Neostigmine blocking agent effects

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. 

Reversal of this type of neuromuscular block can be achieved with anticholinesterase drugs, such as neostigmine, which prevent the destruction by cholinesterase of acetylcholine released at nerve endings, allow the concentration to build up and so reduce the competitive effect of a blocking agent. 

C. Neostigmine is used primarily to reverse the effect of nondepolarizing neuromuscular blocking agents. 

If it is suspected that an antibiotic is contributing to prolonged neuromuscular blockade, the patient should be monitored and the effect of calcium (up to 1 g of calcium chloride slowly) should be observed. If this is unsuccessful, neostigmine (maximum dose 5 mg for an adult) or edrophonium (0.5 mg/kg) can be tried, but these agents may intensify a block due to cohstin, lincomycin, or polymyxin B. If the other remedies fail, 4-aminopjTidine (maximum dose 0.3 mg/kg) can be successful. Artificial ventilation should be continued until adequate spontaneous efforts are achieved and other possible factors, such as acidosis or electrolyte disturbances, are corrected. 

D. When neostigmine or pyridostigmine is used to reverse nondepolarizing neuromuscular blockade, glycopyrrolate is the preferred agent to block unwanted muscarinic effects (neuromuscular blockers, see p 472). 

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