## Neurochemical Basis of Alcohol Withdrawal **Key Point:** Chronic alcohol use causes downregulation of GABA-A receptors (the brain's main inhibitory neurotransmitter) and upregulation of glutamate receptors (the main excitatory neurotransmitter). When alcohol is withdrawn, this imbalance leads to a hyperexcitable CNS state. ### Mechanism of Withdrawal 1. **Alcohol's acute effect:** Acts as a CNS depressant by enhancing GABA-A receptor function and inhibiting NMDA glutamate receptors. 2. **Chronic use adaptation:** The brain compensates by reducing GABA-A sensitivity and increasing glutamate receptor expression. 3. **Upon withdrawal:** Loss of alcohol's depressant effect combined with unopposed glutamatergic activity causes hyperexcitability. 4. **Clinical manifestation:** Tremor, autonomic hyperactivity, seizures, and delirium tremens. **High-Yield:** This GABA-glutamate imbalance is the cornerstone of alcohol withdrawal pathophysiology and explains why benzodiazepines (GABA-A agonists) are the first-line treatment. **Clinical Pearl:** The severity of withdrawal correlates with the degree of neuroadaptation, which depends on duration and quantity of alcohol use — not just the amount consumed on the day of cessation. ### Why Benzodiazepines Work Benzodiazepines enhance GABA-A receptor function, restoring the inhibitory-excitatory balance and preventing seizures and delirium tremens.
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