Interacting drugs - summary
 

+ Atracurium
 

Thiazide Diuretics

 The neuromuscular blocking effects of atrcurium  increased by thiazide       
   diuretics. Hypokalemia enhances the neuromuscular blockade,

General  Anesthetics eg. Enflurane/  Isoflurane/ alothane/Aminoglycosides/Lithium / Verapramil /Trimethaphan/Procaonamide/Quinidine 

These medications enhance the neuromuscular blocking action of atrcurium.
   
Magnesium Sulfate  

 When administered for the management of toxemia of pregnancy, enhance     
 neuromuscular blockade of pancuronium.

Other muscle relaxants 

 If administerd during the same procedure, consider the possibility of a synergistic or
  antagonist effect.

Phenytoin /Theophylline

 Phenytoin and theophylline cause resistence to, or reversal of, the
  neuromuscular blocking action of atracurium

Sucinylcholine

 Succinylcholine does not enhance duration but quickens onset and increase 
  depth of atracurium induced neuromuscular blockade

Acetylcholine esterase inhibitors eg. Neostigmine /Edrophonium, /Pyridostigmine

Antagonism is inhibited and neuromuscular block is reversed by  acetylcholineesterase inhibitors.
  

Corticosteroids  

 Prolonged weakness occur

Adjunct to general anesthesia.

Hypersensitivity- Allergic reactions(anaphylactic or anaphylactoid responses) rarely severe

Dermatologic- Rash, urticaria reactionat injection site

Musculoskeletal- Inadequate block, prolonged block

Cardiovascular- Hypotension, vasodilation(flushing) tachycardia, bradycardia,

Respiratory- Dyspnea, bronchospasm, laryngospasm

Hypersens.

Special precautions:

Neonates, severe CVS disorders, renal/hepatic dysfunction, myasthenia gravis and other neuromuscular disorders, severe electrolyte imbalance.

Concomittant therapy- Because potent inhalation agents or prior administration of succinylcholine enhance the intensity and duration of blockade of pancuronium, consider these factors when determing initial and incremental dosage.

Histamine release- excercise caution especially when substantial hisatamine release would be hazardous ( eg. patients clinically significant cardiovascular disease, severe anaphylactoid reactions or asthma)

Benzyl alcohol- this preoduct contains benzyl alcohol which has been associated with a fatal- gasping syndrome- in premature infants.

Bradycardia- during anesthesia may be most common with atracurium than other muscle relaxants because atrcurium has no clinically significant effects on heart rate. it will not counteract bradycardia or vaginal stimulation.

Usuage in neuromuscular diseases- in which potentaition of nondepolarizing agents has been noted .(eg myasthnia gravis, Eaton -Lmabert syndrome)

Malignnant hyperthermia- (MH) - halogenated anesthetic agents and succinyl choline are recongnized as prinicipal pharmocological agents i MH susceptible patients

Long-term use- when atrcurium is used in the ICU it is recommeneded that neuromuscular transmission be monitored continously during administrtion with the help of nerve stimulator.

Warnings

Anesthesia- atrcurium has no known effect on consciouness ,pain threshold or cerebration. Use only with anesthesia.

Elderly- nodifferences have been identified in effectiveness, safety or dosage requirements

Pregnancy- use during pregnancy onlyif potentail benefits outweigh the potentail hazards to the fetus.

Lactation- safey for usein the nursing mother is not established.

Children- safety and efficacy for children < 1 month old are not established

Indications:

Adjunct to general anesthesia.

Dosage:

Administer IV/ IM . Use may cause tissue irritation. Initial adult dose- 0.4 to 0.5mg/kg bolus injection.

Overdosage-

Symptoms -

Extended skeletal muscle weakness, decreased respiratory reserve, lower tidal volume, prolonged apnea, cardiovascular collapse and sudden release of histamine. sufficiently excessive doses of nondepolarizing muscle relaxants have no antidote.

Treatment

1. A peripheral nerve stimulator may be used to assesss the degree of residual neuromuscular blockade .

2. For residual neuromuscular blockade with respiratory paralysis or inadequate ventilation, maintain airway and administer manual or mechanical ventilation.

Missed dose

1. If you miss a dose of this medicine, take it as soon as possible.

2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosin schedule.

3. Do not double doses.

Pharmacology

Atrcurium a nondepolarizing skeletal muscle relaxant antagonizes the neurotransmitter action by binding competitively with cholinergic receptor sites on the motor end-plate.

Pharmacokinetics

The elimination half-lfe is about 20 minutes. Atrcurium is inactivated in plasma via two nonoxidative pathways .Some placenta transfer occurs.

Pregnancy

Use during pregnancy onlyif potentail benefits outweigh the potentail hazards to the fetus.

 Lactation

Safey for use in the nursing mother is not established.

Children- Safety and efficacy for children < 1 month old are not established