Overview & Classification - The Chill Pill Intro
- Anxiety: Apprehension from anticipation of danger (source often unknown).
- Insomnia: Difficulty initiating/maintaining sleep, or non-restorative sleep.
Key Neurotransmitters & Roles:
| Neurotransmitter | Role in Anxiety/Sleep |
|---|---|
| GABA | Major inhibitory; ↓excitability, promotes calm/sleep |
| Serotonin (5-HT) | Regulates mood, sleep, anxiety; SSRI target |
| Norepinephrine (NE) | Mediates stress/arousal; ↑ in anxiety |
| Melatonin | Pineal hormone; regulates circadian rhythm, sleep onset |
- Anxiolytics: Benzodiazepines (BZDs), SSRIs, Buspirone.
- Hypnotics: Z-drugs, BZDs, Melatonin agonists.
⭐ GABA is the principal inhibitory neurotransmitter in the CNS, and its potentiation is a common mechanism for anxiolytics.
Benzodiazepines - GABA's Best Buds
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Mechanism: Allosteric modulators of GABA-A receptors; ↑ frequency of $Cl^-$ channel opening, enhancing GABAergic inhibition.
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Classification & Key Uses:
Duration Examples (📌 Mnemonic) Primary Uses Short Midazolam, Oxazepam (📌 M.O.) Procedural sedation, Insomnia Intermediate Lorazepam, Alprazolam (📌 L.A.) Anxiety, Insomnia, Status Epilepticus Long Diazepam, Clonazepam (📌 D.C.) Alcohol withdrawal, Seizures, Spasms (📌 M.O.: "Mostly Over"; L.A.: "Lasts Awhile"; D.C.: "Doesn't Cease") -
Other Clinical Uses: Panic disorder, Muscle relaxation, Pre-anesthetic sedation.
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Adverse Effects: Sedation, Ataxia, Anterograde amnesia (📌 "Forget me drug"), Dependence, Withdrawal syndrome (rebound anxiety, seizures), Respiratory depression (↑ risk with opioids).
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Contraindications: Myasthenia gravis, Sleep apnea, Acute narrow-angle glaucoma. ⚠️ Caution in elderly.
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Antidote: Flumazenil (competitive antagonist). Dose: 0.2 mg IV, repeat prn (max 1-3 mg).
⭐ > Flumazenil can precipitate seizures in BZD-dependent patients or those with tricyclic antidepressant (TCA) overdose.
- BZD Withdrawal Management:
Non-BZD Anxiolytics - Beyond Benzos
| Drug | MoA | Onset | Dependence | Key Uses | Common Side Effects |
|---|---|---|---|---|---|
| Buspirone | 5-HT1A partial agonist | Delayed (2-4 wks) | Low | GAD | Dizziness, nausea, headache |
| SSRIs/SNRIs | Serotonin/Norepinephrine reuptake inhibitor | Delayed (2-4 wks) | Low | Chronic anxiety (GAD, Panic, SAD), OCD, PTSD | GI upset, sexual dysfunction, insomnia |
| Beta-blockers (Propranolol) | Beta-adrenergic antagonist | Rapid (30-60 min) | Low | Performance anxiety, somatic symptoms (tremor, palpitations) | Bradycardia, hypotension, fatigue |
- SSRIs/SNRIs: First-line for most chronic anxiety disorders.
- Buspirone: Good for GAD, especially if BZD concerns; no immediate effect.
- Beta-blockers: Best for situational/performance anxiety with prominent physical symptoms. 📌 "Propranolol Performs under Pressure"
Non-BZD & Other Hypnotics - Sleepy Time Squad
📌 ZZZs for sleep (Zolpidem, Zaleplon, Zopiclone/Eszopiclone).
| Drug Class | MoA | Primary Use | Key AEs | Dependence Risk |
|---|---|---|---|---|
| Z-drugs (Zolpidem, Zaleplon, Eszopiclone) | Selective GABA-A $\alpha1$ modulator | Short-term insomnia | Complex sleep behaviors, amnesia, shorter duration vs BZDs | Low |
| Melatonin Agonists (Ramelteon, Tasimelteon) | MT1/MT2 receptor agonist | Sleep-onset insomnia | Dizziness, nausea; non-addictive | Very Low |
| Antihistamines (Diphenhydramine, Hydroxyzine) | H1 antagonism | Sedation, Insomnia | Anticholinergic effects, next-day drowsiness | Low |
⭐ Z-drugs are preferred over benzodiazepines for short-term insomnia due to their selectivity for the $\alpha1$ subunit of the GABA-A receptor, leading to fewer disruptions in sleep architecture.
High‑Yield Points - ⚡ Biggest Takeaways
- Benzodiazepines (BZDs) act via GABA-A receptors; Flumazenil is the antidote.
- Buspirone, a 5-HT1A partial agonist, has delayed onset and low abuse potential.
- Z-drugs (e.g., Zolpidem) selectively target alpha-1 GABA-A subunits for insomnia.
- SSRIs/SNRIs are first-line for chronic management of most anxiety disorders.
- Propranolol (beta-blocker) manages somatic symptoms of performance anxiety.
- Barbiturates have high abuse potential and cause enzyme induction; largely obsolete.
- Pregabalin is effective for Generalized Anxiety Disorder (GAD) by modulating calcium channels.
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