Beta-blockers may improve agitation, anxiety and aggressive symptoms following brain injury, as well as to reduce restlessness; however dosage is often high, leaving patients vulnerable to such adverse effects as sedation, depression and lethargy, although it does not seem to negatively affect motor recovery post-injury 3.
What beta-blockers are used to treat aggression and why?
- Propanolol and Pindol are the two beta-blockers used because they both cross the blood-brain barrier.
How do beta-blockers work to treat aggression following an ABI?
- Beta-blockers work to improve agitation, anxiety, aggressive behaviour and restlessness, likely through reduction of sympathetic activity.
Pindololis a beta-blocker unlike many others in that it exerts a partial agonist effect, providing a slight stimulation of the blocked receptor and maintaining a better resting sympathetic tone.
- Propranololis a non-selective beta-blocker that has been used for the reduction of aggressive behaviours associated with compromised brain function. It is not known how this drug works to affect behaviour, however it appears to lack the serious cognitive and affective side effects of other medications or physical restraints used to treat agitation post-injury 3.
What is the evidence for beta-blockers in the management of aggression post ABI?
There is Level 1 evidence that pindolol and propanolol improves aggression following brain injury.
- Overall, beta-blockers improve aggressive behaviour following brain injury.
Greendyke & Kanter 34investigated the effectiveness of the beta-blocker, pindolol, for the improvement of behaviour associated with brain disease in a randomized, crossover trial. A significant reduction in assaultive behaviour was demonstrated during treatment with pindolol. In another study byGreendyke 35investigated the effectiveness of the beta-blocker, propranolol, for the improvement of behaviour associated with brain disease in a randomized, crossover trial.
Of the nine patients involved in the, five showed marked improvement, two demonstrated moderate improvement, and two showed little or no improvement of assaultive behaviour.
Following the acute stage of recovery, 21 closed-head-injured (CHI) patients were treated with a maximum dose of 420 mg/day of propranolol 36.
- The intensity of agitated symptoms decreased but not the frequency,suggesting that the drug helps to reduce the emotional intensity of agitated responses.
For a more detailed discussion please see ERABI/Mental Health Issues Post ABI.