atracurium besylate
Tracrium

Available forms
Available by prescription only
Injection: 10 mg/ml

Indications and dosages
 Adjunct to general anesthesia, to facilitate endotracheal intubation, and to provide skeletal muscle relaxation during surgery or mechanical ventilation.  Dosage depends on anesthetic used, individual needs, and response. Doses are representative and must be adjusted.
Adults and children older than age 2: Initially, 0.4 to 0.5 mg/kg by I.V. bolus. Maintenance dose of 0.08 to 0.1 mg/kg within 20 to 45 minutes of initial dose should be administered during prolonged surgical procedures. Maintenance doses may be administered q 15 to 25 minutes in patients receiving balanced anesthesia.
Children ages 1 month to 2 years: Initially, 0.3 to 0.4 mg/kg by I.V. bolus when under halothane anesthesia. Frequent maintenance doses may be needed.

Pharmacodynamics
Skeletal muscle relaxant action: Atracurium produces skeletal muscle paralysis by causing a decreased response to acetylcholine (ACh) at the neuromuscular junction. Because of its high affinity to ACh receptor sites, atracurium competitively blocks access of ACh to the motor end-plate, thus blocking depolarization. At usual doses (0.45 mg/kg), atracurium produces minimal CV effects and doesn’t affect intraocular pressure, lower esophageal sphincter pressure, barrier pressure, heart rate or rhythm, mean arterial pressure, systemic vascular resistance, cardiac output, or central venous pressure. CV effects such as decreased peripheral vascular resistance, usually seen at doses greater than 0.5 mg/kg, are caused by histamine release.

Pharmacokinetics
Absorption: Administered I.V.
Distribution: Distributed into the extracellular space after I.V. administration; about 82% protein-bound.
Metabolism: In plasma, drug is rapidly metabolized by Hofmann elimination and by nonspecific enzymatic ester hydrolysis. The liver doesn’t appear to play a major role.
Excretion: Excreted in urine and feces by biliary elimination.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug. Use cautiously in elderly patients, debilitated patients, and patients with CV disease; severe electrolyte disorder; bronchogenic carcinoma; hepatic, renal, or pulmonary impairment; neuromuscular disease; and myasthenia gravis.

Interactions
Drug-drug. Aminoglycoside antibiotics, beta blockers, clindamycin, depolarizing neuromuscular blockers, enflurane, furosemide, isoflurane, lincomycin, lithium, nondepolarizing neuromuscular blockers, parenteral magnesium salts, polymyxin antibiotics, potassium-depleting drugs, procainamide, quinidine, quinine, thiazide diuretics: May enhance neuromuscular blockade related to atracurium. Carefully monitor patient.
Opioid analgesics: May cause additive respiratory depression. Use drug with extreme caution during and immediately after surgery.

Adverse reactions
CV: flushing,bradycardia, hypotension, tachycardia.
Respiratory: prolonged dose-related apnea, wheezing, increased bronchial secretions, dyspnea, bronchospasm, laryngospasm.
Skin: erythema, pruritus, urticaria, rash.
Other: anaphylaxis.

Effects on lab test results
None reported.

Overdose and treatment
Signs and symptoms of overdose include prolonged respiratory depression or apnea and CV collapse. A sudden release of histamine may also occur. A peripheral nerve stimulator is recommended to monitor response and to determine the nature and degree of neuromuscular block. Maintain an adequate airway and manual or mechanical ventilation until patient can maintain respiration unassisted.
 For treatment, administer cholinesterase inhibitors, such as edrophonium, neostigmine, or pyridostigmine, to reverse neuromuscular blockade; and atropine or glycopyrrolate to counteract muscarinic adverse effects of cholinesterase inhibitors. Monitor vital signs at least every 15 minutes until patient is stable, then every 30 minutes for next 2 hours. Observe airway until patient has fully recovered from drug effects. Note rate, depth, and pattern of respirations.

Special considerations
• Atracurium has a longer duration of action than succinylcholine and a shorter duration than tubocurarine or pancuronium.
• Prior administration of succinylcholine doesn’t prolong duration of action of atracurium, but it quickens onset and may deepen neuromuscular blockade.
• Maximum neuromuscular blockade increases with increasing dose. Repeated administration doesn’t appear to be cumulative nor is recovery time prolonged.
• Drug has little or no effect on heart rate and doesn’t counteract or reverse the bradycardia caused by anesthetics or vagal stimulation. Thus, bradycardia is seen more frequently with atracurium than with other neuromuscular blocking agents. Pretreatment with anticholinergics (atropine or glycopyrrolate) is advised.
 ALERT Use drug only if endotracheal intubation, administration of oxygen under positive pressure, artificial respiration, and assisted or controlled ventilation are immediately available.
• Deliver drug by I.V. injection because I.M. injection causes tissue irritation.
• Reduce dose and administration rate in patients for whom histamine release may be hazardous.
• Dilute to desired concentration, usually 0.2 to 0.5 mg/ml.
• Alkaline solutions such as barbiturates shouldn’t be mixed in the same syringe or given through the same needle with atracurium.
• Watch for bradycardia during drug administration; patient may need I.V. atropine.
• If indicated, assess patient’s need for pain medication or sedation. Drug doesn’t affect consciousness or relieve pain.
• Use a peripheral nerve stimulator to monitor responses during intensive care unit administration; it may be used to detect residual paralysis during recovery and to avoid atracurium overdose.
• Until head and neck muscles recover from blockade effects, patient may find speech difficult.
• Store in refrigerator at 2° to 8° C. Use within 14 days after removing from refrigerator, even if returned for storage.
• Drug is stable for 24 hours when diluted in most solutions except lactated Ringer’s (8 hours); spontaneous degradation occurs more rapidly.
Pregnant patients
• There are no adequate and controlled studies for use in this population.
Breast-feeding patients
• It’s unknown whether drug appears in breast milk; therefore, use cautiously in breast-feeding women.
Pediatric patients
• Safety and efficacy haven’t been established for children younger than age 1 month.
Geriatric patients
• Geriatric patients may be more sensitive to effects of drug.

Patient education
• Explain all events and procedures because patient can still hear.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use