Antiepileptics

Question 1

Sodium valproate:

Is contraindicated in children

Answer 1

False. Valproate can be safely used in children down to 1 month of age.

Question 2

Sodium valproate:

Is used to treat petit mal seizures

Answer 2

True. It is used to treat generalised, mixed and partial seizures.

Question 3

Sodium valproate:

Is used to treat grand mal seizures

Answer 3

True

Question 4

Sodium valproate:

Can be used safely in liver disease patients

Answer 4

False. It is contraindicated in severe hepatic or renal failure.

Question 5

Sodium valproate:

Acts by enhancing concentrations of the neurotransmitter GABA

Answer 5

True. Sodium valproate acts by weakly blocking sodium ion channels. It inhibits GABA transaminase, which would deactivate gamma-Aminobutyric Acid (GABA) and may also stimulate GABA synthesis.

Question 6

Valproic acid:

Is metabolised in the liver

Answer 6

True. 75% is metabolised by the CYP450 system.

Question 7

Valproic acid:

Is a liquid fatty acid at room temperature

Answer 7

True. Valproate is a liquid at room temperature but can be reacted with a base to form a solid salt.

Question 8

Valproic acid:

Enhances platelet aggregation

Answer 8

False. Valproate interferes with platelet aggregation and can cause blood dyscrasias.

Question 9

Valproic acid:

Takes at least 3 weeks to have it’s effect

Answer 9

False. It is effective 14 days after treatment commences.

Question 10

Valproic acid:

Has been used to treat migraines

Answer 10

True. Though mainly in the US.

Question 11

Phenytoin:

Inhibits the enzyme intestinal conjugase

Answer 11

True. Phenytoin does inhibit intestinal conjugase, which causes folate deficiency, not vitamin B2 deficiency.

Question 12

Phenytoin:

Has a half life of about 4hrs

Answer 12

False. Phenytoin’s half life is 6 to 24 hours.

Question 13

Phenytoin:

Is an CYP450 enzyme inhibitor

Answer 13

False. It is an enzyme inducer.

Question 14

Phenytoin:

Can cause Vitamin B2 deficiency

Answer 14

False

Question 15

Phenytoin:

Causes hypotension

Answer 15

True. When administered IV, Phenytoin can cause hypotension and arrhythmias and should be administered with cardiac monitoring.

Question 16

Phenytoin:

Does not cause glycosuria

Answer 16

False. Phenytoin can cause hyperglycaemia & glycosuria due to insulin inhibition.

Question 17

Phenytoin:

Is highly protein bound

Answer 17

True. It is mainly bound to Albumin.

Question 18

Phenytoin:

Undergoes zero order kinetics with a wide therapeutic index

Answer 18

False. Phenytoin follows saturatable first order kinetics which converts to zero order kinetics when the enzyme system is overwhelmed. It has a narrow therapeutic index and blood levels are therefore monitored.

Question 19

Phenytoin:

Toxicity can cause diminished tendon reflexes

Answer 19

False. Toxicity causes blurred vision, mydriasis and brisk tendon reflexes.

Question 20

Phenytoin:

Oral bioavailability is high and absorption is rapid

Answer 20

False. Bioavailability is good, but oral absorption is slow, variable & can be only partial. Volume of distribution is approx 70% of body weight.

Question 21

Phenytoin:

Causes megaloblastic anaemia due to Vitamin B12 deficiency

Answer 21

False. Phenytoin causes macrocytic, megaloblastic anaemia due to folate deficiency.

Question 22

Phenytoin:
Is a class Ia antiarrhythmic

Answer 22

False. It is a class Ib antiarrhythmic agent, like Lidocaine.

Question 23

Phenytoin:

Has no effect on Thyroid function

Answer 23

True. Causes falsely low TFTs after long term treatment.

Question 24

Phenytoin:

Is absorbed rapidly via IM or IV routes

Answer 24

False. Not effective IM, only PO (slowly) and IV.

Question 25

Phenytoin: | Phenyotin is carcinogenic

Answer 25

False. There is no good evidence that Phenytoin is carcinogenic.

Question 26

Phenytoin: | Can be used to treat Digoxin induced dysrhythmias

Answer 26

True

Question 27

Phenytoin: | Is metabolised in the liver by the enzyme rhodanase

Answer 27

False. Phenytoin is metabolised by hepatic microsomal enzymes.

Question 28

Phenytoin: | Can cause significant side effects including nystagmus

Answer 28

True. It can cause horizontal gaze nystagmus, gum overgrowth, acne as well as blood disorders.

Question 29

Phenytoin: | Is effective with the oral contraceptive pill

Answer 29

True. Phenytoin is effective in the presence of the OCP but the contraceptive effect may not be effective due to enzyme induction.

Question 30

Phenytoin: | Stabilises excitable membranes

Answer 30

True

Question 31

Phenobarbitone/Phenobarbital: | Is the most widely used anticonvulsant

Answer 31

False.

Question 32

Phenobarbitone/Phenobarbital: | Lasts longer than Phenytoin

Answer 32

True. Phenobarbital is extremely long acting, with a half life of 50 - 100 hours or more.

Question 33

Phenobarbitone/Phenobarbital: | Is used in the treatment of generalised seizures

Answer 33

True. It is effective in all seizure activity except absence seizures.

Question 34

Phenobarbitone/Phenobarbital: | Is ineffective in absence seizures

Answer 34

True.

Question 35

Phenobarbitone/Phenobarbital: | Is highly protein bound

Answer 35

False. Protein binding is in the order of 20 - 45%.

Question 36

Phenytoin is safe in pregnancy

Answer 36

False. Phenytoin is teratogenic and can cause Fetal Hydantoin Syndrome (like Carbamazepine).

Question 37

Fetal Hydantoin syndrome is associated with Carbamazepine treatment only

Answer 37

False. FHS causes intra-uterine groth retardation, microcephaly, craniofacial abnormalities and limb defects.

Question 38

Phenobarbital is also a sedative agent

Answer 38

True. Use of Phenobarbital as a sedative has largely been superceded by benzodiazepines.

Question 39

Phenytoin act to stabilise active voltage gated sodium channels in the CNS

Answer 39

False. Phenytoin stabilises sodium channels in their inactive state

Question 40

Phenytoin can cause skin rashes

Answer 40

True.

Question 41

Phenytoin only very rarely provokes an allergic reaction

Answer 41

False. Phenytoin can cause severe allergic reactions and must be given with vigilance.

Question 42

Phenytoin is mainly excreted unchanged in the urine

Answer 42

False. Primarily, Phenytoin is initially excreted in the bile as inactive metabolites and reabsorbed before being excreted in the urine. Only a small amount is excreted unchanged renally.

Question 43

Phenytoin can be used to treat trigeminal neuralgia

Answer 43

True

Question 44

Sodium valproate can cause tremors

Answer 44

True

Question 45

10% of people treated with Sodium valproate experience hair loss

Answer 45

True

Question 46

Carbamazepine: | Is safe in pregnancy

Answer 46

False. Carbamazepine can cause spina bifida & other neurodevelopmental problems after intrauterine exposure.

Question 47

Carbamazepine: | Can be used in chronic pain

Answer 47

True

Question 48

Carbamazepine: | Has a short half life

Answer 48

False. Half life is in the order of 25 - 65 hours

Question 49

Carbamazepine: | Can cause severe thrombocytopenia

Answer 49

True. Carbamazepine can reduce serum sodium & WBC levels at normal drug levels, but also cause life-threatening loss of platelets.

Question 50

Carbamazepine: | Increases the risk of developing Lupus in women

Answer 50

True. Lupus risk increases by nearly 90% (probably only in women).