activity or very mild forms of nonconvulsive status epilepticus, and sometimes their background cannot be clarified. They may be registered by the patients themselves or observed as behavioral changes by others. They are an indication for RM only if they stand out clearly from the habitual interictal state. In these cases, an oral benzodiazepine (BZD) can prevent an imminent seizure.
Stress convulsions, provoked and lifestyle seizures, and social indications
Sleep disturbances increase the risk of seizures in many patients, especially when combined with excessive alcohol intake. Some patients with infrequent seizures even have exclusively provoked seizures that may also result from excessive psychophysical stress. They may be aware of the relationship but not necessarily willing to change their lifestyles. Prophylactic intake of an oral BZD at perceived risk can protect them against seizures. Prophylactic BZDs may also be recommended in cases of predictable sleep disturbances caused by overnight or transcontinental travel. People who travel a lot or have experienced a provoked seizure should have a small supply of a suitable BZD available.
Likewise, seizures can be prevented in socially important or potentially stigmatizing situations such as church services, the theater, concerts, and sports events, or when the patient is in the spotlight, as when performing at cultural, political, or scientific events, applying for a job, or presenting a project to a committee.
Reflex epileptic seizures (e.g., hot water epilepsy)
Reflex epilepsies are conditions where epileptic seizures habitually are precipitated by qualitatively, often even quantitatively, well-defined sensory or cognitive stimuli. Most patients also have spontaneous seizures that require continuous AED treatment. Others have only provoked seizures, or treatment controls the spontaneous but not the reflex seizures. If the seizure trigger cannot be avoided or attenuated (such as by the use of dark glasses to avoid photosensitive seizures), RM can be applied before the patient is exposed to the trigger. The best-known example is hot water epilepsy, a condition particularly common in South India, in which complex partial seizures habitually are provoked by pouring hot water over the head. In most cases, the application of 5–10 mg clobazam (CLB) 60–90 min before taking the head bath fully controls the seizures even without continuous AED treatment.
Drugs for acute anticonvulsive intervention
Whereas BZDs are rarely used for sustained epilepsy treatment because of frequent development of secondary tolerance, they are clearly the first-line rescue medicines due to their rapid action and high anticonvulsant effect. The principal adverse effects are sedation and respiratory suppression, but these effects have not been reported to cause serious problems in studies of home RM. BZDs are differentiated from each other mainly by their pharmacokinetic properties.