Anticonvulsants and anxiolytics: Barbiturates

Barbiturates are a class of medications that are used as anticonvulsants to manage seizure disorders; to induce anesthesia in surgical procedures; as anxiolytics to relieve anxiety; and to manage insomnia.

Barbiturates enhance the effect of gamma-aminobutyric acid, or GABA, which is the major inhibitory neurotransmitter in the brain, by binding to its receptor.

It’s pretty well-established that your brain’s really important.

It controls your feelings, your movements, your sleep, your memory… It controls everything, whether you’re aware of it or not.

The cells that make up our brain are called neurons.

Neurons communicate with each other through neurotransmitters.

When one neuron is stimulated, it’ll release excitatory neurotransmitters like glutamate, which bind to receptors on the next neuron.

This causes the next neuron to depolarize and release its own excitatory neurotransmitters, propagating the signal throughout the brain.

Now, we also have inhibitory neurons that will shut down this chain of events.

These neurons release the main inhibitory neurotransmitter in the nervous system, gamma-aminobutyric acid, or GABA, which binds to GABA receptors on other neurons.

These receptors are large multi-unit complexes that form ligand-gated ion channels, which open up to let Cl- ions into the cell.

The influx of negatively charged ions causes hyperpolarization, where the cell’s membrane potential becomes more negative, which means it’s much more difficult for it to depolarize and fire off an action potential, and that means it’s less responsive to stimuli.

Now, there are cases where neurons in the brain start sending out more excitatory signals than normal.

This can occur due to either too much excitation by the excitatory neurotransmitters, or too little inhibition by the inhibitory neurotransmitters like GABA.

Excessive excitatory signals can cause psychiatric disorders like anxiety, and neurological disorders like seizures and epilepsy.

Okay, so one way we can decrease the excitatory signals is by enhancing the effect of inhibitory neurons through medication like barbiturates.

Common medications in this class include amobarbital, butabarbital, methohexital, PENTobarbital, PHENobarbital, and primidone, which is a prodrug of PHENobarbital.