1. Clinical Overview
Atracurium besylate is a non-depolarizing, intermediate-duration, benzylisoquinolinium neuromuscular blocking agent (NMBA). It is a bisquaternary ammonium compound used as an adjunct to general anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. Its unique metabolism via Hofmann elimination and ester hydrolysis makes it independent of hepatic and renal function, making it suitable for patients with organ impairment. In the Indian context, it is a widely used, cost-effective alternative to other NMBAs.
| Onset | Duration | Bioavailability |
|---|---|---|
| 2-3 minutes after an intubating dose of 0.5 mg/kg | 20-35 minutes after an intubating dose | 100% (administered intravenously) |
2. Mechanism of Action
Atracurium is a competitive antagonist at the nicotinic acetylcholine receptors (nAChRs) of the postjunctional membrane at the neuromuscular junction. It binds to the alpha subunits of the receptor, preventing acetylcholine from binding and initiating depolarization of the muscle endplate. This results in flaccid paralysis of skeletal muscles.
3. Indications & Uses
- Adjunct to general anesthesia to facilitate endotracheal intubation.
- Provision of skeletal muscle relaxation during surgical procedures.
- Provision of skeletal muscle relaxation during mechanical ventilation in ICU settings.
4. Dosage & Administration
Adult Dosage: Intubation: 0.4-0.5 mg/kg IV bolus. Maintenance: 0.08-0.1 mg/kg IV bolus as required, typically every 20-35 minutes. Continuous Infusion: 0.3-0.6 mg/kg/hr (5-10 mcg/kg/min) after an initial bolus.
Administration: For IV use only. Must be administered by or under the supervision of an anesthesiologist or trained professional. Bolus doses should be given over 30-60 seconds to minimize histamine release. For infusion, dilute in a compatible IV solution (e.g., 0.9% NaCl, 5% Dextrose) to a concentration typically between 0.2-0.5 mg/mL. Use a controlled infusion device. Neuromuscular function must be monitored with a peripheral nerve stimulator.
5. Side Effects
Common side effects may include:
- Transient hypotension due to histamine release.
- Flushing, erythema, or skin reactions at the injection site.
- Tachycardia or bradycardia.
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Inhalational Anesthetics (Isoflurane, Sevoflurane, Desflurane) | Potentiate neuromuscular blockade, reducing atracurium requirement by 20-50%. | Major |
| Aminoglycosides (Gentamicin, Tobramycin) | Potentiate neuromuscular blockade. | Major |
| Magnesium Sulfate | Potentiates neuromuscular blockade. | Major |
| Calcium Channel Blockers (Verapamil, Diltiazem) | May enhance neuromuscular blockade. | Moderate |
| Lithium | May prolong neuromuscular blockade. | Moderate |
| Procainamide, Quinidine | May enhance neuromuscular blockade. | Moderate |
| Carbamazepine, Phenytoin | May induce resistance, requiring higher doses. | Moderate |
| Succinylcholine | Prior use may potentiate the depth and duration of atracurium blockade. | Moderate |
| Corticosteroids (chronic use) | May contribute to myopathy with prolonged blockade in ICU. | Moderate |
7. Patient Counselling
- Do inform your anesthesiologist about all allergies, especially to medications.
- Do disclose any history of muscle diseases (myasthenia gravis), asthma, or kidney/liver problems.
- Do not eat or drink as per pre-anesthesia fasting instructions.
8. Toxicology & Storage
Overdose: Prolonged and profound neuromuscular blockade leading to apnea, respiratory insufficiency, or paralysis. Cardiovascular effects (hypotension, tachycardia) from histamine release.
Storage: Store at 2°C to 8°C (refrigerate). Do not freeze. Protect from light. The product may be stored at temperatures not exceeding 30°C for up to 14 days. Once diluted in infusion solution, use within 24 hours. Do not use if solution is discolored or contains particulate matter.