That covers everything from first principles through advanced clinical application. Here's a quick orientation to what was covered:

Midazolam works by potentiating GABA-A receptors (positive allosteric modulator at the benzodiazepine site). Its key clinical value is fast-onset anterograde amnesia with a short half-life (1.7-3.5 h). The most important danger is respiratory depression when combined with opioids. Reversed by flumazenil.

Ketamine works primarily as an NMDA receptor open-channel blocker, plus opioid and noradrenergic effects. It is the only anesthetic that both induces unconsciousness and provides powerful analgesia while largely preserving airway reflexes and respiration. It stimulates the heart in most patients. Its unique new role as a rapid antidepressant (IV 0.5 mg/kg) is mediated through AMPA receptors via its metabolite HNK, not NMDA blockade. Manage emergence delirium with a benzodiazepine. No specific reversal agent.

Fentanyl works as a pure mu-opioid receptor agonist (Gi-GPCR), inhibiting neuronal excitability. 100x morphine potency. Rapid BBB penetration due to high lipophilicity. Single boluses are short-acting (redistribution); infusions accumulate (context-sensitive half-time). The main dangers are dose-dependent respiratory depression, wooden chest syndrome with rapid large-dose injection, and synergistic depression with benzodiazepines. Reversed by naloxone (watch for re-narcotization).