Epilepsy and Other Seizure Disorders Flashcards Preview

A - BNF Chapter 4 - CNS COPY > Epilepsy and Other Seizure Disorders > Flashcards

Flashcards in Epilepsy and Other Seizure Disorders Deck (106)
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1
Q

What is the main aim of epilepsy treatment?

A

To prevent the occurrence of seizures by maintaining an effective dose of one or more antiepileptic drugs.

2
Q

Why should dosage frequency of antiepileptic drugs be kept as low as possible?

A

To promote adherence.

3
Q

Why may large doses of antiepileptic drugs require frequent dosing?

A

To avoid adverse effects associated with high plasma-drug concentrations.

4
Q

Why is monotherapy with a first- or second-line antiepileptic drug preferred in the treatment of epilepsy?

A

The concurrent use of multiple antiepileptic drugs increases the risk of adverse reactions and drug interactions.

5
Q

When switching from one antiepileptic drug to another, what should be done?

A

The first drug should be slowly withdrawn.

6
Q

What may be associated with (although it is not excluded to) the switching of a patient from one antiepileptic product to another, including of different brands?

A

Loss of seizure control and/or worsening of side-effects.

7
Q

Into how many risk-based categories has the MHRA separated antiepileptic drugs into? What do these categories show?

A

Three. They show how necessary it is to main continuity of supply of a manufacturer’s product.

8
Q

If a patient is maintained on a specific manufacturer’s product, how should this be prescribed?

A

Either by specifying a brand name or by using the generic drug name and name of the manufacturers.

9
Q

For what indication is the MHRA advice on maintaining specific products of antiepileptic drugs relative to?

A

Epilepsy.

10
Q

How should suspected adverse reactions to antiepileptic drugs be reported?

A

On an MHRA Yellow Card.

11
Q

When may it be necessary to dispense a product from a different manufacturer?

A

When there are supply problems, in order to maintain treatment continuity.

12
Q

What are the three risk-based categories for antiepileptic drugs?

A

Patient should be maintained on a specific brand. Supply of a specific brand based on clinical judgement. Unnecessary to supply a specific brand.

13
Q

For which antiepileptic drugs should a patient be maintained on a specific brand?

A

Phenytoin, carbamazepine, phenobarbital, primidone.

14
Q

For which antiepileptic drugs should supply of a specific brand be based upon clinical judgement?

A

Valproate, lamotrigine, perampanel, retigabine, rufinamide, clobazam, clonazepam, oxcarbazepine, eslicarbazepine, zonisamide, topiramate.

15
Q

For which antiepileptic drugs is it unnecessary to supply a specific brand?

A

Levetiracetam, lacosamide, tiagabine, gabapentin, pregabalin, ethosuximide, vigabatrin.

16
Q

Antiepileptic drugs are associated with a small increase in risk of what psychological side effect?

A

Suicidal thoughts and behavior.

17
Q

If a patient on antiepileptic drugs develops suicidal thoughts and behaviors, what should they do?

A

Seek medical advice.

18
Q

How soon since starting antiepileptic drug treatment may patients experience suicidal thoughts and behaviours?

A

As soon as one week after starting treatment.

19
Q

Abrupt withdrawal of antiepileptic drugs should be avoided. How should antiepileptic drugs be withdrawn?

A

Reduction in dosage should be gradual.

20
Q

How long can it take for the withdrawal of barbiturates?

A

Months.

21
Q

What is the main risk with withdrawal of antiepileptic drugs?

A

Significant seizure recurrence.

22
Q

If a patient is having multiple antiepileptic drugs withdrawn, how should this be done?

A

One at a time.

23
Q

What vehicles can patients with epilepsy drive?

A

They can drive vehicles apart from large goods vehicles or passenger vehicles.

24
Q

What conditions must be satisfied before a patient with epilepsy can drive?

A

They must be seizure free for one year or have established a three-year period of asleep attacks without awake attacks.

25
Q

When does the DVLA recommend that patients with epilepsy do not drive?

A

Patients with epilepsy should not drive during medication changes, withdrawal of medication, or 6 months afterwards.

26
Q

Which antiepileptic drugs are associated with an increased risk of teratogenicity?

A

Valproate, phenytoin, primidone, phenobarbital, lamotrigine, carbemazepine.

