Pharmacology · 10 min
Pharmacology — last-night quick guide
Induction + paralytics + reversal + opioids + locals + emergency.
Rule
Induction defaults
Stable: propofol 1.5–2.5 mg/kg. Cardiac/septic: etomidate 0.2–0.3 mg/kg. Asthmatic/RSI/shock: ketamine 1–2 mg/kg. Trauma + bleeding: ketamine + roc + early blood.
Paralytics
| Drug | Dose | Onset | Duration |
|---|---|---|---|
| Succinylcholine | 1.0–1.5 mg/kg IV | 30–60 s | 5–10 min |
| Rocuronium | 0.6–1.2 mg/kg IV | 60–90 s | 30–60 min |
| Vecuronium | 0.08–0.1 mg/kg | 3 min | 30–45 min |
| Cisatracurium | 0.15–0.2 mg/kg | 3–5 min | 40–75 min (Hofmann) |
Rule
Reversal
Sugammadex 2 mg/kg if TOF ≥ 2 twitches; 4 mg/kg if PTC 1-2 only; 16 mg/kg for emergent reversal of just-given roc/vec. Neostigmine 0.05 mg/kg + glyco 0.01 mg/kg only when TOF ≥ 2 — never for deep block.
Watch out
Succinylcholine contraindications
Burns/crush >24 h. Denervation/upper motor neuron lesion >24 h. Muscular dystrophy. Hyperkalemia known. MH susceptibility. K+ >5.5.
Opioids
| Drug | Dose | Onset | Tip |
|---|---|---|---|
| Fentanyl | 1–2 mcg/kg | 2–3 min | Bolus for laryngoscopy attenuation |
| Remifentanil | 0.05–0.5 mcg/kg/min | 1 min | OIH if high-dose long case |
| Hydromorphone | 0.01–0.02 mg/kg | 5–10 min | PO equivalent: 4 mg PO ≈ 1.5 mg IV |
| Morphine | 0.05–0.1 mg/kg | 10–20 min | Histamine release; avoid in renal failure |
Rule
LAST recognition + treatment
Sx: tinnitus → metallic taste → muscle twitching → seizures → arrhythmia → cardiac arrest. Tx: airway + 100% O2 + 20% Intralipid 1.5 mL/kg bolus then 0.25 mL/kg/min × 10 min. AVOID lidocaine, vasopressin. Use small-dose epi (≤1 mcg/kg). Cardiac arrest = continue lipid + ACLS modified.
Mnemonic — Na-channel blockers
QRS widening on tox screen
Wide-QRS tox = Na-channel block
- TricyclicsTCAs (amitriptyline, nortriptyline) — Na-channel blockade; treat with bicarb 1-2 mEq/kg
- Class 1A/1CQuinidine, procainamide, flecainide — Na-channel blockade
- CocaineLocal anesthetic Na-channel blockade + sympathomimetic; benzos + bicarb, avoid β-blockers alone
- DiphenhydramineTCA-like Na-channel blockade at high doses
- HyperkalemiaNot a drug but causes the same wide-QRS picture; calcium first
Sodium bicarbonate 1-2 mEq/kg is the unifying treatment for Na-channel toxicity — overdrives the block + alkalinizes serum.