The anxiety disorders, obsessive compulsive disorder (OCD) and post-traumatic stress disorder (PTSD) are common and debilitating,
often coexist with medical and psychiatric conditions, and usually require long-term treatment. Effective anxiolytic drugs include the
selective serotonin reuptake inhibitors (SSRIs) and the serotonin and noradrenaline reuptake inhibitors (SNRIs), which are the preferred
agents in primary care. Patients who fail to respond adequately to these may benefit from second-line tricyclic antidepressants or
monoamine oxidase inhibitors. Alternative antidepressants include agomelatine and mirtazapine. Benzodiazepines, the anti-epileptic
agent, pregabalin, and atypical antipsychotics are generally reserved for specialist use. The 5-HT1A agonist, buspirone, and the
antihistamine, hydroxyzine, may also be useful, although the evidence for their efficacy covers a very narrow spectrum. This review
describes the pharmacology of these anxiolytics and provides updated evidence for their use in the anxiety and related disorders.