148 - How common are disinhibitory reactions with b

How common are disinhibitory reactions with benzodiazepines?

472 The Maudsley® Prescribing Guidelines in Psychiatry CHAPTER 3 short-­acting drugs given intravenously are extremely likely to cause disinhibition in personality disorder. What is the mechanism? Various theories of the mechanism have been proposed.19,23–25 First, the anxiolytic and amnesic properties of benzodiazepines may lead to a loss of the restraint that governs normal social behaviour. Second, the sedative and amnesic properties of benzodiazepines may lead to a reduced ability to concentrate on the external social cues that guide appropriate behaviour. Last, benzodiazepine-­mediated increases in GABA neurotransmission may lead to a reduction in the restraining influence of the cortex, resulting in untrammelled excitement, anxiety and hostility. Flumazenil is usually used to reverse benzodiazepine sedation and respiratory depression, but it is also effective in treating disinhibition reactions.26 Subjective reports People who take benzodiazepines rate themselves as being more tolerant and friendly, but respond more to provocation than patients treated with placebo.27 People with impulse control problems who take benzodiazepines may self-­report feelings of power and overwhelming self-­esteem.18 Psychology rating scales demonstrate increased suggestibility, failure to recognise anger in others and reduced ability to recognise social cues. The patient is usually completely unaware that their behaviour is bizarre or that it is the result of drug-­induced disinhibition. Clinical implications Benzodiazepines are frequently used in rapid tranquillisation and the short-­term management of disturbed behaviour. For the vast majority of treatment episodes, benzodiazepines produce sedation and reductions in anxiety and aggression. It is important to be aware, nonetheless, of their propensity to cause paradoxical disinhibitory reactions. Suspected paradoxical reactions should be clearly documented in the clinical notes. In extreme cases, flumazenil can be used to reverse the reaction although its use is not without its own dangers (agitation, arrythmia, convulsions).28 If the benzodiazepine was prescribed to control acute behavioural disturbance, future episodes should be managed with antipsychotic drugs29 or other non-­benzodiazepine sedatives. Paradoxical disinhibitory/aggressive outbursts in the context of benzodiazepine use: ■ ■Rare in the general population but more frequent in people with impulse control problems or central nervous system damage and in the very young or very old. ■ ■Most often associated with high oral doses of high-­potency drugs or with any dose of any drug administered parenterally. ■ ■Usually occur in response to (often very mild) provocation, the exact nature of which is not always obvious to others. ■ ■Recognised by others but often not by the sufferers, who often believe that they are friendly and tolerant.