Lithium

Lithium remains the drug of choice for the treatment of bipolar affective disorder (manic-depressive illness). The lithium ion resembles sodium, potassium, magnesium, and calcium ions and may therefore affect the distribution and kinetics of all these electrolytes.^{[508] [509]} Lithium enters cells through sodium channels and tends to accumulate within cells.

Lithium, by activation of potassium channels, inhibits neuromuscular transmission presynaptically and muscular contraction postsynaptically.^[510] The combination of lithium and pipecuronium resulted in a synergistic inhibition of neuromuscular transmission, whereas the combination of lithium and succinylcholine resulted in an additive inhibition.^{[510] [511]} Prolongation of neuromuscular blockade was reported in patients receiving lithium carbonate and both depolarizing^{[512] [513]} and nondepolarizing neuromuscular blockers.^{[513] [514] [515] [516]} Only one report did not demonstrate prolongation of recovery from succinylcholine in patients receiving lithium.^[517] In patients undergoing surgery who are stabilized on lithium therapy, neuromuscular blockers should be administered in incremental and reduced doses and titrated to the degree of block required.