354
P A R T 4
Drugs acting on the central and peripheral nervous systems
BOX 23.2
Drug therapy across the lifespan
Antiseizure agents
CHILDREN
Antiepileptic drugs can have an impact on a child’s
learning and social development. Children may also be
more sensitive to the sedating effects of some of these
drugs. Children should be monitored very closely and
often require a switch to a different agent or dosage
adjustments based on their response.
Newborns (1 to 10 days of age) respond best to
intramuscular phenobarbitone if an antiepileptic is needed.
Older children (2 months to 6 years of age) absorb and
metabolise many of these drugs more quickly than adults
do and require a larger dosage per kilogram to maintain
therapeutic levels. Careful calculation of drug dosage
using both weight and age are important in helping the
child to receive the best therapeutic effect with the least
toxicity. After the age of 10 to 14 years, many of these
drugs can be given in the standard adult dose.
Parents of children receiving these drugs should
receive consistent support and education about the seizure
disorder and the medications being used to treat it. Many
communities have local support groups that can offer lots
of educational materials and support programs. It is a very
frightening experience to watch your child have a tonic–
clonic seizure and parents should be supported with this
in mind.
ADULTS
Adults using these drugs should be under regular care
and should be monitored routinely for adverse effects.
They should be encouraged to carry or wear a Medic-
Alert identification to alert emergency personnel that
antiepileptic drugs are being taken. Adults also need
education and support to deal with the old stigma of
seizures as well as the lifestyle changes and drug effects
that they may need to cope with.
PREGNANCY AND BREASTFEEDING
Most of these drugs have been associated with fetal
abnormalities in animal studies. Some of them are clearly
associated with predictable congenital effects in humans.
Women of childbearing age should be encouraged
to use contraceptives while taking these drugs. If a
pregnancy does occur, or if a woman taking one of these
drugs desires to become pregnant, the importance of
the drug to the mother should be weighed against the
potential risk to the fetus. Stopping an antiepileptic can
precipitate seizures that could cause anoxia and its related
problems for the mother and the baby. Women who are
breastfeeding should be encouraged to find another way
of feeding the baby to avoid the sedating and central
nervous system (CNS) effects that the drugs can have on
the infant.
OLDER ADULTS
Older people may be more susceptible to the adverse
effects of these drugs. Dosages of all of these drugs may
need to be reduced, and the person should be monitored
very closely for toxic effects and to provide safety
measures if CNS effects do occur.
People with renal or hepatic impairment should be
monitored very closely. Baseline renal and liver function
tests should be done and dosages adjusted as appropriate.
Serum levels of the drug should be monitored closely in
such cases to prevent serious adverse effects.
The older person should also be encouraged to
wear or carry Medic-Alert identification in case there is
an emergency and they are not able to communicate
information about the drug or disorder.
Altered metabolism of antiseizure agents
Because of differences in liver enzyme functioning
among Arabs and Asians, people in these ethnic groups
may not metabolise antiseizure agents in the same way
as people in other ethnic groups.They may require not
only lower doses to achieve the same therapeutic effects,
but also frequent dose adjustment.
Nurses and midwives need to be aware that the
therapeutic range for people in these ethnic groups
may differ from standard norms and that these people
may be more apt to show adverse or toxic reactions
to antiepileptic drugs at lower doses. As with all
medications, the lowest possible dose should be used.
Serum drug levels should be closely monitored and
titrated carefully and slowly to achieve the maximum
benefits with the fewest adverse effects.
Cultural considerations
BOX 23.3
■■
TABLE 23.1 Antiepileptic drug therapy grouped
by seizure class
Seizures
Generalised seizures
(except status
epilepticus)
Status epilepticus
Carbamazepine Carbamazepine
Diazepam
Clonazepam Clonazepam Lorazepam
Gabapentin
Ethosuximide
Midazolam
Lacosamide
Lamotrigine
Phenobarbitone
Lamotrigine
Levetiracetam Phenytoin
Levetiracetam Oxcarbazepine
Propofol
Oxcarbazepine
Phenytoin
Phenytoin
Sodium valproate
Pregabalin
Topiramate
Sodium valproate Vigabatrin
Tiagabine
Zonisamide
Topiramate
Zonisamide
Adpted from Aschenbrenner, D. S. &Venable, S. J. (2008). DrugTherapy
in Nursing (3rd edn). Philadelphia: Lippincott Williams &Wilkins, p. 331.
