Mood Stabilisers: Carbamazepine

Question 1

What is the indication of carbamazepine?

Answer 1

Mania ( not first-line ), prophylaxis of bipolar affective disorder unresponsive to lithium. Alcohol withdrawal.

Question 2

What is the mechanism of action of carbamazepine?

Answer 2

Carbamazepine blocks voltage-dependent sodium channels, and therefore inhibits repetitive neuronal firing. It ↓ glutamate release and ↓ turnover of dopamine and noradrenaline.

Question 3

What are the side effects of carbamazepine?

Answer 3

GI disturbances, dermatitis, dizziness, hyponatraemia, blood disorders e.g. leucopenia, thrombocytopenia.

Question 4

What are the contraindications of carbamazepine?

Answer 4

Caution in cardiac disease and blood disorders. Contraindicated in AV conduction abnormalities and acute porphyria. Avoid in pregnancy (can cause neural tube defects in the fetus).

Is a potent enzyme inducer so drugs such as COCPs will be metabolised faster. If the COCP is being used as a contraceptive, other methods should be considered.

Question 5

What effect does carbamazepine have on other drugs?

Answer 5

Is a potent enzyme inducer so drugs such as COCPs will be metabolised faster. If the COCP is being used as a contraceptive, other methods should be considered.

Question 6

What monitoring is required for carbamazepine?

Answer 6

Check WCC after a week. Measure plasma carbamazepine levels if signs of toxicity. LFTs and U&Es (hyponatraemia). Baseline measure of weight is desirable.

Question 7

What is the dose of carbamazepine?

Answer 7

Start at 400 mg daily in divided doses. Build up (max 1.6 g/day).

Question 8

What is the route of carbamazepine?

Answer 8

Oral.