Suxamethonium Diazepam

Nevertheless, some interactions of benzodiazepines with muscle relaxants used in anesthesia have been described. Diazepam has been reported to potentiate the effects of tubocurare (163) and gallamine (164) and to reduce the effects of suxamethonium (164). However, in 113 patients undergoing general anesthesia, intravenous diazepam 20 mg, lorazepam 5 mg, and lormetaze-pam 2 mg did not potentiate the neuromuscular blocking effects of vecuronium or atracurium (162). 

In 113 patients undergoing general anesthesia, intravenous midazolam 15 mg slowed recovery of the twitch height after vecuronium and atracurium compared with diazepam. The recovery index was not altered (162). However, in another study in 20 patients, midazolam 0.3 mg/kg did not affect the duration of blockade, recovery time, intensity of fasciculations, or adequacy of relaxation for tracheal intubation produced by suxamethonium 1 mg/kg, nor the duration of blockade and adequacy of relaxation for tracheal intubation produced by pancuronium 0.025 mg/kg in incremental doses until 99% depression of muscle-twitch tension was obtained (161). Furthermore, in 60 patients undergoing maintenance anesthesia randomly assigned to one of six regimens (etomidate, fentanyl, midazolam, propofol, thiopental plus nitrous oxide, or isoflurane plus nitrous oxide), midazolam did not alter rocuronium dosage requirements (165). 

Driessen JJ, Vree TB, van Egmond J, Booij LH, Crul JF. In vitro interaction of diazepam and oxazepam with pancuronium and suxamethonium. Br J Anaesth 1984 56(10) 1131-8. 

A 15-month-old infant developed seizures (132). Her heart rate was 200/minute, here peripheries were cya-nosed, and she had labored breathing, dilated pupils reacting sluggishly to light, and a temperature of 37.3° C. There was a rash over the right iliac fossa. Her neck and back were arched. Her liver was enlarged. There was no response to rectal diazepam, rectal paraldehyde, or intravenous lorazepam, but she responded to phenytoin and anesthesia with thiopental and suxamethonium. Amphetamine was detected in her urine. 

A 22-year-old man had a generalized tonic-clonic convulsion and loss of consciousness after an attempted superior laryngeal nerve block using 2% lidocaine 2 ml (282). The seizure was not terminated by intravenous diazepam 10 mg and he was intubated after intravenous thiopental and suxamethonium. He required two boluses of ephedrine 10 mg to maintain... 

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. 

Feneck RO, Cook JH. Failure of diazepam to prevent the suxamethonium-induced rise in intra-ocular pressure. Anaesthesia 1983 38(2) 120-7. 

A comparative study of 10 patients given gallamine and 4 others given gallamine with intravenous diazepam 150 to 200 micrograms/kg found that the diazepam prolonged the duration of activity of the blocker by a factor of three, and doubled the depression of the twitch response. Persistent muscle weakness and respiratory depression was seen in 2 other patients given tubocurarine after premedication with diazepam. A small reduction (approximately 10%) in neuromuscular blocker requirement has been described with diazepam and tubocurarine or suxamethonium (succinylcholine), but see also (b) below. ... 

The duration of paralysis due to suxamethonium was reduced in one study by 20% when diazepam (150 micrograms/kg) was also given and the recovery time was shortened. Diazepam also slightly reduced the time to 25% and 75% recovery of twitch height in patients given vecuronium by about 15% (not statistically significant). In animals, diazepam increased the mean dose of rocuronium required by 13%, but this was not statistically significant. ... 

In other studies diazepam was found to have no significant effect on the neuromuscular blockade due to alcuronium, atracurium, gaiiamine, pancuronium, suxamethonium " or tubocurarine. " " Lo-razepam and lormetazepam have been reported to have little or no effects on atracurium or vecuronium, and midazolam has been reported to have no eftect on suxamethonium or pancuronium. ... 

---