Treatment Of Epilepsy In The Elderly Patients

Mousumi Kar

Epilepsies are a group of disorders characterized by chronic, recurrent, paroxysmal
changes in the neurologic function caused by abnormalities in electrical activity
of the brain, estimated to affect 0.5-2% of the population and can occur at
any age⁵. Seizures are abnormal spontaneous discharges of the brain
neurons¹³, may affect part (focal) or all general of the brain. Overall
incidence is 70 per 100000 per year. Prevalence is 9 per 100 persons (0.9%).

Seizures occur in an age dependent, bimodal pattern. Although there is an initial peak in incidence during the first year of the life, there appears to be an epidemic of epilepsy after the age of 60 yrs¹². In fact, the incidence of epilepsy is higher in patients older than 75 yrs of age than in the children, younger than the age of 10 yrs. Seizures are very common in the elderly, which is generally seen to be associated with degeneration of the brain⁴.

 Seizures may occur following cerebral infarction, particularly if the lesion is hemorrhagic. Intra-cerebral hemotoma with involvement of the cortex is complicated by both acute and recurrent generalized seizures in 9 to 10 % of patients. Brain tumors have a higher incidence in the elderly. Metabolic disorders, including renal and hepatic failures, are also a commonly complicated by seizures. Anoxic brain injury may be followed by mycolic, focal, or recurrent generalized seizures; alcohol withdrawal seizures have their peak incidence in late adulthood. Partial seizures tend to be more common in the elderly, whereas generalized tonic-clonic seizures have a relatively constant incidence over all age groups. This pattern is best attributed to the cause specific etiology of cortical injury. With elderly patients, management decisions are based on accurate classification of seizures or epilepsy syndromes, through neurological assessment to define etiology, and comprehensive assessment of the patient’s health and living situations. General health of the patient and all the medications used by the patient influence the selection and use of an anti epileptic drug.

There are several drugs available for the management of the psychotic disorders, but noncompliance level is as high as 15-55%, which may be due to cost of the drugs, personal problems and social factors. Seizures are of many types based on the area affected and the symptoms associated. The general classification of seizure include the following

International classification of epileptic seizures

1.   Partial seizures

a.   Simple partial seizures (no impaired consciousness)

b.   Complex partial seizures (impaired consciousness)

c.   Partial seizures evolving into secondary generalized seizures

2.   Generalized seizures

3.   Absence seizures

4.   Myoclonic seizures

5.   Clonic seizures

6.   Tonic seizures

7.   Tonic-clonic seizures

8.   Atonic seizures

9.  Unclassified seizures

Causes of seizures in elderly

Most of the cases are idiopathic and also post traumatic, cerebro-vascular disease, post or peri stroke, recurrent chronic ischemia, seizures most common with large hemorrhagic areas of infarction, tumor - 10 % of new onset seizures, recreational drugs, alcohol withdrawal seizures (more common than during use) and also the use of hallucinogenic agents as cocaine. The other reasons include metabolic, hypoglycemic, hypo-natremia, hypo- calcemia, hyper-natremia, and induced calcium and magnesium levels which have been found to increase the risk of seizures and also uremia, cirrhosis / liver failure, infection, meningitis - usually bacterial, encephalitis - usually viral, brain abscess, parasitic.

Medications

The rational management of epilepsy needs an accurate diagnostic evaluation of the epileptic syndrome and if possible, of the specific underlying cause. Currently, there is no ‘drug cure’ for epilepsy¹⁰. There are various drugs available for controlling epilepsy and seizures, but the use of specific medication is directed when it is to be used for the elderly patients as they have a diminishing metabolism rate. The treatment in elderly patients is a challenge due to high non compliance rate, declining memory, intellect and the fast rate of decline in the metabolism. However, when a drug is selected for the treatment the care need be taken for the complete pharmaco-kinetic profile of the drug and body function of the patient. Most drugs used are the anti-psychotics which include pentobarbitals, benzodiazepines, and the newly approved agents as felbamate, gabapentin, lamotrigine, tiagabine, topiramate, oxcarbazepine, vigatribine and zonisamide. Table 1

Pentobarbitals:

Pentobarbital is not highly protein bound. Little specific information is available regarding the clearance in the elderly. There is some evidence that clearance is reduced in the elderly. This change suggests the practical actions of using lower total maintenance doses and expecting an increase in the time to reach steady state when initiating therapy.

Benzodiazepines:

Benzodiazepines are used commonly in the elderly for the treatment of behavioral changes. These drugs are highly protein bound; the metabolite of Diazepam, Desmethyl Diazepam, is pharmacologically active as well. Whereas the free fraction of diazepam increases with age, the clearance of the unbound drug decreases, prolonging the plasma half life of the drug and the metabolite is 90% protein bound¹⁴. Therefore, the free fraction of the drug and the volume of distribution increase with age. These patients are sensitive to effects on neural function that are independent of elimination half life, volume of distribution, and protein binding.

Newly approved drugs:

Newly approved anti-epileptic drugs are not yet tested in elderly patients for the reasons concerning the approval, and the consent from the elderly. Another reason being the drug development protocols which usually prohibit elderly patients for the study. The drugs that are generally used include¹¹ oxcarbazepine, felbamate, gabapentin, lamotrigine, topiramate and tiagabine.

The drugs that are to be used in the treatment of epilepsy and related conditions must be very nicely studied, in order to determine the adverse effects, which may be precipitated due to the rapidly deteriorating body mechanisms in them. The decision to decide which drug is safer to use in elderly totally thus is to be decided by the physician and the pharmacist. Thus, a pharmacist can play a major role in the medication for the elderly.

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Table 1. List of Drugs with Uses, Adverse Effects and Pharmacokinetics

About Authors:

Mousumi K. * and Reddy M. S¹

*Department of Pharmaceutical Sciences, MLSU, Udaipur ,  
¹College of Pharmaceutical Sciences, Manipal                 

Mrs. Mousumi Kar
Asst. Proff.
Department of Pharmaceutical Sciences
Mohan Lal Sukhadia University
Email: karmousumi@hotmail.com

> Present status: Pursuing PhD and working as lecturer
in Mohan Lal Sukhadia University, Udaipur.
> Completed M Pharm. in Pharmaceutics from College of Pharmaceutical
Sciences, (COPS), Manipal, Karnataka state on the topic ‘Floating drug
delivery system for an antipsychotic agent’.
> Got research papers published in various national and
international journals.