27
Q

Which antiepileptic drug is associated with the greatest risk of congenital malformations and long-term developmental disorders?

A

Valproate.

28
Q

In which patients should valproate not be used unless there is no safer alternative?

A

Pregnant women, female children, women of childbearing potential.

29
Q

What is required when valproate is required in pregnancy?

A

Specialist monitoring.

30
Q

What teratogenic malformation is associated with topiramate use and when is it likely to occur?

A

An increased risk of cleft palate when taken in the first trimester of pregnancy.

31
Q

What advice should be given to pregnant women who also have epilepsy?

A

Advice about effective contraception methods to avoid unplanned pregnancies. Women who want to become pregnant should be referred to a specialist.

32
Q

What is the likelihood of a woman who is taking antiepileptic drugs having a baby with no malformations?

A

At least 90%. It is important not to stop taking essential treatment.

33
Q

In the case of women who are treated with sodium valproate or valproic acid, who become pregnant, what course of action is required?

A

An urgent consultation is required to reconsider the benefits and risks of valproate therapy.

34
Q

When is folate supplementation advised in pregnancy? Why?

A

Before conception and throughout the first trimester.

35
Q

For what should women who have seizures during the second half of the pregnancy be assessed for before changing any treatment for epilepsy?

A

Eclampsia.

36
Q

Routine injection of which vitamin at birth minimizes the risk of neonatal hemorrhage associated with antiepileptic drugs?

A

Vitamin K.

37
Q

What effects may be seen in babies born to women who have been taking antiepileptic drugs?

A

Withdrawal effects.

38
Q

Can mothers on antiepileptic drugs breastfeed?

A

Yes.

39
Q

What should babies born to mothers taking antiepileptic drugs be monitored for?

A

Sedation, feeding difficulties, adequate weight gain, developmental milestones, adverse effects associated with the specific antiepileptic drug.

40
Q

If suspected adverse reactions to antiepileptic drugs occur in breastfed children, what monitoring should be carried out?

A

Serum-drug concentration.

41
Q

If toxicity to an antiepileptic drug occurs in breastfed children, what course of action may be required?

A

The introduction of formula feeds to limit drug exposure or weaning off of breastmilk altogether.

42
Q

What is antiepileptic hypersensitivity syndrome?

A

A rare but potentially fatal syndrome associated with some antiepileptic drugs.

43
Q

What drugs are associated with an increased risk of antiepileptic hypersensitivity syndrome?

A

Carbamazepine, lacosamide, lamotrigine, oxcarbazepine, phenobarbital, phenytoin, primidone, rufinamide.

44
Q

How long after exposure to a specific antiepileptic drug may patients experience the symptoms of antiepileptic hypersensitivity syndrome

A

Between 1 and 8 weeks.

45
Q

What are the symptoms of antiepileptic hypersensitivity syndrome?

A

Fever, rash, lymphadenopathy, liver dysfunction, hematological, renal, and pulmonary abnormalities, vasculitis, multiorgan failure.

46
Q

What action should be taken if signs or symptoms of antiepileptic hypersensitivity syndrome occur?

A

The drug should be withdrawn immediately and expert advice should be sought.

47
Q

What are the two main types of seizures?

A

Focal and generalised.

48
Q

How can focal seizures be further categorized?

A

Simple partial seizures and complex partial seizures.

49
Q

Define focal seizures.

A

Seizures where mall parts of the brain are affected.

50
Q

Define simple partial seizures.

A

Focal seizures where the patient remails conscious throughout the seizure.

51
Q

Define complex partial seizures.

A

Focal seizures where the patient loses awareness and cannot remember what happened after the seizure has passed.

52
Q

Define generalized seizures.

A

Seizures where most or all of the brain is affected.

53
Q

How can generalized seizures be further categorized?

A

Absence seizures, myoclonic seizures, clonic seizures, atonic seizures, tonic seizures, tonic-clonic seizures.

54
Q

Define absence seizures.

A

Seizures where the patient loses awareness of their surroundings, usually for up to 15 seconds.

55
Q

Define myoclonic seizures.

A

Seizures causing the patient’s arms, legs or upper body to jerk or twitch.

56
Q

Define clonic seizures.

