Epilepsy medication

Question 1

1) How does sodium valproate work?
2) Name 3 adverse effects

Answer 1

1) Increasing the activity of GABA
2) Increased appetite and weight gain, alopecia,
P450 enzyme inhibitor, ataxia, tremor, hepatitis, pancreatitis, thrombocytopenia, teratogen

Question 2

1) How does carbamazepine work?
2) Name 3 adverse effects
3) Name a feature of Steven Johnson syndrome
4) Name 2 other drugs that can cause SJS

Answer 2

1) Binds to sodium channels increasing their refractory period
2) P450 enzyme inducer, dizziness and ataxia, drowsiness, agranulocytosis
syndrome of inappropriate ADH secretion,
visual disturbances, aplastic anaemia, Steven Johnson syndrome
3) Rash, mucosal involvement, fever, arthralgia
4) Allopurinol, phenobarbital, sulphonamide, lamotrigine, penicillins, OCP, NSAIDs, sertraline, phenytoin, imidazole (anti-fungal), salicylates, nevirapine

Question 3

1) How does phenytoin work?
2) Name 3 adverse effects

Answer 3

1) Binds to sodium channels increasing their refractory period
2) P450 enzyme inducer, dizziness and ataxia, drowsiness, hirsutism, megaloblastic anaemia,
peripheral neuropathy, enhanced vitamin D metabolism causing osteomalacia, lymphadenopathy, rashes

Question 4

1) How does ethosuximide work?
2) Name an adverse effect

Answer 4

1) Partial antagonism of T-type calcium channels
2) Night terrors and rashes

Question 5

Lamotrigine, topiramate, levetiracetam
1) How do these drugs work?
2) Name a side effect of lamotrigine
3) Name a side effect of levetiracetam

Answer 5

1) Block sodium channels
2) Stevens-Johnson syndrome
3) Depression, suicidal thoughts

Question 6

Benzodiazepines
1) How do they work?
2) As well as anticonvulsants, name another use for benzodiazepines
3) Why should they only be prescribed for a short period of time?
4) Name an example of a benzodiazepine
5) Name 2 side effects

Answer 6

1) Enhance the effect of the inhibitory neurotransmitter GABA by increasing the frequency of chloride channels
2) Sedation, hypnotic, anxiolytic, muscle relaxant
3) Patients commonly develop a tolerance and dependence
4) Diazepam, temazepam, midazolam, lorazepam, clonazepam
5) Daytime drowsiness, confusion, respiratory depression, tolerance, dependence

Question 7

Barbiturates
1) How do they work?
2) Name an example of a barbiturate
3) Name a side effect

Answer 7

1) Facilitate GABAa action by increasing the duration of chloride channel opening
2) Phenobarbital, thiopental
3) Sedation, respiratory depression