Antidepressant Drug Therapy
Most patients presenting for ECT are receiving tricyclic antidepressants,
monoamine oxidase inhibitors (MAOIs), serotonin reuptake inhibitors, lithium carbonate,
or a combination of these drugs. Tricyclic antidepressants block the reuptake of
norepinephrine, serotonin, and dopamine into presynaptic nerve terminals, thereby
increasing central sympathetic tone.[154]
Tricyclic
antidepressants have antihistaminic, anticholinergic, and sedative properties and
also slow cardiac conduction. These side effects are less common with the newer
types of antidepressant drugs such as trazodone, bupropion, and fluoxetine.[155]
The combination of centrally acting anticholinergics, such as atropine, with tricyclic
antidepressants can increase postprocedural delirium.[156]
MAOIs inhibit monoamine oxidase by irreversibly combining with
it to form a stable complex, thus blocking the metabolism of norepinephrine, serotonin,
and dopamine. The use of indirectly acting sympathomimetics in patients receiving
MAOIs can result in hypertensive crises.[154]
An
exaggerated response to direct-acting sympathomimetics may also be seen. Hypotension
in these patients should be treated with reduced doses of direct-acting sympathomimetic
agents. MAOIs can inhibit hepatic microsomal enzymes. They may interact with opioid
analgesics and cause excessive depression. Used concomitantly with meperidine, MAOIs
may result in severe, possibly fatal excitatory phenomena.[157]
Lithium carbonate prolongs the action of neuromuscular blocking
agents.[158]
Elevated lithium levels, higher than
the therapeutic range, can prolong the action of benzodiazepines and barbiturates.
Patients receiving lithium may demonstrate more cognitive side effects after ECT.
The American Psychiatric Association recommends discontinuation of lithium therapy
before ECT.[159]
