Neurology & Mental Health

what happens when monotherapy with a first line antiepileptic drug is unsuccessful?

monotherapy with an alternative drug should be tried

• diagnosis should be checked before starting an alternative drug

• change from one antiepileptic to another should be cautious → slowly withdraw first drug only when new regimen has been established

what is the general opinion on adjunctive therapy with 2 or more antiepileptic drugs?

may be necessary if monotherapy is unsuccessful but the use of multiple antiepileptic drugs increases risk of adverse effects and drug interactions → if combination therapy does not reduce seizures then revert to the regimen that provided the best balance between tolerability and efficacy (can be monotherapy or combination therapy)

• single antiepileptic drug should be prescribed wherever possible

what is the MHRA alert for sodium valproate?

teratogenic → affects males and females

• new rule saying sodium valproate should not be initiated in any patients under 55 yrs of age unless 2 specialists independently review and document there is no other effective or tolerated treratment

• males under 55 already on sodium valproate can continue, for females pregnancy prevention programme must be met and annual risk acknowledgement form must be signed

what MHRA warning has been issued for all antiepileptic drugs?

all are associated with a slight increase in suicidal thoughts and behaviour → symptoms begin as early as 1 week after starting treatment

why should you take care when switching between different manufacturers’ products of a particular antiseizure medication?

loss of seizure control and/or worsening of side effects have been observed when switching from branded to generic

what is used to help decide if it is necessary to maintain continuity of supply of a specific manufacturers’ product for a specific antiepileptic drugs?

category system

• patients on category 1 drugs should be maintained on a specific manufacturers’ product

• for patients on category 2 drugs, prescriber should use clinical judgement and discuss seizure frequency and treatment history with the patient

• for patients on category 3 drugs, usually unnecessary to maintain the person on a specific manufacturer's product unless there is patient anxiety, risk of confusion, or risk of dosing errors

• go to CKS to see list of drugs in each category

which are the 4 category 1 antiepileptic medications that should definitely be prescribed by brand name?

• phenytoin

• carbamazepine

• phenobarbital

• primidone

what is antiepileptic hypersensitivity syndrome?

rare but potentially fatal syndrome associated with some antiepileptic drugs (list on treatment summaries)

• rarely cross sensitivity may occur between some of these antiepileptics

• symptoms start usually after 1-8 weeks of exposure → fever, rash, lymphadenopathy (swollen lymph glands)

• if signs occur, drug should be discontinued immediately

• note: mild rashes are common side effect of all antiepileptics that resolves upon discontinuation

at what point is withdrawal from antiepileptic medication considered?

when a patient has been seizure free for at least 2 years

• assessment to determine the risk of seizure recurrence if antiepileptic drugs are discontinued should be carried out

• on patients with multiple antiepileptics, one should be withdrawn at a time

• avoid abrupt withdrawal → taper off over 3 months

in what ethnic backgrounds is phenytoin associated with an increased risk of serious skin reactions?

han chinese or thai background

in what ethnic backgrounds is carbamazepine associated with an increased risk of serious skin reactions?

han chinese, thai, european or japanese background

what is long term treatment with some antiseizure medications associated with?

decreased bone mineral density and increased risk of osteomalacia

• consider vitamin D and calcium supplementation

what is the effect of some antiseizure medications on the effectiveness of hormonal contraceptives?

reduces effectiveness

what antiepileptic medication is affected by oestrogen containing hormonal contraceptives and HRT?

lamotrigine

what are extrapyrimidal side effects?

drug induced movement disorders

• mainly from antipsychotics

what are the different types of exrapyrimidal side effects?

• dystonia → involuntary spasms

• psuedoparkisonism → tremor, bradykinesia, rigidity

• akathisia → motor restlessness

• tardive dyskinesia → occurs with prolonged use and is characterised by involuntary movements usually of the face e.g. lip smacking — drug should be discontinued on appearance ce of early signs and withdrawal can sometimes make it worse

when are long acting formulations clinically appropriate for neurological and mental health patients?

• when long term consistent medication delivery is required

• address challenged with patient adherence

which neurological conditions routinely use long acting formulations?

• schizophrenia

• bipolar disorder (injectables)

• MS

• ADHD

• parkinsons (patches)

• substance use disorders

why are long acting formulations sometimes not preferred for neurological patients?

• challenges in managing potential severe side effects

• limited flexibility in dose adjustment

• long time required to achieve stable drug concentrations