A

Similar twitching of the arms, legs or upper body as myoclonic seizures except for longer. May last for up to two minutes. Loss of consciousness may occur.

57
Q

Define atonic seizures.

A

Seizures where all of the muscles suddenly relax, resulting in possible injury due to a fall.

58
Q

Define tonic seizures.

A

Seizures where all of the muscles become stiff, resulting in possible injury from a fall.

59
Q

Define tonic-clonic seizures.

A

Seizures with two stages. First the muscles go stiff then the arms and legs begin twitching. Can last a few minutes.

60
Q

Define status epilepticus.

A

Any seizure lasting longer then 30 minutes or a series of seizures where the patient does not regain consciousness between seizure. MEDICAL EMERGENCY.

61
Q

What is the mechanism of action for carbamazepine?

A

Inhibits voltage gated sodium channels, thus preventing repetitive firing of action potentials.

62
Q

What is the therapeutic range of carbamazepine?

A

4-12 mg/L (20-50 micromol/L).

63
Q

Should carbamazepine used for epilepsy treatment be prescribed by brand?

A

Yes.

64
Q

What are the symptoms of carbamazepine toxicity?

A

Incoordination, blurred vision, double vision, drowsiness, nystagmus, ataxia, arrhythmias, N&V, diarrhoea, hyponatraemia.

65
Q

What are the side effects of carbamazepine?

A

Toxicity, blood disorders, skin disorders, hepatic disorders, antiepileptic hypersensitivity syndrome.

66
Q

What blood disorders are associated with carbamazepine use?

A

Fever, sore throat, unexplained bleeding or bruising.

67
Q

What skin disorders are associated with carbamazepine use?

A

Mouth ulcers, rash.

68
Q

What are the symptoms of hepatic disorder associated with carbamazepine use?

A

Severe GI upset, fatigue, jaundice, dark urine.

69
Q

What monitoring is required with carbamazepine use?

A

Plasma concentration (measured after 2 weeks to ensure within therapeutic range), FBC, renal and hepatic function.

70
Q

How does hepatic impairment effect carbamazepine use?

A

Metabolism is impaired in advanced liver disease; dose increase may be needed.

71
Q

Increases in carbamazepine concentration may be seen when used with which drugs?

A

Acetazolamide, cimetidine, clarithromycin, erythromycin.

72
Q

Decreases in carbamazepine concentration may be seen when used with which drugs?

A

Phenytoin, rifabutin, St. John’s Wort.

73
Q

Carbamazepine reduces the plasma concentration of which drugs?

A

Antipsychotics, corticosteroids, coumarins, eplerenone, oestrogens, progestogens, simvastatin.

74
Q

There is a possible increase in risk of convulsions when antiepileptics are given with which drug?

A

Orlistat.

75
Q

Fosphenytoin is a prodrug form of which antiepileptic drug?

A

Phenytoin.

76
Q

IV infusion of fosphenytoin is associated with which severe cardiovascular symptoms?

A

Asystole, ventricular fibrillation, cardiac arrest. Hypotension, bradycardia, and heart block have also been reported.

77
Q

What steps are recommended when administering fosphenytoin via IV infusion?

A

Monitor HR, BP, and respiratory function during the infusion. Observe the patient for at least 30 minutes after infusion. If hypotension occurs, reduce the infusion rate or withdraw the drug. reduce dose or infusion rate in the elderly and in renal & hepatic impairment.

78
Q

What safety warning comes with the use of gabapentin oral solution (Rosemont brand) in adolescents or young adults with a low body weight (39-50 kg)?

A

May exceed WHO recommended limits of propylene glycol, acesulfame K and saccharin.

79
Q

What symptoms suggestive of bone marrow failure should patients and carers of patients on lamotrigine be made aware of?

A

Anaemia, bruising, or infection.

80
Q

Which conditions have been rarely associated with lamotrigine use?

A

Aplastic anaemia, bone-marrow depression, pancytopenia.

81
Q

Which serious skin reactions have been reported in the first 8 weeks of lamotrigine use?

A

Stephen-Johnson’s syndrome and toxic epidermal necrolysis.

82
Q

What factors increase one’s risk of developing Stephen-Johnson’s syndrome, toxic epidermal necrolysis, etc when taking lamotrigine?

