Neuromuscular blocking agents respiratory

Interactions. Morphine (also pethidine and possibly other opioids) is potentiated by monoamine oxidase inhibitors. Any central nervous system depressant (including alcohol) will have additive effects. Patients recently exposed to neuromuscular blocking agents (unless this is adequately reversed, e.g. by neostigmine) are particularly at risk from the respiratory depressant effects of morphine. The effect of diuretic drugs may be reduced by release of antidiuretic hormone by morphine. Useful interactions include the potientating effect on pain relief of tricyclic antidepressants and of dexamfetamine. 

The anaesthetist ensures that the effects of neuromuscular blocking agents and opioid-induced respiratory depression have either worn off or have been adequately reversed by an antagonist the patient is not left alone until conscious, with protective reflexes restored, and a stable circulation. 

Hansen-Flaschen, J. H., Bray insky, S., Basile, C. and Lanken, P. N. Use of sedating drugs and neuromuscular blocking agents in patients requiring mechanical ventilation for respiratory failure. A national survey. JAMA, 266, 2870-2875 (1991). 

Quinine may potentiate the actions of neuromuscular-blocking agents causing respiratory depression. 

RESPIRATORY PARALYSIS Treatment of respiratory paralysis arising from an adverse reaction or overdose of a neuromuscular blocking agent includes positive-pressure artificial respiration with oxygen and maintenance of a patent airway until recovery of normal respiration is ensured. With the competitive blocking agents, this may be hastened by the administration of neostigmine methylsulfate (0.5-2 mg intravenously) or edrophonium (10 mg intravenously, repeated as required). 

Neuromuscular blocking agents are administered parenteraUy, generally intravenously. These drugs are hazardous and should be administered to patients only by cUnicians who have had extensive training in their use and in a setting where facilities for respiratory and cardiovascular resuscitation are immediately at hand. 

B. Neuromuscular blocking agents. Concomitant administration of magnesium with neuromuscular blocking agents may enhance and prolong their effect. Dose adjustment may be needed to avoid prolonged respiratory depression. 

Complications of surgeries, especially those on the abdomen or throat, necessitate skeletal muscle relaxation prior to surgery. Before the introduction of muscle relaxation, this was achieved by deep anaesthesia which itself is a hazard for patients (cardiac complications, respiratory suppression). Deep anaesthesia is no longer required by virtue of neuromuscular blocking agents providing adequate muscle relaxation for all surgical requirements. 

According to the experimental data, a plasma concentration of 4 pg/ml is needed for oximes to counteract the toxic effects of nerve agents such as neuromuscular block, bradycardia, hypotension and respiratory failure (13). This concentration has been assumed since then to be the minimum concentration of any oximes (regardless of identity or molecular weight) required to counter nerve agent intoxication in man (14). If pralidoxime is administered at a dose of 10 mg/kg, it produced a plasma concentration of > 4 pg/ml in 5-10 min and maintained a concentration of >4 pg/ml for a further 50-55 min in humans (15). For the oxime HI-6, it was found that plasma concentrations of > 4 pg/ml were reached in 4-6 min for 250 or 500 mg of HI-6 and were maintained for 125 min (250 mg dose) or 200 min (500 mg dose) (16). Obidoxime has the similar profile. It produced a plasma concentration of > 4 pg/ml from 5 min to 2-3 h after administration at the dose of 5 mg/kg (17). The pharmacokinetics of HLq-7 is similar to the oxime HI-6. The data presented by Eyer and his co-workers showed that the mean absorp-... 

The neuromuscular blocking effects of depolarizing and nondepolarizing agents are enhanced by aminoglycosides, and prolonged respiratory depression may occur. 

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