Anxiolytics. Muscle relaxants with central action.
Anxiolytics are medications used to reduce anxiety and alleviate symptoms of anxiety disorders, including generalized anxiety disorder (GAD), social anxiety disorder, panic disorder, and specific phobias. Some anxiolytics also have muscle relaxant properties, particularly benzodiazepines, which act centrally to reduce muscle tension.
Classification
- Benzodiazepines: Diazepam, Alprazolam, Clonazepam, Midazolam
- Selective Serotonin Reuptake Inhibitors (SSRIs) and Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Fluoxetine, Paroxetine, Venlafaxine
- Antiepileptics: Valproate, Gabapentin, Pregabalin
- Atypical Antipsychotics: Risperidone, Olanzapine
Pharmacodynamics
- Benzodiazepines: Enhance the effect of gamma-aminobutyric acid (GABA) at the GABA-A receptor, increasing chloride ion influx. This leads to hyperpolarization of the neuron, reducing neuronal excitability and producing sedative, anxiolytic, anticonvulsant, and muscle relaxant effects.
- SSRIs: Inhibit the reuptake of serotonin (5-HT) into the presynaptic neuron, increasing serotonin levels in the synaptic cleft, thereby enhancing serotonergic neurotransmission.
- SNRIs: Inhibit the reuptake of both serotonin and norepinephrine, leading to increased neurotransmitter activity and improved mood stabilization.
- Antiepileptics:
- Increase GABA availability (e.g., valproate).
- Bind to the alpha2-delta subunit of voltage-gated calcium channels (gabapentin, pregabalin), reducing neuronal excitability and exerting anxiolytic effects.
- Atypical Antipsychotics:
- Antagonize dopamine D2 and serotonin 5-HT2A receptors.
- Reduce dopaminergic and serotoninergic activity, helping stabilize mood and reduce anxiety symptoms.