A

Concomitant use of valproate, initial lamotrigine dosing higher than recommended, more rapid dose escalation than recommended.

83
Q

If a patient develops a rash when taking lamotrigine, what may be the cause? What course of action should be taken if this is the case?

A

Hypersensitivity. Consider withdrawal if rash of signs of hypersensitivity syndrome develop.

84
Q

What is the mechanism of action of phenytoin?

A

Inhibition of voltage-gated sodium channels, thus preventing repetitive firing of action potentials.

85
Q

What is the therapeutic range of phenytoin?

A

10-20 mg/L (40-80 micromol/L).

86
Q

Which brand specific category does phenytoin fall into? What does this mean?

A

One. Patient’s must be maintained on the same brand.

87
Q

Describe the kinetics of phenytoin?

A

Non-linear.

88
Q

Preparations containing phenytoin sodium and phenytoin base are not equivalent. 100mg of phenytoin sodium is equivalent to how much phenytoin base?

A

92mg. When switching doses this may be clinically significant.

89
Q

Give some of the warning symptoms associated with phenytoin use.

A

Toxicity, skin disorders, hepatotoxicity, blood disorders, suicidal thoughts, low levels of vitamin D.

90
Q

Give some of the symptoms of phenytoin toxicity.

A

Nystagmus, double vision, slurred speach, ataxia, confusion, hyperglycaemia.

91
Q

Give some of the symptoms of the skin disorder sometimes seen with phenytoin use.

A

Rash, toxic epidermal necrolysis.

92
Q

Give some of the symptoms of the hepatotoxicity sometimes seen with phenytoin use.

A

Jaundice, GI pain, dark urine.

93
Q

Give some of the symptoms of the blood disorders sometimes seen with phenytoin use.

A

Bleeding, bruising, fever, malaise, mouth ulcers, sore throat.

94
Q

What are some of the consequences of low vitamin D levels?

A

Rickets in children, osteomalacia in adults.

95
Q

Increased plasma concentrations of phenytoin are seen with concomitant use of which drugs?

A

Amiodarone, chloramphenicol, cimetidine, disulfiram, diltiazem, fluconazole, fluoxetine, miconazole, topiramate, trimethoprim.

96
Q

Reduced plasma concentrations of phenytoin are seen with concomitant use of which drugs?

A

Rifamycins, St John’s Wort, theophylline, itraconazole, ciclosporin.

97
Q

When does liver dysfunction associated with sodium valproate usually occur and what is it also further associated with?

A

Usually occurs in the first 6 months of therapy. Often associated with multiple antiepileptic therapy.

98
Q

Raised liver enzymes when using sodium valproate are usually transient however for how long should LFTs be performed?

A

Every 6 months until liver function returns to normal.

99
Q

When should sodium valproate treatment be immediately discontinued?

A

If abnormally prolonged prothrombin time persists or if signs of toxicity present (persistent vomiting and abdominal pain, jaundice, loss of seizure control).

100
Q

What visual disturbance may patients with secondary angle-closure glaucoma experience when taking topiramate? When does this typically occur?

A

Acute myopia (short sightedness), typically occurring within one month of starting treatment. Fluid build-up resulting in anterior displacement of the lens and iris have also been reported.

101
Q

If raised intra-ocular pressure occurs when a patient is taking topiramate, what course of action should be taken?

A

Seek specialist ophthalmological advice, use appropriate measures to reduce intra-ocular pressure, stop topiramate as rapidly as feasible.

102
Q

Visual problems associated with use of vigabatrin usually occur when?

A

From one month to several years after starting treatment.

103
Q

What may happen to the visual disturbances seen with vigabatrin use when the drug is discontinued?

A

They usually persist and further deterioration cannot be ruled out.

104
Q

What monitoring is required when a patient is taking vigabatrin?

A

Visual feild testing before treatment and at 6-monthly intervals.

105
Q

If a patient taking vigabatrin reports new visual symptoms, what course of action should be taken?

A

Symptoms must be reported and the patient should be reviewed by an ophthalmologist urgently. Gradual withdrawal of vigabatrin should be considered.

106
Q

When should benzodiazepines be administered for anaesthesia?

A

Only by or under the supervision of experienced personnel with adequate training in anaesthesia and airway management.