The purpose of this review was to examine whether the routine use of antiepileptic medication in preventing epileptic seizures following subarachnoid haemorrhage can be justified. This includes patients who have not yet had a seizure (primary prevention) and those who have already had one (secondary prevention).

Epileptic seizures are caused by abnormal, rhythmic discharges of nerve cells within the brain leading to involuntary changes in body movement or function, sensation, awareness, or behaviour. Following a subarachnoid haemorrhage seizures can occur in up to 25% of patients, triggered by nerve cell damage caused by the blood itself, the formation of scar tissue, and swelling around the site of bleeding. Recurrent uncontrolled seizures can cause considerable morbidity and mortality, preventing neurological recovery and reducing quality of life. Conversely, side effects of antiepileptic medication include diarrhoea, nausea and vomiting, drowsiness, dizziness, agitation, tremor, confusion and skin rash. These need to be considered when prescribing antiepileptic medication, as the medication itself may hinder neurological recovery and rehabilitation.

To date there have been no randomised controlled trials comparing antiepileptic drugs with placebo following subarachnoid haemorrhage. Some retrospective studies have suggested worse outcomes in patients on higher doses and a longer duration of antiepileptic treatment, as explained in the review, but they do not provide the strength of evidence required for their use as a routine recommendation.

Currently, there is insufficient evidence to justify the routine use of antiepileptic medication for the primary and secondary prevention of seizures after subarachnoid haemorrhage, and a double blind randomised controlled trial comparing antiepileptic medication with placebo would help to clarify this important question.