Primidone | Health Dictionary

A barbiturate-related drug (see BARBITURATES) used to treat all forms of EPILEPSY, except in su?erers who do not have seizures.


Primidone | Health Dictionary

Keywords of this word: Primidone


Medical Dictionary

Drugs that reduce or prevent the severity of an epileptic convulsion or seizure (see EPILEPSY). The nature of the ?t, and the patient’s reaction to it, in?uences the type of anticonvulsant used. Anticonvulsants inhibit the high level of electrical activity in the brain that causes the ?t. Among regularly used anticonvulsants are carbamazepine, sodium valproate, clonazopam, lamotrigine, gabapentin, vigabatrin, and topiramate. Older drugs such as phenytoin and primidone remain useful in some patients. Intravenous anticonvulsants, such as diazepam, are used for rapid control of epileptic status.... Medical Dictionary

Medical Dictionary

(See also FIT; SEIZURE.) Epilepsy is the name given to any condition in which a person su?ers repeated ?ts or seizures. It is present in one in 200 (0·5 per cent) of the population and up to 5 per cent of all children will have had a ?t by the age of 12, although most of these are harmless accompaniments of an acute feverish illness.

It is a recurrent and paroxysmal disorder starting suddenly and ceasing spontaneously due to occasional sudden excessive rapid and local discharge of the nerve cells in the grey matter (cortex) of the BRAIN. Epilepsy always arises in this way from the brain, but its origin is often of microscopic size. It is diagnosed by the clinical symptoms based on the observations of witnesses. Its cause can sometimes be established by laboratory tests, and brain scanning. Fits can be the ?rst sign of a tumour, or follow a stroke, brain injury or infection, but in the large majority no underlying cause is found – so-called idiopathic epilepsy.

A single epileptic ?t is not epilepsy. Of those people who have a single seizure, a signi?cant minority (20 per cent) have no further attacks.

Major (generalised) seizures have a sudden, often unprovoked onset; the patient emits a cry, then falls to the ground, rigid, blue, and then twitching or jerking both sides of the body: the tonic-clonic convulsion. Drowsiness and confusion may last for some hours after recovering consciousness. Some experience a momentary warning (AURA): a smell, or sensation in the head or abdomen, vision, or déjà vu.

Partial seizures: focal motor (Jacksonian) begin with twitching of the angle of the mouth, the thumb, or the big toe. If the seizure discharge then spreads, the twitching or jerking spreads gradually through the limbs. Consciousness is preserved unless the seizure spreads to produce a secondary generalised ?t. In some attacks the eyes and head may turn, the arm may rise, and the body may turn, while some patients feel tingling in the limbs.

Complex partial seizures (temporal lobe epilepsy) The patient usually appears blank, vacant and may be unable to talk, or may mumble or chatter – though later they often have no memory of this period. They may be able to carry out complex tasks, taking o? gloves or clothes, and may smack their lips or rub repeatedly on one limb (automatisms). A sense of strangeness supervenes: unreality, or a feeling of having experienced it all before (déja vu). There may be a sense of panic. Strange unpleasant smells and tastes are olfactory and gustatory hallucinations. The visual hallucinations evoke complex scenes. An initial rising sense of warmth or discomfort in the stomach, or ‘speeding-up’ of thoughts are common psychomotor symptoms. All these strange symptoms are brief, disappearing within a few seconds or up to 3–4 minutes.

Minor seizures (petit mal) Attacks start in childhood. They last a few seconds. The child ceases what he or she is doing, stares, looks a little pale, and may ?utter the eyelids. The head may drop forwards. Attacks are commonly provoked by overbreathing. The child and parents may be unaware of the attacks

– ‘just daydreaming’. Major ?ts develop in one-third of subjects. By contrast with other types of epilepsy, the ELECTROENCEPHALOGRAM (EEG) is diagnostic.

Precautions Children with epilepsy should take normal school exercises and games, and can swim under supervision. Adults must avoid working at heights, with exposed dangerous machinery, and driving vehicles on public roads. Current legislation allows driving after two years of complete freedom from attacks during waking hours; those who for more than three years have had a history of attacks only while asleep may also drive.

Treatment identi?es, and avoids where possible, any factors (such as shortage of sleep or excessive ?uids) which aggravate or trigger attacks. If ?ts are very infrequent, treatment may not be recommended. However, frequent ?ts may be embarassing, may cause injury or may cause long-term brain damage so treatment is advisable. Anti-epileptic drugs are usually necessary for several years under medical supervision. Carbamazepine and sodium valproate are the most frequently prescribed. The dose is governed by the degree of control of ?ts and sometimes drug levels can be monitored by blood tests to check on dosage. Strict adherence to the drug schedule gives a reasonable chance of total suppression of ?ts, especially in younger patients whose ?ts have started recently. The table summarises anticonvulsant drugs in use. Interactions can occur between anti-epileptics and, if drug treatment is changed, the patient needs careful monitoring. In particular, abrupt withdrawal of a drug should be avoided as this may precipitate severe rebound seizures.

Indications First-choice drugs: Ethosuximide PM, JME Phenobarbitone M, P Phenytoin M, P, CP Carbamazepine M, P, CP Valproate M, PM, JME Second-line drugs: Primidone M, P, CP Clobazam M, CP Vigabatrin M, P, CP Lamotrigine M, P, CP Gabapentin M, P, CP Topirimate P

M = major generalised tonic-clonic; P = partial or focal; CP = complex partial (temporal lobe); PM = petit mal; JME = juvenile myoclonic epilepsy.

Anticonvulsant drugs

As all anticonvulsant drugs have an e?ect on the brain, it is not surprising that there may be side-e?ects, especially inolving alertness or behaviour. In each case careful assessment is necessary for doctor and patient to agree on the best compromise between stopping ?ts and avoiding ill-e?ects of medication.

Patients who have an epileptic seizure should not be restrained or have a gag or anything else placed in their mouths; nor should they be moved unless in danger of further injury. Any tight clothing around the neck should be loosened and, when the seizure has passed, the person should be placed in the recovery position to facilitate a return to consciousness (see APPENDIX 1: BASIC FIRST AID).

Patients with epilepsy and their relatives can obtain further advice and information from the British Epilepsy Association or Epilepsy Action Scotland.... Medical Dictionary