Summary of possible benefits and harms

How well does carbamazepine work?

Four small, short-term studies have looked at how well carbamazepine manages aggression and agitation in people with dementia. All the studies used aggression or behaviour rating scales to find out whether symptoms improved with carbamazepine. The results did not all agree. Overall, 2 studies showed that carbamazepine improved symptoms more than placebo (dummy tablets), but 2 others didn't.

One study included 19 women with dementia who were also wandering, restless or physically aggressive. It found that taking carbamazepine for 4 weeks did not improve behaviour rating scores compared with placebo (dummy tablets).

A second study included 6 people with severe Alzheimer's disease (a type of dementia) who were aggressive. In this study, taking carbamazepine for 8 weeks reduced aggression more than taking placebo.

Another study included 21 people with severe Alzheimer's disease who had been very agitated for over 1 month and whose symptoms had not improved with antipsychotic medicines. The study found that, over 6 weeks, there was no difference in overall behaviour rating scores between people taking carbamazepine and those taking placebo. However, people taking carbamazepine showed less hostility than those taking placebo.

The largest study included 51 people with severe Alzheimer's disease or other type of dementia, who had been agitated for at least 2 weeks. In this study carbamazepine was better than placebo for improving overall behaviour scores after 6 weeks, mainly because of improvements in agitation and hostility. Carbamazepine also improved other measures of aggression and behaviour more than placebo.

All the studies were short and no information is available on how well carbamazepine works in the long term for managing aggression and agitation in people with dementia. Also, all studies compared carbamazepine with placebo so it is not known how carbamazepine compares with other medicines used for dementia. The average age of people in the studies was 79 years, and most were women with severe dementia. Therefore, it isn't clear how well carbamazepine works in younger people, men or people with less severe dementia.

What are the possible harms or side effects?

In 3 studies, carbamazepine treatment was tolerated well (with few side effects) but in 1 study people had more problems with side effects. In the largest study, side effects were more common with carbamazepine (occurring in 16 out of 27 people) than with placebo (7 out of 24 people). In the second largest study, side effects occurred in 4 out of 9 people taking carbamazepine and 8 out of 12 people taking placebo.

The following common side-effects (occurring in 1 in 100 people or more) may occur when taking carbamazepine, particularly at first, although some of these usually settle down over time:

  • dizziness and problems with balance and coordination

  • tiredness and feeling sleepy

  • headache

  • blurred or double vision

  • feeling sick and being sick

  • water retention

  • allergic skin reactions.

Carbamazepine sometimes causes blood disorders called leukopenia, thrombocytopenia and eosinophilia. Doctors can advise what signs to look out for.

Please note that the results of the research studies only indicate the benefits and harms for the population in the studies. It is not possible to predict what the benefits and harms will be for an individual patient being treated with carbamazepine.