6.6 Antianxiety Medications

Selective serotonin reuptake inhibitors (SSRIs) and other antidepressants are used to treat anxiety and anxiety disorders as mainstays however, other more rapidly acting antianxiety medications help reduce anxiety, panic attacks, or extreme fear and worry in the present moment and assist with decreasing agitation in psychotic disorders, such as schizophrenia. The most common class of antianxiety medications is benzodiazepines. Beta-blockers, buspirone, and hydroxizine may also be prescribed for anxiety.^[1]

Benzodiazepines

Benzodiazepines are used to treat anxiety and are also used for their sedation and anticonvulsant effects because they bind to GABA receptors and stimulate the effects of GABA (an inhibitory neurotransmitter). Benzodiazepines include clonazepam, alprazolam, and lorazepam. Benzodiazepines are a Schedule IV controlled substance because they have a potential for misuse and can cause dependence. Short-acting benzodiazepines (such as lorazepam) xxxxxxxx. Lorazepam is available for oral, intramuscular, or intravenous routes of administration and is frequently used in behavioral health settings.^[2] Benzodiazepines are also useful in withdrawal from alcohol to lower the risk of seizures and lessen agitation. Ultra-short acting formulations may be used prior to procedures, such as surgery, to lessen anxiety.

Beta-Blockers

Beta-blockers (such as propranolol) block sympathetic nervous system stimulation of Beta-1 receptors. They may be prescribed to manage the physical symptoms of anxiety (such as trembling, rapid heartbeat, and sweating) for a short period of time or used “as needed” to reduce acute physical symptoms.^[3] Beta-blockers play an important role in the treatment of patients with post-traumatic stress disorder. Propranolol has also been studied for use after the immediate experience of potentially traumatic events to prevent consolidation of traumatic memories to interfere with and weaken the emotional intensity associated with traumatic memories to potentially prevent PTSD symptoms.

Buspirone

Buspirone is classified in the azapirone drug class. It has a strong affinity for serotonin 5HT1a receptors. There is no effect on benzodiazepine GABA receptors. The underlying mechanism behind how the partial 5HT1a agonism translates into clinical results remains largely unknown. It is proposed from increased serotonergic activity in the amygdala and other parts of the brain’s anxiety/fear circuitry. Due to the delayed anxiolytic effects seen clinically, buspirone likely provides relief through adaptations in 5HT1a receptors. Buspirone is primarily used to treat generalized anxiety disorder; however, it appears that buspirone may be useful in various other neurological and psychiatric disorders. Examples include attenuating side effects of Parkinson’s disease therapy, ataxia, depression, social phobia, behavior disturbances following brain injury, and those accompanying Alzheimer disease, dementia, and attention deficit disorders.^[4]

Hydroxyzine

Hydroxyzine (Vistaril) is an H-1 antihistamine capable of crossing the blood-brain barrier into the central nervous system (CNS) useful for insomnia anxiety, and panic attacks. Due to anticholinergic properties, dry mouth is a relatively common adverse effect.^[5] Hydroxyzine is the most studied antihistamine for anxiety and the only antihistamine which is FDA-approved for use in anxiety. Hydroxyzine is used as an alternative to the benzodiazepines both inpatient and outpatient settings, in part, due to lack of misuse potential. Hydroxyzine and other antihistamines like diphenhydramine may also be safer to use in children and adolescents and in pregnant women. There is, however, concern about the risk of anticholinergic toxicity or delirium in the elderly or patients with neurocognitive disorders. Antihistamines are generally well-tolerated, aside from adverse effects like dry mouth, constipation, sedation, and risks of use while driving. The primary drawback to this medication class is that patients tend to develop tolerance to antihistamines over time.^[6]