Several factors influence the action of neuromuscular blockers, these include:
1. Blood flow to muscles
If blood flow is rapid, onset of action is rapid and duration of action is short.
Acidosis potentiates the effects of non-depolarizing neuromuscular blockers.
4. Potassium concentration
6. Atypical Pseudo cholinesterase
Suxamethonium is metabolized by pseudo cholinesterase. If there is deficiency or presence of atypical pseudo cholinesterase, it might lead to respiratory paralysis or apnea.
7. Anti-arrhythmic drugs
Drugs like quinidine have curare like actions causing relaxation of muscles. They potentiate the effects of non-depolarizing neuromuscular blockers.
8. Myasthenia gravis
In myasthenia gravis, peripherally acting neuromuscular blockers are not administered.
9. Renal/ liver diseases
Care must be taken as Rapacuronium and Vecuronium are metabolized by the liver.
d-Tubocurarine and Metocurium are eliminated through the kidneys.
10. Calcium channel blockers
Thiazide diuretics produce hypokalemia, which potentiates the effects of non-depolarizing neuromuscular blockers.