Haloperidol primarily acts by blocking dopamine (D2) receptors. This dopamine blockade in the cerebral cortex improves cognition and reduces delirium. Along with the dopamine blockade, haloperidol has anti-inflammatory properties. It inhibits production of lipopolysaccharide induced pro-inflammatory cytokines, interleukin (IL-1) and tumor necrosis factor alpha (TNF-α). Haloperidol also increases levels of Interleukin -1 receptor antagonist (IL-1RA), an anti-inflammatory cytokine that blocks the action of other pro-inflammatory cytokines. If unchecked, the inflammatory cytokines cause impaired concentration, sleep disturbances, and agitation the cardinal symptoms of delirium; and induce a reduction in cholinergic activity. Given the inhibitory effect of acetylcholine on certain cytokines such as interleukin-6, a repetitive cycle of inadequate regulation of inflammation due to cholinergic depletion ensues. Haloperidol with its anti-inflammatory properties seeks to mitigate this repetitive vicious cycle.