Suxamethonium Procaine

Metoclopramide is structurally related to orthoclopramide, a procaine derivative, and it can prolong the action of suxamethonium because of competition for cholinesterase. However, its common side effects are similar to those seen with phenothiazine derivatives. In high doses, a range of extrapyramidal symptoms may develop. The anti-emetic effects of metoclopramide are due to two main actions. Centrally, it blocks dopamine in the CTZ and peripherally, it hastens gastric emptying, abolishes irregular intestinal contractions, and increases... 

Suxamethonium breakdown may be delayed by drugs that reduce plasma cholinesterase levels or compete as substrates. Many of the drugs that do this, such as procaine or propanidid, are... 

Procaine and cocaine are esters that are hydrolysed by plasma cholinesterase and may therefore competitively enhance the action of suxamethonium (succinylcholine)... 

Procaine and cocaine are esters that are hydrolysed by plasma cholinesterase and may therefore competitively enhance the action of suxamethonium (succinylcholine) (279). Chloroprocaine may have a similar action. Lidocaine also interacts, although the mechanism is not clear unless very high doses are used (280). 

Other measures, much disputed, include the prior injection of diazepam (58,59), procaine or hdocaine (57), vitamin C, suxamethonium itself (10 mg), and aspirin (51,52). The combined use of atracurium 0.05 mg/kg and hdocaine 1.5 mg/kg reduced the incidence of postoperative myalgia to 5% compared with 75% in controls (57). Thiopental, injected immediately beforehand, is also said to have some effect, as is giving the suxamethonium slowly. 

The neuromuscular blockade due to suxamethonium (succinyl-choline) can be increased and prolonged by lidocaine, procaine and possibly procainamide. These local anaesthetics all have some neuromuscular blocking activity and may theoretically also enhance the block produced by competitive neuromuscular blockers. Increased toxicity occurred when mivacurium and prilocaine were given together for regional anaesthesia. 

Uncertain. Some local anaesthetics (ester-type ) such as procaine appear to inhibit plasma cholinesterase, which might prolong the activity of suxamethonium. There may additionally be competition between suxamethonium and procaine for hydrolysis by plasma cholinesterase, which metabolises them both. These effects are particularly important in patients with abnormal plasma cholinesterase. Therapeutic procainamide plasma concentrations of 5 to 10 micrograms/mL have been found to inhibit cholinesterase activity by 19 to 32%. ... 

Information is limited but the interactions of suxamethonium with lidocaine, and suxamethonium with procaine appear to be established and of clinical importance. Be alert for signs of increased blockade and/or recura-risation with apnoea during the recovery period from suxamethonium. 

---