Carbamezapine

Question 1

indications for carbamezapine

Answer 1

1. seizure prophylaxis in epilepsy. first line for generalised tonic-clonic and focal seizures (not recommended in absence or myoclonic)
2. trigeminal neuralgia to control pain and reduce severity of attacks

Question 2

MOA of carbamezapine

Answer 2

inhibits neuronal sodium channels which stabilises resting membrane potentials and reduces neuronal excitability. blocks synaptic transmission

Question 3

adverse effect of carbamazepine (erythema nodosum)

Answer 3

skin rash, bruising, bleeding, high temp, mouth ulcers,

Question 4

carbamazepine side effects

Answer 4

GI upset (nausea, vomiting)
neurological effects (dizziness, ataxia)
oedema
hyponatraemia (ADH like effect)

Question 5

antiepileptic hypersensitivity syndrome

Answer 5

affects 1 in 5000 people taking carbamazepine usually within 2 months of starting treatment

lamotrigine/phenytoin

severe skin reaction- Steven Johnson syndrome, epidermal nacoolysis fever, lymphadenopathy with systemic involvement

Question 6

carbamazepine and pregnancy

Answer 6

exposure in utero is associated with neural tube defect, cardiac and urinary tract abnormalities and cleft palate

discuss with specialist if pregnancy and take high dose folic acid

induced CYP P450

Question 7

how is carbamazepine prescribed?

Answer 7

only available for oral or rectal administration. started at low dose 100-200mg once or twice daily.

increase gradually to maximum of 1.6g/day in divided dose if tolerance develops

immediate-modified release tablets, chewable tablets, oral suspension