Overview & History
Class: Non-depolarizing neuromuscular blocking agent (NDNMBA) – steroidal.
Introduced: 1972 (earlier than vecuronium and rocuronium).
Key distinction: Long-acting, vagolytic (causes tachycardia), and renally/hepatically cleared.
Use today: Decreasing in many centers due to cardiovascular side effects and long duration, but still relevant for specific cases (e.g., prolonged procedures without need for rapid reversal, some ICU settings historically).
Pharmacology
| Property | Pancuronium |
|---|---|
| Structure | Bisquaternary ammonium steroid |
| ED95 (adult) | ~0.05–0.06 mg/kg |
| Intubating dose | 0.08–0.12 mg/kg |
| Onset (intubating) | 2–3 minutes |
| Clinical duration | 60–100 minutes (long-acting) |
| Recovery index (25–75%) | ~20–30 minutes |
| Metabolism | 20–50% hepatic (deacetylation); 40% renal excretion |
| Active metabolite | 3-OH-pancuronium (weak activity) |
| Reversal | Neostigmine / sugammadex? No (sugammadex ineffective for steroidal NMBAs except rocuronium/vecuronium – but pancuronium is not reversed by sugammadex in clinical doses; neostigmine required) |
Note: Sugammadex has very low affinity for pancuronium. Do not rely on it for reversal – use acetylcholinesterase inhibitors.
Cardiovascular Effects (Critical differentiator from vecuronium)
Vagolysis (M2 receptor blockade) → tachycardia (dose-dependent, can be marked).
Sympathetic stimulation (norepinephrine release) → mild increase in BP, CO.
No histamine release (unlike tubocurarine).
Clinical implication: Avoid in patients with tachycardia, ischemic heart disease, or where HR increase is dangerous (e.g. aortic stenosis, uncontrolled thyrotoxicosis).
Compare with vecuronium: Vecuronium is hemodynamically neutral – no vagolysis, no tachycardia.
Clinical Use – When to Choose Pancuronium?
Advantages (fewer now):
Low cost (historical)
Reliable long duration for cases where you do not want patient to move for >1 hour without redosing
Good intubating conditions
Disadvantages:
Tachycardia often undesirable
Long duration problematic if case ends early or needs rapid reversal
Renal failure → prolonged effect (active metabolite accumulation)
Hepatic disease → prolonged effect
Reversal requires neostigmine (no sugammadex shortcut)
Current niche uses:
Prolonged abdominal/thoracic surgeries where stable long block needed
Rarely: status asthmaticus on ventilator (historically, but now rocuronium/vecuronium preferred)
In some resource-limited settings where cheaper than rocuronium
Dosing & Administration
Intubation dose: 0.08–0.12 mg/kg IV
Onset: 2–3 min (slower than rocuronium, similar to vecuronium)
Intubating conditions: good at 2–3 min, but not as fast as succinylcholine or high-dose rocuronium
Maintenance: 0.01–0.02 mg/kg q 30–60 min (or when T1 returns to 25% of control)
Infusion: Not typical (vecuronium/rocuronium preferred). If used: ~0.5–1.5 mcg/kg/min.
Renal impairment: Reduce dose and expect prolonged duration (up to 2–3 hours). Consider alternative (cisatracurium).
Hepatic impairment: Reduce dose; clearance reduced.
Reversal
Standard: Neostigmine 0.03–0.07 mg/kg + glycopyrrolate or atropine.
Timing: When T1 ≥10–25%, preferably ≥25%, and at least 3–4 twitches on TOF.
No sugammadex – unlike vecuronium/rocuronium. Important teaching point.
Adverse Effects & Precautions
| Effect | Notes |
|---|---|
| Tachycardia | Most common; dose-related; can be blunted by pretreatment with glycopyrrolate (paradoxically) but glycopyrrolate itself causes tachycardia; better to avoid pancuronium if tachycardia risky |
| Prolonged paralysis | Renal or hepatic failure; elderly |
| Residual block | High risk due to long duration – always confirm TOF ratio >0.9 |
| Anaphylaxis | Rare, but possible (steroidal structure) |
| Increased ICU weakness | Less relevant now, but long-acting NMBAs in ICU linked to critical illness myopathy |
Special Populations
Myasthenia gravis: Highly sensitive – dramatically reduced dose required.
Burns (>20% TBSA, 7–30 days post-burn): Resistance (upregulation of ACh receptors).
Upper motor neuron lesions/spinal cord injury: Resistance (denervation upregulation).
Electrolyte disturbance: Hypokalemia, hypermagnesemia → prolong effect.
Pregnancy: Crosses placenta poorly; minimal fetal effect. Category C.
Comparison Table: Pancuronium vs. Vecuronium (for trainees)
| Feature | Pancuronium | Vecuronium |
|---|---|---|
| Duration | Long (60–100 min) | Intermediate (30–60 min) |
| Cardiovascular | Tachycardia, ↑BP | Neutral |
| Renal clearance | 40% | 20–30% (metabolites inactive) |
| Hepatic clearance | 20–50% | 40–50% |
| Active metabolite | Yes (3-OH) | No (major metabolite inactive) |
| Sugammadex reversal | No | Yes (2–4 mg/kg) |
| Storage | Refrigeration not required | Reconstituted, stable 24h |
| Cost | Low | Moderate |
Clinical Pearls for Residents
Don’t pick pancuronium if HR >100 or CAD – vecuronium or rocuronium safer.
Renal failure? Avoid pancuronium – choose cisatracurium (Hofmann) or vecuronium (with caution).
Need fast reversal after long case? Pancuronium is not your friend – use rocuronium with sugammadex instead.
Accidentally gave pancuronium and case ends early? Prepare for prolonged recovery – monitor TOF, use neostigmine when appropriate post-tetanic count >1.
Never give pancuronium without anticholinergic for reversal – bradycardia from neostigmine may be unopposed, but pancuronium’s vagolysis usually protects – still, give glycopyrrolate/atropine per protocol.
Historical curiosity: Pancuronium was part of some lethal injection protocols (with midazolam and potassium). Not clinically relevant to anesthesia practice but important for ethics context.
Mnemonic for Board Review
“PAN” – Puts heart Accelerated, Non-depolarizing, Not for fast reversal
P: Prolonged duration, Pumps up HR
A: Acetylcholine – competitive antagonist (non-depolarizing)
N: No sugammadex (Needs neostigmine)
